Yes, absolutely - the house is a pretty big country side house from 1925, not uncommon in Germany. But (almost) impossible to insulate efficiently. My estimates where €150k to €200k, just for the insulation, windows, and renewed heaters. In comparison, an 'oversized' 70 kWp PV only costs €100k, and also returns some income when not all of the power is used.

The parameters widely differ between country and city: In the country, you usually have space (but lack money), in the city, you lack space but can often work with a pretty good income (= build a new, energy optimized house).

Every house is different. If I build a new house today, of course this would look different.

I live in a house in a village in the Netherlands. The house is from 20-150 years old, depending on which section you're in.

It is cold as f in this place all winter. It's also hot as f in these new 37 degree summers.

So the question is, is the problem the old homes, or our insistence to live in inefficient buildings in places with poor climates?

Of course in this country, there's more demand for housing than can be met, so living someplace modern (efficient/comfortable) is not necessarily an option based on price. So the next choice is relocating to a different country which has a more livable climate.

I love architectural history, but we would all be better off if modern engineering and design decisions were made on new structures to replace the grossly inefficient current ones.

Currently living in a rich area, 20 stories very modern high apartment complex. The first thing I thought when stepping into the apartment for the first time with its massive windows was “jikes the windows are leaking heat like crazy”. In my old home that was 60 years old it had way better insulation (with triple layered windows).

What I’m trying to say is that this is about incentives, not about how old things are. The modern building let their tenants cover the AC cost while the old one had water heating instead included.

Not sure what part of the world you're in, but OP was describing Germany, and I'm in Netherlands. Both of these countries have pretty strict requirements for energy efficiency of new buildings. So at least here, it would be safe to assume that a < 10 year old home or apartment would be much more efficient (and comfortable) than a 30+ year old one.

Also, there's a new government initiative to provide incentives and special financing for property owners (who rent their property) to bring the efficiency of all properties up to a decent minimum level by 2030 if they wish to be allowed to continue renting them out. I imagine there may be some exclusions for certain very old properties, especially historical/monumental ones. But regardless, it should have a big positive impact.

Indeed. for example UK has the most expensive and some of the worst buildings in EU, I have seen soviet buit homes that are better than some newbuilds over here. The word of the market is 'never buy a newbuild' because you never know what they fucked up.

The stories sound like comedy: entire block of flats was built the wrong way round, someone moved into theyr flat and found the balcony was missing - the balcony door just led to a 30 meter drop. They forgot to lay cable down for internet, so a new block only has 8 megabit ADSL. The building I am in, they made the holes for fire sprinkles in the wrong place - so there is a hole in the ceiling, but nothing behind it. The sprinkler is 20 cm away from it, inside the ceiling, and if something goes wrong it won't actually be able to pop out

From what I've seen with old country side houses in France just insulating the roof and the windows can already bring very good results (heat lost through walls is usually only around 25% of all the losses). A quick and cheap solution for the roof is to lose the attic and blow the isolating material directly on it.

yeah, there are so many old houses are still sitting around in Europe. My area almost every house was built in the late 1800s. Looks pretty nice, but insulation sucks.

That estimate seems insane. Was that a “we’re too busy, go away” estimate?

How big is the house?

It is quite a standard 2-generations house (at that 1925 time), 250 m² and two apartments, + a base level with an office. I am not saying that this is the universal standard - but it is _a_ standard that I do see quite often here, especially if you look outside cities, where the turnaround for reconstructon of houses is slower.

.. and this was quite thoroughly calculated. I can tear down the house and build a new one, but apart from the waste of resources - building a new one will also cost minimum €200k - so I thought, why not 'oversize' PV, if it only costs €100k and can heat the house without improving on insulation?

To emphasize, this conclusion will likely not apply to the majority of people (especially here on HN) because as many have said here, parameters and contexts differ widely.

Does the calculation stay the same looking decades ahead?

I'd have guessed that 200k to rip it down & build a new house that has great insulation - or even to just retrofit insulation and other upgrades to the existing building - would be expected to last longer before costing the same amount against to replace (and/or pricey maintenance/insurance of the more expensive PV, aircon etc.). And might therefore work out cheaper when looked at as a 50 year question rather than 1 year one?

I don't presume to know more than you, not only don't I know about your specific situation I also know very little about these subjects generally, I'm just curious.

Yes, it is difficult and I don't think it is possible to come up with a solution that fits all. What limited I can say: Insurance for the PV is cheaper than insurance for the insulation. That is because more problems with insulation can appear (e.g. fire damage, moisture) than with PV. Insulation of old houses is also far more complex than PV (someone pointed that our here).

.. it was mentioned somewhere here, too: For some, the best solution will be to focus on reducing energy consumption; for other, the better option will be to focus on increasing local energy production. And a combination of both might be best for most.

Wow that sounds too high. Maybe insulate only the parts you frequently use, perhaps?

No offense - but insulation doesn't really work like this. If you insulate only one part, you will get massive problems with moisture through heat transfer. With insulation of old houses, so much can go wrong and then the only solution _is_ tearing down the house and building a new one.

This is very interesting. I was told by some energy expert I could isolate 3 out of 4 outer walls and it would work fine. Do you have some documentation on the “moisture through heat transfer” issue?

I do not have one at hand, but you should find this in almost any guide. It is not complicated: If you insulate 3 walls and leave one wall untouched - this wall will always be the coldest. That means the water contained in your air will condensate always at this wall (because it is the local minimum), resulting in mould and mildew on this wall over time.

Now, there are all kinds of solutions and they all have caveats. As someone said here, old houses are build so that walls are semi-permeble, meaning that heat constantly wanders to the outside. That also means that the dew point is pretty far towards the outside in winter - water can get out of the house. If you insulate the inner wall, the dew point will move more towards the inside, meaning your walls will get wet and water will take longer to move outside. If you insulate the outside, water cannot get out at all - you must find another solution to get the moisture out of the house. It gets more complicated the more you dive into this topic.

But your logic seems to indicate that only one wall will have condensation instead of 4. It’s still an improvement no?

You're concentrating 4 wall's worth of condensation onto just one wall. Instead of being spread out, all the moisture gets on the one wall.

No, that is not how condensation works, otherwise you would have automatically more condensation on the wall in a larger room. The amount of condensation on the walls is not dependent on the size of the room or the fact that it condensates on the other walls. It depends on air humidity, air temperature, wall temperature and finally, very important, wall humidity. Water will not keep on accumulating on the wall, it will reach an equilibrium at some point, when the wall itself has become moist. The fact there is condensation or not on the other walls has negligible impact on total air humidity, most of all in larger rooms. And that's the only factor out of the 4 I could imagine being impacted by condensation (or not) on the other walls.

