We just refurbished our house here in Norway. New windows and 10 cm extra insulation. I am shocked how well the windows perform! Ice on the outside, but nice and warm on the inside. Amazing!

It's a different world. The amount of "fyring" (burning wood on the stove) we had to do before we did the renovation of the house was nuts. Also the "vindsperre" works pretty well.

It's a bit annoying with new windows that they perform so well that you'll get dew or ice on the outside a lot of the time.

Supposedly, windows with an outer self cleaning layer get less condensation, but they're quite expensive.

I expect I would consider that charming, but I can imagine it gets annoying after the first week

My windows do that - I still think it's pretty fun even after some time.

Better than the dew and ice of the inside like with single pane windows!

That sounds like the problems that happened when they switched traffic signal lights from incandescent to LED. The incandescent lights put off enough heat to keep all the lights defrosted and visible, while the LED versions could be blocked by heavy snow/ice.

TIL quadruple glazing is a thing. Is the light noticeably more attenuated through 4 panes of glass compared to 2 or 3?

It is a little worse than that: some triple glazed windows are intentionally made more opaque/green tint for 2 reasons: 1. easier on the eye when sunny outside, and 2. block up to half of solar radiation, to prevent overheating indoors

does Norway worry about overheating indoors though?

Not sure, but consider that summer months can have little to no nighttime owing to the northerly latitude.

that's true, it does get hot sometimes in Denmark where I am, but then I open the windows when that happens.

My experience is it's either too cold to open the windows, or you will want the windows open - in my part of Denmark.

I'm not in Norway, but here in Finland I don't appreciate having nearly 30C indoors in the summer.

I don't think it was much of a problem historically, but anecdotally the summers have been getting worse* over the 15 years that I've been here. I finally had to break down and buy a portable air conditioner a few years ago.

*Some people enjoy having more hot days during the summer, of course.

In triple and quadruple glazing, you frequently don't get three or four layers of actual glass. The two outer layers are still glass, but the inner layers are usually thin sheets of plastic, and the voids are frequently filled with noble gasses like Argon for improved insulation.

Although I have seen in Alaska where they do double glazing windows on the outside as storm windows, then about six inches to a foot inside of that, they have another layer of double glazing. Yes, the walls are super thick.

>>and the voids are frequently filled with noble gasses like Argon for improved insulation.

How long is such a window rated for? Surely the gas will eventually leak out?

Not really a problem one would be aware of. Double glazing is the default since 50 years at least in Germany, so the manufacturing processes are quite good.

Still, leakages happen, you recognize that usually by water/steam between the two glass panes. If the windows aren't to old you can just switch out the glass leaving the plastic frames. If they're older (30 yrs) it's more economical to switch out glass and frames.

Almost all my double glazed windows have now failed and I'm looking at replacements, but my fear is that the failures are due to the amount of vibrations this house gets (I'm close to a busy road, every time a lorry goes past I can feel it in some rooms).

From what I can find, the leakage is estimated at < 1% per year. This (German) discussion references and quotes the (German) industry standard DIN EN 1279-3.

https://www.haustechnikdialog.de/Forum/t/65875/Haltbarkeit-A...

Leakage rate is ~1% per year. However the gas isn’t so important you need to replace the window as argon is only up to 16% better than air.

It’s worth it to manufacture windows like this, but unless you’re in the arctic circle I wouldn’t worry about the difference.

There’s been so many window manufacturer lawsuits over this issue that my guess is a manufacturing defect.

Properly constructed, I think these windows are expected to have a useful lifespan of at least 20-30 years. I think the heavier gasses are less likely to leak, so long as the window is kept intact and undamaged.

I'd expect the insulating properties of a gas at normal temperatures and pressures to depend only on the molecular mass. That's 40 for argon, and 28 for nitrogen. This web page (https://www.pressglass.com/noble-gases-and-thermal-insulatio...) says the thermal conductivities are 0,026 W/(mK) for air and 0,018 W/(mK) for argon. 26/18 is about 1.44; 40/28 is about 1.43. So perhaps the conductivity is inversely proportional to the molecular mass? In that's true then it's not a "noble" gas you want for improved insulation, but a dense gas (so not helium). You should be using tungsten hexafluoride! OK, not really: see https://en.wikipedia.org/wiki/Tungsten_hexafluoride for why not.