Hence, I still do not understand the logic why isolating only a subset of walls instead of all of them would be a problem.

As I said, I had an energy efficiency specialist at my home which said that isolating 3 walls would be 75% as efficient as isolating 4 and totally recommended. So far, I have not seen any solid logic supporting the fact that isolating only 3 walls instead of 4 would *increase* the risk of mold compared to either, 4-walls all insulated, or, zero walls insulated.

The point is it won't reach an equilibrium. The outside of the house changes temperature with the day night cycle. The one uninsulated wall will be closer to the outside temperature than the other walls.

As the house cools at the end of the day the uninsulated wall will be colder than the other walls and if it's below the dew point condensation will form on it. If the temperature differential is high enough in comparison to difference in insulation between the walls then enough water will leave the air to keep the dew point below the temperature of the insulated walls and so that one wall will collect the majority of moisture (at 30C a meter cubed of saturated air carries about 30mls of water so yes condensation on a surface can heavily impact humidity). Once a wall becomes moist it will still acumulate water if it's below the dew point.

You likely will have seen real life examples of this when you look at single pane windows in otherwise insulated houses and seen them fog up/ have condensate form on them while the walls around them remain dry (if you haven't seen this but have been to houses with single pane glass in your area then condensation won't be an issue where you live).

As to your 75% efficiency point it will in fact have a lower efficiency as heat transfer increases with temperature differential. Since the room has a higher temperature differential with the outside the less insulated wall will be faster at transfering heat.

That is not to say that insulating 3 walls is a bad idea, it will almost certainly improve a rooms U value, but the worse the insulation on the remaining original wall, ceiling, and floor the less difference the 3 walls will make to the rooms U value and thus how quickly the room transfers heat.

> Do you have some documentation on the “moisture through heat transfer” issue?

Warm/er air can hold more moisture than cold/cooler air. If part of the house is warm, and you happen to cook and/or shower in it, it will have a high moisture content.

But water vapour diffuses through-out an enclosure. So that water in a gaseous phase will equally spread everywhere (eventually).

When it reaches the uninsulated part/s of the structure, the air is colder and so can't hold as much moisture leading to condensation. Get lots of condensation, and you have an environment that is suitable for mold growth (which can then release spores in the air and mess up indoor air quality (IQA)). Not to mention that water is a universal solvent, and so will turn your structure (stone, masonry, concrete, wood) to mush over time.

The place of condensation will most likely be a surface that is a large temperature change: so in the winter your inside is warm, and your uninsulated outside walls are cold.

Adding to this -- climates that have cold winters and a tradition for building well-insulated homes have detailed construction customs for how to deal with this.

Today, it's generally solved by having an airtight sheet (plastic) between the insulation and the inner wall. Sometimes placed inside the insulation. This ensures a temperature gradient that will not cause condensation inside the house.

You'll generally put a sheet that's porous but not airtight outside the insulation, to reduce heat loss due to convection and also provide an extra layer of defense against moisture damage due to wind-blown rain.

This technique necessitates good ventilation (often powered) if it's used throughout the entire house. This is to avoid saturating the inside air with humidity due to breathing and other activity, itself leading to the condensation you're trying to avoid. It can sometimes be just on e.g. floors and ceilings. Then, the rest of the structure might still be leaky enough that mostly passive ventilation will do the trick.

Older houses handle the problem by just being so leaky that condensation won't be a problem.

I still don’t get why there would be *more* moisture on the uninsulated inner wall compared to before insulating 3 out of 4 walls.

Because you add the same amount of moisture (showers, cooking, breathing), and it needs to get out before it's was evenly over all 4 walls, now only one. Your total indoor humidity is going to go up because there is less taking care of it.

That said, insulation is still the right answer, but it ain't cheap. OP should probably tear down that beautiful old house for something more modern.

Most people know that hot air rises. It's helpful to think of airflow in terms of energy (temperature is a measure of the average kinetic energy of air molecules).

Hotter air has more energy and thus will naturally "flow" towards cooler areas with less energy until equilibrium is reached.

In this example, the higher temperature air holds more moisture. That moisture will be carried along and dispersed towards the cooler wall, where it could condensate.

I do see your point, you believe the air near the uninsulated wall will have even more moisture because it’s now the only cold wall out of 4 walls. So all the moisture goes there instead of being split in 4.

But a wall will stop condensating water when reaching a certain degree of humidity. So I’m not entirely convinced one can simply divide the amount of humidity in the air by the amount of uninsulated walls (or sqm).

> I do see your point, you believe the air near the uninsulated wall will have even more moisture because it’s now the only cold wall out of 4 walls. So all the moisture goes there instead of being split in 4.

The air will not have more moisture, but rather all the moisture problems will be towards/on the uninsulated wall.

> But a wall will stop condensating water when reaching a certain degree of humidity. So I’m not entirely convinced one can simply divide the amount of humidity in the air by the amount of uninsulated walls (or sqm).

Condensation will never stop on a cold wall until all the moisture in the air is removed. If you boil a pot of water the air will fill with moisture, and the entire house will have a high humidity. But because one particular wall is cold because of a lack of insulation the condensation (water going from vapour to liquid phase) will be concentrated on that particular wall.

The condensation will continue to occur as long as you continue to add moisture to the air via cooking and bathing (hot showers, baths).

Say you have a room completely insulated except for 1 sqm. Will the entire moisture condensate on 1sqm? That could represent 1cm of water on the wall, that's physically impossible. There's a maximum amount of moisture that can condensate per unit of surface, it cannot be infinite. Where does the water go after condensating? Even if you consider it drips down and stays on the floor, the amount of water on the wall at any given time still has a maximum.

That's the bit I am missing here, it just does not add up, condensation is not something that simply keeps accumulating water on a wall if it's cold enough, there's a saturation at some point. The question is, how fast is this saturation reached? If it's fast, then isolating one out of 3 walls may not create additional moisture on the non-insulated wall.

Sorry, I hope I don't come over as being stubborn, I'm genuinely interested in insulating (I have to do it at some point), I just like to understand things and so far I do not understand why isolating 3 walls out of 4 would generate additional moisture on the remaining wall.

'That could represent 1cm of water on the wall, that's physically impossible. There's a maximum amount of moisture that can condensate per unit of surface, it cannot be infinite. '

' I do not understand why isolating 3 walls out of 4 would generate additional moisture on the remaining wall.'

you gey problems with mold way before you are anywhere near 'the physical limir of condensarion'. You dont want to be near it.

The question is not whether the amount of consensation will double or quadruple. It is weather you will have mould problems. If your wal starts getting wet, you will have mould peoblems.

Several floors were mentioned. Perhaps insulating one of them completely is an option then?

As far as I know, around 1,000 Euro / sqm is a good estimate for bringing a 200+ kWh/(sqm * a) house down to about 85-100 kWh(sqm * a)

> better insulation

better insulation is not cheap and therefore not everyone can afford to do it. Also the same people who want renewables are usually opposed to building new housing so there's that.

The actual insulation is stupid cheap when you look at the ROI. However, installing in on an existing house is really tricky and you can cause a lot of moisture related damage if you do it in the wrong way.

The house I live in, like everyone's in my street, is from the late 1800s. Insulating those houses from the outside is very expensive, to the tune of 200k, where the house is worth around 500k in the inflated environment we're in. At the very same time, I haven't found a single insurance company willing to insure the house after insulation for insulation related moisture damage.

This makes insulating this house an absurdly bad financial decision, since once you have moisture damage in any part of this material, you can basically demolish most of the walls since it soaks like a sponge.

Mind you, I have not started going into the pitfalls of the legality of even touching a house this old in Germany, where you have to deal with "Denkmalschutz".

Insulating new construction and retrofitting insulation are two absolutely different things and barely have anything to do with each other from the cost-benefit ratio.

Absolutely, and the thing about old houses is that they've evolved to keep moisture and ventilation in check without access to modern tech. Modern tech, as you point out, usually makes things worse.

My house in Sweden is from the 1950's and I still had to be _very_ mindful when adding insulation. The best thing I've found is cellulose-based insulation, basically shredded newspapers lined with salts and pressed to sheets. The can buffer a lot of moisture without developing mold.

Same here in Spain. But in this climate I don't need insulation anyway.. My energy costs are 60 euro a month in winter and 30 in summer. No point even trying to insulate.

Including heating/gas?

Yes included. I don't have gas heating anyway. Just a little plug-in electric radiator.

Is that not energy

Have you looked at hempcrete? I'm in France and have just started looking at better insulation for an old stone large property.

Interesting, why isn't the moisture on walls behind insulation ever an issue on new construction?

In addition to what was already said, there definitely is and has been many moisture issues on walls and exteriors in new construction. A condo building near me had to have its exterior completely torn off, and lots of sheathing, insulation, cladding, etc replaced due to a botched install of EIFS. Google for “EIFS failures.” This was a big problem in the 80s/90s or so but apparently it’s still happening, at least with subpar builders.

Because they use a dual layer construction with an air gap between the inner an outer walls. This gives space for condensation to occur and evaporate again without effecting the living space.

In old buildings with solid walls you can get condensation on the walls that will evaporate because the living space is heated and we'll ventilated. If you clad that wall in insulation you can prevent the evaporation which leads to damp problems.

> Interesting, why isn't the moisture on walls behind insulation ever an issue on new construction?

Newer building codes have started to mandate more external insulation:

* https://www.buildingscience.com/documents/insights/bsi-001-t...

Depending on the climate zone, up to half the insulation may be mandated to be on the outside (behind some kind of cladding (brick, stucco, siding) to protect it from UV and bulk water).

Per the above article, by having the outside be insulation, your interior structure is kept warmer, and so condensation is less likely to occur.

Do a search for "Joseph Lstiburek" and "Matt Risinger", who have lots of articles and videos on building science.

* https://en.wikipedia.org/wiki/Building_science

Old constructions are diffusion open, meaning moisture can move freely in and out of it. New constructions are diffusion closed, meaning you have a steam barrier on the inside which blocks the moist indoors air from traveling into the walls. This however requires an airtight house and mechanical ventilation.

In the U.K. the people who want renewables tend to be under 40s that can’t afford to buy a house. Those that actively don’t want renewables tend to own their own home and may have a couple the let out.

Pretty much no-one actively doesn't want renewables. They might not want them built very near them, but that's different.

There's a very obvious paper trail of people not wanting renewables.

As the article notes this price decline was predictable decades ago, but you can't really blame people for being dubious about predictions. Maybe the people who got it right were just lucky.

But since real actual installed wind and solar became cheaper a while ago, the people still openly arguing against renewables slide ever close to cartoon supervillain status.

People thinking renewables wouldn't be cheaper aren't people who don't want renewables. Why would they even get a mention?.

I'm not convinced enough people know that renewables are cheaper to make the latter claim you're making. For example, in some places as soon as renewables come online they get priority access to demand, and other fuel sources get the leftovers. That's still a subsidy, just by another name. So I don't know if they are cheaper.

Finally, the point about renewables isn't only cost, it's also reliability. The subsidy I just mentioned falsely obviates the need for renewables to be reliable from a cost perspective, but that doesn't mean that needing a high base load (and higher the more we move to electric vehicles) isn't the most important thing to supply.

And none of that is about people "not wanting renewables".

'That's still a subsidy, just by another name. So I don't know if they are cheaper.'

yeah, but fossil fuels get subsidies of all sorts, not just polluting for free, but even things like leaving the british taxpayer to pickup the bill for cleaning up old infrastructure they no longer need

https://www.theguardian.com/business/2019/jan/25/british-tax...

"Nuclear would have won if it weren't for you meddling kids!"

Let's not forget the close ties between German politicians and Gazprom executives, among other issues..

Yes, I'm sure the near universal failure of nuclear to compete around the world is due to a conspiracy in Germany.

I blame the Green movement. Those people really just wanted to destroy the planet. Not limit global change...

I see. The Green movement is globally all powerful, and you explain away the fact that the world is still not a Green utopia by saying the Green movement isn't actually Green. This is awesome mental gymnastics!

The alternate explanation is that nuclear is a sick technology, and the Green movement is not responsible for its failure. Nuclear was so weak even a group as feckless as the Greens could have success against it.

Greenpeace etc have long protested against nuclear, and have boogeymanned their way into the public consciousness on this topic. It's conceivably set us back decades and released millions of extra tons of CO2 in the process.

A classic correlation/causation confusion. Yes, Greenpeace complained about fission. No, that doesn't mean they caused fission's failure.

If there's many billions of dollars in value to be created, that will trump anything a NGO can whine about. That's why we're still burning so much fossil fuel. Nuclear was vulnerable because it wasn't creating value.

They have done sone damage, but you cannot lay the entire problem at their feet.

Do you think lobby from fossil fuel companies just sat on their hands all this time?

I'm not against them, but I think they should not be specially subsidised. Just pay what ever the market rate at the moment is. If it is not enough to cover investment too bad.

Surely they should be at least as equally subsidized as other energy sources, with the cost of external cleanup perhaps also factored in?

That would be fine with me, if every energy source had to pay its own negative externalities.

Will absolutely all of the externalities of mining, manufacturing and transport then be also applied to renewables?

Also, maybe if there is any risk of damage to surroundings like with hydro batteries there would be need to deposit amount of money that covers them fully.

Yes, they should. Otherwise we'll just drown in a hot sea of shit, only 50 years down the line. Everything needs to be sustainable, kind of by definition.