The heat capacity of the gas depends on both mass and molecular structure. Atoms like argon have no structure, but molecules like O2 and N2 carry extra heat energy in their vibrating bond, so they have more heat capacity per unit mass.

That's a good point. Perhaps the result of that argon/nitrogen comparison was a coincidence, or perhaps heat capacity doesn't much affect thermal conductivity.

Here's an argument that heat capacity shouldn't affect thermal conductivity in a solid: imagine a block of material with a smooth temperature gradient through it and the temperature at any point remaining constant, so there is heat flowing through it. Now imagine you have some tiny beads of some other material with a super-high heat capacity. Distribute those beads throughout the block of material, preheating each bead to the correct local temperature before inserting it. Then intuitively it seems that neither any local temperature nor the rate of flow of heat through the block should change much. Yet the heat capacity of the new composite material is significantly higher than that of the original material. Does that argument make sense? I did physics at school but not since then!

Yes, I don't think they're strongly related in a solid.

But in a gas, heat transfer is mostly driven by convection. Gas near the hot surface heats up, rises, moves to the cold surface, falls, and repeats. So what matters is the specific heat capacity * the flow rate between hot and cold surfaces.

Thanks for that explanation. So the "thermal conductivities" I quoted above, if they don't take account of convection, are perhaps not even particularly relevant. The advantage of argon over nitrogen might be greater than those numbers suggest?

I'm not exactly sure how they choose which particular gas to use, but I'm sure the lighter gasses will leak more easily.

Conceptually, it's like a thermos bottle, and you'd think that you would want a vacuum, but apparently that's hard to keep intact on windows, so a noble gas between the layers works better.

Yes, but not any old noble gas. Helium and neon, for example, have higher thermal conductivities than nitrogen. So it seems like argon is better for the job as well as being cheaper.

(While every noble gas has roughly the same heat capacity by mole/volume. Perhaps some CFCs would have been even better for insulation, but bad for the ozone layer, of course, and rightly banned?)

That probably depends on where you are. Here in Amsterdam, our triple glazing is made out of all actual glass. In our house it’s made out of four 6-mm sheets of glass actually. So one double sheet that’s a sandwich with a glued layer of foil in between (like a windshield), used as a security component either on the outside (anti break-in) or on the upper floors on the inside as a way to prevent falling through the window.

Having more layers of actual glass helps with sound insulation also, probably more of a concern in Amsterdam than in Norway.

6mm sounds very thick?

Probably meant 6 mil (1mil = 1 thousandth of an inch), since this is a typical non-metric measure of sheet thickness (metal, glass, plastic).

Yeah, I'm sure it does depend on where you are.

For the nearly eight years that my wife and I lived in Brussels, Belgium, we lived in an old house (rented) that was built around 1910, and so we didn't have even double glazing, although we did have French Doors, and we had custom-made screens that had to be manually placed into the windows and then pinned in place with a nail instead of always attached to the outside. So, I don't have much knowledge of what current European building standards are in this space.

I do prefer the German-style double-opening windows that I saw in the house my sister-in-law was renting near Spangdalem AFB, along with the Rolladen that they had installed. But again, that was a rental in an older home.

I have been watching Laura Kampf and her "Haus Lise Lotte" project on YouTube, but again that's a 120 year old house, and they haven't gotten to replacing the windows yet.

Any suggestions for an English language channel where I could learn more about current European building standards, maybe something like Matt Risinger's "Build Show" for US building standards that I've been watching on YouTube?

It's all about the UK but Grand Designs often features builds that have technology and equipment from the continent.

Somehow I’d thought the voids were usually evacuated but that doesn’t really make sense with the pressure involved. Apparently it is possible to have a vacuum inside but uncommon and harder to manufacture (and you need support pillars to separate the panes). https://www.glassonweb.com/article/vacuum-insulating-glass-p...

You'd still have radiative heat transfer, even if there is a vacuum between the panes. For a given budget, you're probably better off adding more regular panes.

Aren’t new windows often coated with something opaque to IR, that way they keep heat in during winter and don’t heat up like a greenhouse in the summer?

Those are low-emissivity coatings. Very effective in reducing radiative heat transfer. This is why the glass in a vacuum flask is silvered: metals have low emissivity. These coatings aim to have low IR emissivity while still allowing visible light through (IR light gets reflected, instead of absorbed/emitted).