But as with any problem, let's first start with the stuff causing the damage.

Let's get oil and gas and coal to pay for EVERY negative externality.

You wrote: <<Just pay what ever the market rate at the moment is.>>

This is positive ridiculous. Are you serious in 2022? Your electricity is surely mostly sourced from hydrocarbons. Are you paying "true cost"? Surely not. If electricity was suddenly twice the cost due to carbon costs (which is probably the true environmental cost), you would be shouting from your windows to build more solar panels and wind turbines.

> Also the same people who want renewables are usually opposed to building new housing so there's that.

What? Why would you think that?

New housing lowers property demand.

Plus, people usually oppose nuclear which is an expensive but stable renewable option.

Lefties want new houses ? Thats a strange claim to make. The most left wing states in the US are the ones that build the least new buildings.

Rich corporate liberals are into trans rights, keeping abortion, etc. but they arent keen on new housing either. It puts a dent in their property portfolios.

Some people call these people "the left", I suppose, in which case yea they're not much keener on new housing than the rich corporate conservatives.

Theres also an element by which it is driven by high prices and loss aversion. A new homeowner with a $300k house and a 95% mortgage is gonna locally fight anything that drives up supply and drives them into negative equity even if their sympathies do trend left. Nobody fights new development as hard when prices are lower, which is probably partly why NY's strictest rent control (which drives down prices) coincided with the fastest building in the 60s.

They want new housing but often built by the government instead of evil property developers.

And new housing, .. but not built in their neighborhoods. Oh, and don't build over farmland or undeveloped green spaces.

Without being snarky, the problem here is that there is a tension between what people believe in general, and what they believe about their situations specifically, especially when they have an incentive to feel the opposite way about it. For example, people may know (or believe) that building duplexes and apartments in their neighborhoods will reduce their property values, or "ruin the character of the neighborhood" and so oppose them.

Private property developers simply dont want to build affordable housing. The margins are just lower than they are for luxury housing. Who would choose to make 4% profit when you could make 20?

They do lobby hard to remove building regulations in the name of building more affordable housing but they never actually build it unless local government actively forces them to with some of those regulations they hate, at which point they build the bare minimum and install a poor door.

They're always going to build the highest margin product for which there is demand. You're not going to get cheap housing until there is abundance. It's simple supply and demand.

It's not super expensive, really. And this is something that building codes can address - either via the gentle option of requiring all newly built dwellings to be thermally efficient, or the somewhat more assertive route of requiring any home sold to have adequate insulation.

> With all due respect, looking at your numbers my hunch is that you need better insulation.

With all due respect these are the kinds of "tiny" details that renewable enthusiasts conveniently forget. Yes, this person's house needs better insulation. As does everybody else's.

You can't just wave this away with "your math is wrong". These numbers reflect reality, not wishful thinking.

I wish you would expand and clarify the point you are trying to make. Currently it sounds like you are angry at a group of enthusiasts.

I think for me and the OP it’s quite clear that optimizations can be made on production and consumption side. And in their circumstances financial reality says that increasing production is much cheaper, while possibly providing extra cash that would enable investment for reducing consumption, which in turn would lead to more income.

> I wish you would expand and clarify the point you are trying to make.

The problem with people enthusiastically proposing renewables as the cheap solution to our energy needs is the thousand "little" details like the one above. Whose only mention is in the comments like "your math is wrong, invest in insulation".

No. The math isn't wrong. Bo, the consumption is correct and shouldn't "should be lower". Because it's directly indicative of the reality.

Yes, you have a couple of enthusiasts who can sink another X kiloeuro into rebuilding their house. For the absolute vast majority of users it's not a viable option.

So yes, the answer to "PV energy is almost enough in summer and not nearly enough in winter" isn't a dismissive "you're doing insulation wrong".

Also https://news.ycombinator.com/item?id=32201039

Venting is fine but but is there a point you are trying to make? Besides the "some people blah blah" strawman?

I shouldn't put solar panels on my roof because it would not fix someone else's problems? What kind of logic is that?

I think they're trying to say that insulation (and probably other factors) is not just one person's problem but an issue of a huge scale, which is true. If solar works for you, then that's great, but for a lot of people (the majority?) it wouldn't work, or at least not without spending a very large amount of money to retrofit your house for it.

I think it's a good point even if stated quite poorly.

Let me put it this way: is me having solar panels making things worse for "the majority"? If so, how?

Because it sounded like the usual trope that if a solution does not fix all problems for all humans everywhere, than it it sucks and the person doing what they can is a naive fool, if not a straight up villain.

That is a very strange question. Who in this discussion has said that you having solar panels will make it worse for the majority?

What comments in this discussion are saying is that solar panels won't be cost effective, for some or possible the majority of people.

I was responding to a very specific comment.

As for cost effective - subsidies. Big fat subsidies, especially for the poor countries. There are more important things than cost effective. We're all in this together

Cost is not really a valid reason not to pursue renewable. We need to switch to renewables no matter the cost, so as many people can survive as possible, and limit mass extinctions

> Cost is not really a valid reason not to pursue renewable.

If you have a money printer in the basement or free materials and slave labour, sure. In every other case it quite simply is.

> We need to switch to renewables no matter the cost

All true, but not relevant - we live in the real world where we make practical decisions. One of the aspects of that is not spending more than you have (for example so you can still eat).

Well in Germany at least they have legislative requirements for insulation on new builds (and have for years).

So that's an actual solution to the problem!

true, except most people don't live in new builds. As explained in other comments here, adding insulation to old buildings is highly non-trivial.

Thanks for the nice summary! I couldn't phrase it better.

How is this a tiny detail. We live in a passivhaus. We hardly ever heat. Improving insulation of old houses is an important aspect here. Reducing energy consumption is as important as generating and storing energy.

The point is that in some situations it can be more cost effective to generate additional energy than implement energy saving measures such as insulation improvements. My house was built in the 1600's it's very difficult to insulate properly.

Real Question: I see posts like this often on HN. Why not tear down these houses and rebuild with energy efficient ones? I know... blah. blah. blah. historical this and that... but do you want to suffer from 40+C summers? This is the price of history! Think about it. Really really! Please start tearing down these horribly inefficient houses that are "historical". We already do it for office buildings!

The issue is that it's ridiculously expensive. You have to pay an inflated price for an existing, perfectly fine home. Then you have to pay to have it demolished. Then you have to pay to build a brand new home. It's going to cost >2x what the resulting home is actually worth.

When the old homes decay to the point that they need to be torn down, then they will be. But destroying perfectly good houses is just too expensive in this market.

> Reducing energy consumption is as important as generating and storing energy.

Only if the efficiency is 100%. In practice it's lower than that, so reducing consumption is better than increasing production.