My point was only that a vacuum gap is still not a perfect insulator, so it's an economic trade-off.

> Is the light noticeably more attenuated through 4 panes of glass compared to 2 or 3?

I don't notice a difference now that I have two double glazed windows on top of each other (kobla vindu - I don't know the English word for it), I'll include a picture here:

https://spesialvinduer.no/wp-content/uploads/2019/08/Skaara_...

>kobla vindu - I don't know the English word for it)

In the UK we'd call this secondary glazing if I'm understanding the image correctly.

OK, an absolute nightmare to clean though. 4 surfaces on each window; and dirt/insects etc. can sneak into the space between the windows. But they look old cool and authentic I guess :-)

It is really hard to tell when every window is of the same dampening. But yes, I guess they lose some light.

There are even products with 6 panes.

Edit: one such product http://www.reflex.si/en/q-air

In the US the rating associated with this loss is called Visible Light Transmission, or VLT, and it can be quite low by percentage, especially in ‘Low-E’ windows designed for sunny climates. The nature of our perception of light intensity means that the use of a percentage of transmission might not be the best measure for the effect. I feel like something like the geometric scale of the f-numbers used in cameras would be more appropriate for how the change in light intensity feels, which I think is the intent of the VLT factor as there is also a Solar Heat Gain Coefficient (SHGC) that relates to the performance of the window in that regard.

Low-e windows are not just for sunny climes - it's arguably the dominant benefit of modern windows. Interestingly, when you put low emissivity layers on each pane, it doesn't matter whether it's pointing towards the inside or the outside. When pointing outwards, it reduces the propensity to radiate outwards, when on the inside it reduces the propensity to be heated by radiation. More layers are good because that increases the number of low-e layers you have - with double glazing, you only have two on the insides; with triple glazing you have 4.

I don’t think you can generalize quite that much - on buildings in heating-dominated climates, low-e windows and their accompanying low SHGC result in rejected solar energy that could otherwise be used to heat the home by day. Without proper shading, overheating can be a concern in fall and spring for south and west facing windows but in my understanding north facing glazing shouldn’t be low-e in any heating dominated climate.

Here in South Africa, single glazed is still a thing. I've been replacing all my windows with double glazing. I considered triple but that makes them very heavy and expensive. Benefits are both in hot summer and in the relatively cold winter.

Where in South Africa? I would guess that along the coast the weather is never extreme enough for this to matter all that much?

Different South African here, but I grew up in Durban and now live in Cape Town, with regular visits to Johannesburg (2-4 times a year). Single-glazing is used in all three by default, despite the climate being quite different in all cases. Durban is tropical; winter (we joke that it doesn't have one) is dry, and summers are wet, but its warm year-round. Temperatures can vary quite a bit between seasons in Joburg and Cape Town. Cape Town has a Mediterranean climate; summers are warm and windy, while winters are cold and wet, often getting to 7°C at night (it's a cloudless 25°C summers day today though). Joburg can get a little colder, although its a much more dry kind of cold.

Cape Town. It matters a lot... actually, imagine 5C or even 10C outside and that cold just coming straight through the windows. That means you'll be freezing inside. In summer it also seems to help. Yesterday was 36C here and we had 25C indoors, which would had been much worse if we didn't have roof insulation and double glazed windows.

My house in Australia is all single glazed. But where I live summers aren’t that hot (rarely over 30c) and winters aren’t cold (rarely less than 10c overnight). I’ve considered double glazing but it makes no sense really

You will save on heating, though. If it's 10C outside and that cold creeps in, it's going to be pretty cold inside unless you run lots of heaters or a fireplace all the time.

Not everyone is bothered by this though, but I think a house should have at least 21C in winter.

In Sweden, because of the crazy electricity prices, everyone is discussing right now how warm they should keep their houses. The idea is that a good citizen should save energy and therefore let the house get colder (also, to be "green" of course - but nothing like 5x more expensive energy to get people saving). They asked some politicians, most of them were saying between 19C and 21C.. one guy even said 15C, which everyone thinks is BS :D

Discussion of what temperature a house should be is preposterous. A well-insulated home would obviously use less energy to keep a comfortable temperature than one with drafts all over.

Discussion should focus on energy budgets or total energy use, but that may be hard to conceptualize for the average Sven.