The point is not that everyone should live in a passivhaus. The point is that better insulation can help reducing energy consumption. Not best: better. Those are two different words. No, you don't need a passivhaus, but the passivhaus example, which barely needs heating, is useful for demonstrating the efficiency of insulation.

> The point is that better insulation can help reducing energy consumption

Yes, that's a wonderful tidbit that fans love to say.

It's also about as relevant to the discussion at hand as giving tips of how not to spill your coffee on the deck to keep it dry is to a sinking boat.

You can't solve climate change with better insulation. Sorry.

Part of the problem with the discussion about climate change is that people who've never actually looked at the numbers feel the emotional need to take the position of an expert and explain what will help.

And yes, if a car is rolling down the hill at you, at some level, technically, throwing a grape at it will slow it down.

But not enough to matter.

When you take the time to put your solution in the specific context of the discussion, and take a look at how big the impact is, you realize "oh wait, no, this actually isn't a valid line of thought."

You might as well try to solve the national debt with a ten dollar bill.

You're missing way, way too many zeroes.

In order to stop climate change, we must go carbon negative. Energy reduction does not change carbon dynamic spread, and cannot solve the problem without reducing our energy spend to zero.

I enthusiastically recommend that you read some work by the academics before continuing. These are not new ideas, and they have been roundly and thoroughly debunked for decades.

It turns out that yes, we have thought of insulation. This was not a curve ball. Owens Corning has so thoroughly advertised it to us that by the time I said their name, we all shared a memory of their mascot, its song, and their theme color.

There is a reason that absolutely nobody who's got actual traction in the field is offering improved insulation as a solution.

The reason Passivhaus is a good example is simple: they claim a 90% reduction in carbon, and when they tried to get LEED certified, LEED said "actually you increase carbon, we're not certifying you."

You're listening to marketing, and trying to hold it up as engineering. Every time you attempt to google for this, please do yourself a favor, and check whether the text you're looking at is word for word identical to their marketing materials.

Try a university study. None of them say it's a benefit, and there have been tons.

Respectfully, no, weird houses that make carbon worse aren't going to fix this either. Thanks for understanding.

A lot of what you typed have nothing to do with my answer. You also seem to be making a lot of very uncharitable and unpolite assumptions about me that don't make sense at all, since I only posted one single message, so I'll assume you're under the impression that I am someone else. Sorry but I won't be dragged into an internet argument.

Seems like every time extremist solar fans try to say "I don't understand why everyone doesn't just do it my way, which doesn't work unless you engage in exotic housing outside of cities," and someone points out why that doesn't actually work, they take it like a personal attack

I don't see why you're trying to claim I'm an "extremist solar fan" here, when all I did was trying to clarify what someone else meant.

I seriously hold no dog in this race but you're literally calling me a radical... maybe you're confusing me with someone else?

I lived in a new house for 5 years from 2016. We keep the house warm (21-22), but even then the radiators were rarely on, insulation was great.

On the other hand in summer temperatures overnight we’re still in the 28-30 range in the west facing rooms even at midnight.

I don't see how this relates to this discussion other than by spamming this subthread.

I appreciate that you don't see how a direct answer to your question, where you asked what you don't understand and it was spelled out for you, doesn't relate to the discussion.

I agree, your attempt to make the world's energy problems about the way you live personally in a Passivhaus doesn't relate to this discussion. That was kind of my point, as well as the point of several other people who've replied to you so far.

You might as well ask why everyone doesn't just live in an igloo. It's because they don't work in the places that most people live, like downtown. And if you try to ask the company "hey, I see that you claim you reduce carbon by 90%, why wouldn't LEED certify you, they only require 30%," the company will quickly change the topic.

I'll try it a little differently.

"If your solution doesn't work for 99.99% of humans, your solution just doesn't work."

No, I wasn't selling anything. This wasn't spam. But, you knew that.

I was making a good faith attempt to answer the question you asked.

Not sure how "better insulation" is something "renewable enthusiasts conveniently forget". We need better insulation either way.

I think what this person meant is the renewable enthusiasts treat insulation as something easily done whereas it will take 100 years to insulate the majority of houses in Europe in my view…

I know you are just illustrating an opinion and not meaning it literally, but I want to stress how ridiculous your number of 100 years is in reality.

The expected economic lifetime of a building in Germany is approximately 100 years. Which means that on average, the house will be torn down and rebuilt after at most 100 years, because additional upkeep would not make economic sense.

This means that if you do not change policy except mandating modern standards for new buildings (which is already done) and do literally jack-shit, the normal economic activity will have the problem sorted out in that timespan.

For reference: Of 22 million buildings in Germany, "only" 12.5 million are built before 1977.

The German government aims at having pretty much all buildings energetically renovated in 2050.

The biggest problem is that 1. there are many house-owners who literally do not give a shit even if they can save lots of money by an investment. Not everyone is economically minded and there is no political will (or legal basis) to force these people for their own good. And 2. for bigger apartment buildings etc. it is hard to do an invasive renovation while the units are occupied, limiting the scope of renovations to something that can be done in-place or one unit at a time or without affecting tenants.

>The expected economic lifetime of a building in Germany is approximately 100 years

Source?

Counter examples: my house is built 1908. Lots of other houses built around the same time in the area I live in. My parents live in a house from 1749. The entire village where they live is made of houses built 200+ years ago, it's written on the house in general, hence easy to check.

Hence I very much stand by my prediction it will take 100 years to isolate the vast majority of houses in Europe. Of course it's just a prediction based on my observations, I'm not an expert in the area.

The person you responded to was talking about the whole of Germany. You're talking about one individual village.

Your sample size is too small to make generalisations.

What sample over whole Germany? There is no source, no sample, it’s a baseless statement.

> Source?

Assuming an economic lifetime of 70 to 100 years for new buildings is industry practice based on standards like DIN 276. You can find those numbers (with some variation) on pretty much every web page dealing with economics of building, for example here: https://www.bauprofessor.de/wirtschaftliche-nutzungsdauer-ge...

You can also approximately extrapolate that number from the source I have given you. (Which is based on a survey by the federal government of Germany) If approximately 50-60% of houses are older than 50 years, then assuming a approximately linear to progressive attrition curve you will get a number around 100 for the average lifetime.

Of course a long tail exists, but 1. I was talking about economic costs, people might just like their houses and renovate even though it is financially not worth it, and 2. after 100 years the historical protection (Denkmalschutz) gets more and more relevant and is a whole different set of regulations.

I think you misunderstand what "economic lifetime" means here. It is mostly relevant for tax purposes.

In other words: if you build a house for $X and live in it then for tax purposes it is assumed that (on average) after a 100 years you must have been spending $X for maintenance so that you can sell the building for $X. If you have spent more money, then you can't deduct that from tax (exceptions exist).

Or in yet other words: if you don't spend anything for maintenance then after 100 years (on average) the building will be worth nothing, meaning that it will cost the same to rebuild it compared to fix it.

But since most people maintan their buildings, i.e. fix the roof when it starts leaking, fix the doors and windows when they break or are not airtight anymore etc., buildings are much older than 100 years. 100 years is the _minimum_ time before it's even worth to rebuild on average.

These maintenance tasks are exactly what this discussion is about.

You will do major work on roof or facades every 50 years or so. This is exactly the opportunity where you pretty much get insulation for free.

After 100 years the house will have been all but structurally rebuilt once, just for upkeep reasons. You perform energetic renovations together with the upkeep tasks.

And when the house is old enough, the monument protection agency will even force you to do it by that time.

Let me quote you:

> The expected economic lifetime of a building in Germany is approximately 100 years. Which means that on average, the house will be torn down and rebuilt after at most 100 years, because additional upkeep would not make economic sense.

This is just wrong. An economic lifetime of 100 years does not mean that the (on average) buildings will be torn down and rebuilt after at most 100 years.

And I have already explained why that is. Please read my post again and try to understand it.

> You will do major work on roof or facades every 50 years or so. This is exactly the opportunity where you pretty much get insulation for free.

No. This is also just wrong. Yes, when major work on roof or facades have to be done, this is usually the best opportunity to also improve insulation. But you don't "pretty much get insulation for free". Unless you have a very uncommon definition of "pretty much for free".

Mind that I'm not saying that insulation isn't worth it or anything like that. I'm just pointing out that some parts of what you are writing are wrong. And the sources you cited are not supporting your claims. That's all.

Please don't forget that my claim is in the context of somebody else claiming that insulating all housing in Europe would at least take 100 years.

Now you are literally redefining the terms I use and then quoting them back to me to argue your new semantics, are you serious?

On average, a house is considered to last 100 years in Germany. Call it economic lifetime or whatever else you want. I still stand by that claim, as it is common knowledge. I quoted specific numbers on the housing stock which are consistent with that claim (though no proof of causation, as there are plenty of reasons why we have a lot of new stock, for example in general rising number of buildings.)

And of course the insulation is not "for free", but the additional costs are usually worth it. I also mentioned that many people decide irrationally because they do not want the work associated with planning and ordering the maintenance to be performed.

None of this matters to show that the above mentioned claim how long renovation of the current housing stock will take is completely out of the world.

Note that I am by no means a civil engineer or architect, but following the discussion and researching the topics associated with the Energiewende in the different sectors for over a decade now. I may still well be wrong in this instance. But you won't convince me of that if you try to prove me wrong on semantics and just asserting that I were intellectually unable to understand your arguments. So please also state some relevant facts and sources to support your claims if you want to try further to convince me, otherwise continuing this discussion is probably a waste of time for me as we both will probably not learn anything new. Thanks.

> But you won't convince me of that if you try to prove me wrong on semantics > (...) > On average, a house is considered to last 100 years in Germany.

First please define what you mean by "last" so that we share the same semantics and then provide a source on this. And if you mean that a building will have been destroyed and rebuild after 100 years on average then I doubt this claim - after making such a strong claim I think it's up to you to provide evidence.

> I quoted specific numbers on the housing stock which are consistent with that claim

Are you referring to https://www.bauprofessor.de/wirtschaftliche-nutzungsdauer-ge... ? Because if you do, then again, you misunderstand what they are talking about. Also, don't forget that average house-ages are misleading due to WW2 where a lot of old houses got destroyed. So you can't e.g. just take the average age of existing houses, that doesn't work.

> And of course the insulation is not "for free", but the additional costs are usually worth it.

Look, I agree with you - but the way you said it before is so exaggerated and easy to misunderstand that it's no wonder that you are getting these kind of responses. This is a very emotional topic and it's good to try to adjust the language accordingly.

> I also mentioned that many people decide irrationally because they do not want the work associated with planning and ordering the maintenance to be performed.

It's easy to call someone irrational - but why do you think they don't want this work to be performed. How comes? I doubt that you assume they want the planet to die, so what do you think are their reasons?

> First please define what you mean by "last" so that we share the same semantics and then provide a source on this.

Le me just try to give a definition, "lasting" for me means that you only do maintenance and rework that you would still consider the building year to remain the same after you are finished.

Also the semantics of the term "lasting" were not the issue, the issue is that you do not my sources because you find the term economic lifetime and its definition unacceptable.

> Are you referring to https://www.bauprofessor.de/wirtschaftliche-nutzungsdauer-ge... ?

No I mean my number that approximately half of housing buildings are younger than 1977, so approximately 50 years.

This refers to a survey by the government, see box on bottom: https://www.bundesregierung.de/breg-de/themen/klimaschutz/kl...

Someone else in this thread posted a similar source from ourworldindata which has a bit older data but also shows the same trend.

The latter source also has a more detailed breakdown of building years. But even the former source mentions 1977 as its index year which already alleviates the external effects of WW2, people did not just live without houses for 30 years, the lost housing of WW2 was mostly rebuilt in the 50s.

Also, I do think that your claim is not valid. I do understand that the source I gave for economic lifetime, and also the norm I quoted is acting with fictions required for taxes and accounting reasons. The thing is: These fictions are intended to reflect reality. So I don't get why you are so hung up on where these calculation models originate, as they are specifically designed to reflect reality. If they were outlandish, especially when lifetimes on average are longer, these calculation models would absolutely be changed because then the state earns more money due to lower depreciation. If it was the other way around, the calculation model would be challenged in court.

Of course there is no natural law that a house collapses after 100 years. But not only in architecture, in all of engineering, it usually does not make sense to design for an infinite lifetime. If you double the lifetime of anything, it will cost a lot more money. Why would you spend more money today to build a house with better materials, when you don't even live to see the rewards in the form of lower maintenance and renovation costs in a 100 years. By extension this applies for the amount of money you want to spend in maintenance, at least for natural persons. In many situation it makes sense to simply use up the bound capital.

Now this leads to the following:

> It's easy to call someone irrational - but why do you think they don't want this work to be performed. How comes? I doubt that you assume they want the planet to die, so what do you think are their reasons?

As an anecdote for illustration, my grandparents still heat with oil, but the heater soon needs to be replaced. My grandparents are absolutely stubborn in that they want to replace it with a completely new oil-based heater. The literally only reason is: They are old and don't want to try out something new, even if it is functionally exactly the same (like a wood pellet heater). I literally offered them to pay 100% of the new heating system (reversible heat-pump because heat is one of the primary killers of elderly people and I would like my grand-parents to be around a bit longer...) after they bought heating oil on the ATH this spring and they still disagree. There is literally no economic incentive of looking the gift horse in the mouth, and they are unable to offer any other rational explanation.

You may also skimp on maintenance because you think "I am going to die soon anyways". Or people are planning to be living in a large 200 square-meter mansion with 3 stories until they are 90 when in reality they sell the house at 60 and suffer the loss of value when re-selling due to insufficient maintenance.

And some people just want to live in their house and don't give any thought to it until there is an emergency. Then people will have expensive repairs and still won't think twice about changing their behavior.

Some small house owners skimp on maintenance because they bought their houses as an "investment", and they are dependent on rent income to reliably subsidize their life. Even when the income could be higher in the future with some investments and quickly ROI, they won't accept saving up for it and taking on the economic risk.

Even for institutional housing owners it makes sense to tear down units eventually, even if it is just to get rid of the long-term tenants who make larger renovations annoying to impossible.

There is a lot of small house-owners and in general, most people are just really bad at basic accounting. This is also a big reason why the housing market in general is such a pain in the ass.

> But even the former source mentions 1977 as its index year which already alleviates the external effects of WW2, people did not just live without houses for 30 years, the lost housing of WW2 was mostly rebuilt in the 50s.

It does not sufficiently alleviate the effects of WW2 and other developments.

For instance, the population got reduced to 82% due to WW2 [1]. Also, living space per person has increased a lot over time. I can't find a source for 1945, but here is one from 1971 to 2014. The number of squaremeters per person has almost doubled during that time. [2]

So no, people didn't live without houses for 30 years. But they needed/used way fewer houses overall.

[1] https://de.wikipedia.org/wiki/Liste_der_Volksz%C3%A4hlungen_... [2] https://option.news/wohnraum-im-wandel/

> Also, I do think that your claim is not valid. I do understand that the source I gave for economic lifetime, and also the norm I quoted is acting with fictions required for taxes and accounting reasons. The thing is: These fictions are intended to reflect reality. So I don't get why you are so hung up on where these calculation models originate, as they are specifically designed to reflect reality.

You are misinterpreting them. They don't literally say "houses are worseless on average after a 100 years". They say "houses are worseless on average after a 100 years without doing anything to increase their value". And this is certaily more or less accurate. However, most people don't just let their buildings rot. Some do, but most don't that's why buildings are on average not being rebuilt after a 100 years.

> Why would you spend more money today to build a house with better materials, when you don't even live to see the rewards in the form of lower maintenance and renovation costs in a 100 years.

I find it a bit offtopic, but a very common example is that parents want their children to inherit it so that they don't have to worry about rent or can rent it out for some extra income. Other examples include people who don't necessarily want to stay in the house forever but want to increase the value to sell it later to a higher price. Some people also just enjoy building something that lasts (I am one of those). I think you can agree with that, no?

> My grandparents are absolutely stubborn in that they want to replace it with a completely new oil-based heater. The literally only reason is: They are old and don't want to try out something new, even if it is functionally exactly the same (like a wood pellet heater). (...) and they are unable to offer any other rational explanation.

First, let me say that I understand how you feel about that. I know the situation and sometimes it pains me to see what people do. I would have adviced the same as you. However, without knowing the situation, I think that sometimes in these situations the problem is safety concerns.

The fact that they are unable to "offer any other rational explanation" really makes me think that there is quite the chance that they do have a reason and they are just tired of providing it. If I had to make a bet, I would say they had some bad experience with modern technology in one way or the other. And they maybe also know a time where the winters were cold and heating didn't work. They do not understand heat pumps (not even I fully do) and they are afraid that when something stops working, they are helpless. For them, it feels like a total lack of control over something that is crucial to their life. But would you accept that answer? Probably not. Maybe they already hinted at it - try to remember if they did that and if you properly acknowledged their fears. With oil, not only do they use a technology that has worked for a long time and is much more well understood by them - it actually also makes them more independent of restrictions to power/heating compared to other solutions - at least as long as they have a full tank.

Unfortunately they could very well not be irrational but very rational when considering their situation. Is the decision good? No, I don't think so. But it is not irrational.

Of course, maybe I'm totally wrong. But it wouldn't be the first time that I see a conflict like you describe.

In the end, let me give you some advice to your situation. If you think that it could really be feeling of control and safety that makes them stay with oil, then how about offering them to install an aircon? Aircons are heat pumps as well, and very efficient ones as well (usually more efficient than air/water heatpumps). They can keep their oil, but the aircon might make it able to reduce the oil consumption by a huge chunk, depending on the circumstances. It doesn't cost too much and you even get BAFA Förderung. And on top of that, you can use it to cool/dehumidify of course - heatstroke is also a common reason for elders to end up in hospital. That solution is what I would try in your situation.

> And some people just want to live in their house and don't give any thought to it until there is an emergency. Then people will have expensive repairs and still won't think twice about changing their behavior.

This is not irrational, only lazy. Irrational means to do something even though you know it's wrong. E.g. out of a mood.

> It does not sufficiently alleviate the effects of WW2 and other developments.

Remember, we are still talking about the claim that renovation of the building stock takes approximately 100 years.

It does not matter whether we are building more because people need more space, or because houses are actually replaced. All that matters is that the percentage of the building stock built under modern energetic regulations rises sufficiently fast.

This is why this discussion is so frustrating for me. It's all about semantics that don't matter, when my point was actually just disproving a point I thought to be ridiculous (which with the new research I did for my rebuttals was actually sort of disproved, as Germany seems to be really good at renovating the building stock compared to e.g. Eastern Europe), which is also why this will probably be my last post in this thread.

> You are misinterpreting them. They don't literally say "houses are worseless on average after a 100 years". They say "houses are worseless on average after a 100 years without doing anything to increase their value". And this is certaily more or less accurate.

You seem really hung up on the topic of depreciation accounting (AfA) and don't seem to get my point. Depreciation is regulated and does not exist in a vacuum.

Depreciation is a legal fiction to model the reduction in value of assets in such a way that it is easy to calculate, but also close to the actual value that would be fetched on the market due to the depreciation.

You are essentially claiming several things with your argument: 1. depreciation is not correlated with actual value loss, and therefore 2. the economic lifetime model used to calculate depreciation does not correlate with actual use lifetime.

The first is correct: Renovation expenses can be used to raise the book value of the asset making them balance-neutral. The second is not and especially does not follow from the first for the reason that I told you, the lifetime model used in depreciation calculation is based on the observed lifetimes in reality. There is also feedback in the other direction as engineering decisions are taken based on the best practices in economic lifetimes, which is why I cited the relevant DIN norm for cost calculation for builders in my first post.

> That solution is what I would try in your situation.

Thanks for your advice. But I already tried that. And it's pretty funny that you literally try to explain the mentality of my grandma to me. But what do I know it's only my grandma.

Let's just let the topic rest, I do not really care about this discussion anymore.

> Assuming an economic lifetime of 70 to 100 years for new buildings is industry practice based on standards like DIN 276.

Sure, but that wasn't the standard 100 years ago. There are plenty of existing houses that are 100+ years old that will continue to stand for at least another 100 years.

Your parents house was built in 1749. Do they pay the equivalent carbon tax to own a house like this? Unless it has been hyper-modernized, but the exterior remains old/ancient, I struggle to understand or support your argument.

More brutally: If you parents want to live in a house from 1749, should 1.5 billion people (probably more!) in South Asia be forced to live in unsustainable conditions (much high average annual temperatures) for the "history" of your parents' house? Absolutely not.

In contrast, if you support massive gov't subsidies and personal taxes to pay for the upgrade of these homes to 21st century energy standards, then... sure, no problem, they can live in a home from 3000 BC!

You missed my point. I was saying that 100 years max lifecycle for a house is wrong in my view.

Europe is a big continent, even EU is so diverse.

A lot of people in Eastern Europe live in apartments and houses that can be insulated extremely cheap. There are even EU or government programs that make it affordable.

It's not really "extremely cheap" and probably only refers to covering old buildings with external insulation.

Most of the Soviet-era panel apartment blocks (https://en.wikipedia.org/wiki/Panel_building) have extremely shitty internal insulation, too. So you end up heating your neighbors, the street, the elevator shafts, stairwells etc.

You can't really fix that without extremely costly renovations.

Khrusschchyovkas (https://en.wikipedia.org/wiki/Khrushchyovka) are marginally better due to materials used, but they are 50 years past their demolition date by now, and will be also very expensive to retrofit.

There is also an insane number of new construction in the past 30 years. Perhaps for the in-EU Eastern European countries regulations and standards work. Everywhere else it's "whatever we build, as cheaply as possible"

I think having some insulation is better than having none. But yeah, if you want to do it properly, it would cost a lot more.

As for heating your neighbours, a lot of cities have city heating and is paid depending on how many people live in the apartment, so you don't care that much about it. Of course, some folks have gas boilers in their apartment (like me) but it won't make sense financially to insulate the inner walls.

I think it's the same for new buildings here too, if not worse. A lot of regulations aren't actually respected and because a lot of builders left for WE, there's a huge problem with finding skilled workers.

> Not everyone is economically minded and there is no political will (or legal basis) to force these people for their own good.

Not for their own good, but for the common good sure there is a legal basis. Eigentum verpflichtet.

Same direction as mandating solar panels for roofs.

What I mean with legal basis is that the laws do not exist yet.

The constitution would allow these laws, even to the point of expropriation. But as long as the laws do not exist there is no legal basis to act on.

In case of conflict, there are some court rulings already, for example the highest court recently ruled that you may infringe on the neighbors property, if you need to insulate your walls in such a way that the thicker walls would then be on the neighbours property.

Much of eastern Europe, so not particularly rich or well run countries, went from zero (due to cheap Russian gas in Warsaw pact) to ~everything insulated (because trying to cut dependency on a mortal enemy) in less than two decades.

I'm from Moldova. No, they didn't go to "everything is insulated" even in the wildest dreams.

The EU paid for lots of insulation here in Bulgaria. Mostly blocks of flats, of course. They were ugly and really needed it. Hope you guys enter the union soon

> it will take 100 years to insulate the majority of houses in Europe

Citation needed. This number is absurd.

500 million people.

So, around 200 million or so households. Each household (even if it's an apartment) needs both external and internal insulation improved.

Same goes for things like stores, factories, schools, government buildings, and all other non-residential buildings.

Most buildings are built before new energy standards (https://ec.europa.eu/energy/eu-buildings-factsheets_en). In some countries (esp. the Eadtern block) you probably need to teardown old buildings because you can't just simply insulate them (https://news.ycombinator.com/item?id=32202169)

I'd say "100 years" is a conservative estimation

Except the large majority of buildings are not going to last anywhere close to 100 years, and they will be very likely be replaced with better buildings long before that.

And most of the buildings that instead have a lifespan beyond 2122 are historical buildings built with very thick walls and they don't need insulation work beyond replacing windows.

There are many statistics on building lifecycle that you can easily find on the Internet.

So such estimation is really not grounded in reality.

> Except the large majority of buildings are not going to last anywhere close to 100 years, and they will be very likely be replaced with better buildings long before that.

We need a quote on that. And no, "bulidings last on average 100 years without doing anything to them" is not it.

"Replaced with better buildings" inevitably means "displacing large swaths of population". Because you can't just wave a magic wand and replace houses. For the past 4 years I've lived in a district built in th 60s. So, 60 years ago. If you're telling me that those dozens of building with hundreds of people living in them will be just up and replaced, you're delusional.

No one can reliably predict this, this is my opinion simply. I thought that was clear.

Thank you. I couldn't have phrased it this well

You can usually improve insulation by popping down to the local DIY store and buying some rolls for your loft making a big difference.

Of course you can only do that once. And if you’re a landlord why would you pay your money to insulate when you wont save any money as your tenants are the ones paying the bills.

Have you ever heard of mould? Moisture in the walls? Caused by shifting dew points. Your "just pop down to the hardware store" DIY insulation will do a lot of damage.

In some countries, you can't rent out homes that fall below a certain standard for insulation, and the efficiency is rated as part of every property sale, which internalises the cost savings and makes it worthwile.

> With all due respect these are the kinds of "tiny" details that renewable enthusiasts conveniently forget.

I mean generally it is well known that you cannot just put a lot of PV/Wind and things will work. A smart grid is needed, buffers and ideally great insulation although that is arguably important for every form of energy. Also at-home PV setups are meant to earn money/offset the energy bill. Autonomous energy supply is an after-thought that is interesting enough but has obviously not been possible with any other energy source before actually.

Well yes, but generally renewable enthusiasts are also saying "we need to improve our housing stock". That's another of the opportunities to improve people's lives that will come through necessary change.

surely 'improving housing stock' will require a lot of energy expenditures that might not be easy to calculate what the actual benefits are.

Housing energy models are well established - things like PHPP, which though a bit of a dog to use is well validated and cheap. Low and negative carbon techniques are also available - things like mycelium insulation, which notionally outperforms EPS (and even that pays for itself from a carbon perspective very quickly if used properly).

You make some good points in the middle of the edgy writing, but how do you think people get to the point of proving out new technology?

You'd be shouting at the magic black gold people too back in the day. How would it light people's houses and require a full grid installation, and fires and blackouts, when candles already fix the real world problem.

In a worst case scenario (no gas, no grid electricity), he could heat only one room instead of entire house.