It's all about appearances. Everyone is now driving Teslas and electric Volvos. It's easy to make "efforts" when it shows your "virtuousity" or at least in your head, makes others admire you. You're never going to see rich people moving into much smaller homes that require 1/10th the electricity, which would actually contribute much more significantly to avoiding climate doom.

In Minnesota, New York, and some other places in the USA, 16C indoors isn't uncommon. I turn the heat down at bedtime and my room will be 13C when I wake up. But we're crazy and just like to prove we're tough, so...

You should mention that Australian single glazed windows are also very easy going on all other aspects of the window and it's tightness to air/wind. At least the older ones.

I was never as cold indoors as in Australia. The houses have no insulation, it's almost as cold inside as it is outside. Even if it's above 10°C in Sydney in winter, it's about 15°C indoors unless you use AC for heating. Add to that just terrible craftsmanship of walls and windows.

American in Australia - the house quality, even if the building is new(er), is absolutely shocking. I'm contributing to climate change with all the heat/cool bleed from my rental. Where I never even thought about the electricity bill from where I am in the U.S., I'm spending anywhere from $60 to $250 a month depending on season, where the anecdata average is actually 2x or 3x that.

Thankfully two or three years ago, we signed up for amber.com.au which will give you real time pricing and alerts so we can be thoughtful about usage in peak demand.

I've been tracking usage via their API for ~two years

https://flatgithub.com/dalanmiller/electricity?filename=3121...

Why did you move to Australia? You must be out of your mind. Kidding, just wondering.

I moved for work is the simple answer. Came to find pretty quickly life in Melb is pretty great, possibly one of the greatest places to live.

I think the “quality” actually goes down as you get newer. They are better sealed and insulated yes but…not quality - especially project homes. I own an old house (1890s) and the craftsmanship of the original portion of the house is spectacular. The 80s extensions are horrible though.

I'm still amazed seeing "x panes" windows that are supoosed to be great with a "trinkle vent"/ aka adjustable gap - at the top of them to let air in/ out!!!

Exactly! I pleaded with the window company not to put vents in the new windows, as my house is already very draughty. They said it’s the law. They are cheap and poorly designed so they let in lots of noise too. And I had to tape them off because of the draught they let in even when closed.

A house does need ventilation. It's incredible how quickly humidity and carbon dioxide build up in an enclosed space from just breathing. The carbon dioxide is bad for you (reduces your ability to concentrate), and the humidity will have to condense out somewhere (on the coldest part of the house, which will usually be the windows, but wherever it is, it'll help mould to grow).

However, getting that ventilation using trickle vents in windows is just a stupid way to do it. You're letting all the heat vent out, and letting the noise in. A better way is with a mechanical ventilation heat recovery (MVHR) system. That sucks air out of some rooms (the bathroom and kitchen are recommended), and passes it through a heat exchanger before pushing it outside, while simultaneously pulling in fresh air from outside, heating it up in the heat exchanger (for free) and blowing it into other rooms (such as bedrooms and the lounge). This is the proper way to do it.

A MVHR system only really makes sense if your house is otherwise fairly non-leaky. However, if you do install it, then it can take over the bathroom and kitchen extraction, and it allows you to plug all those leaks and insulate well, without causing stale air problems.

My house has plenty. I’m very sensitive to lack of fresh air, so I would know. The kitchen fitters did a terrible job and left lots of holes in the walls behind the cabinets and the floor is extremely draughty. There are huge exposed air bricks to keep the timber dry which also causes draughts everywhere downstairs even with good carpeting. And it’s open plan from the kitchen to upstairs so those draughts make their way upstairs. I also live on a hill and get plenty of prevailing wind. I spend a huge amount on energy trying to keep warm - it’s hard to know which bits to tackle to keep warm but not to cause structural and other problems…

MVHR makes total sense and sounds superior. I’m sure the builders have successfully lobbied against such a sensible suggestion for decades and that’s why we have (I imagine) such stupid and basic solutions in our building regulations.

I feel like UK houses lack infrastructure that the likes of the US and Europe have. Even kitchen ventilation is such an afterthought

Nowadays, with lots of places being converted to be more "energy efficient", the interventions are typically:

1) huge thickness thermal insulation on the exterior

2) double/triple gaze (airtight minus the small built-in ventilations) windows

3) NO added mechanical ventilation

The bets are on on how long it will take for people to realize that if they do not vent manually the house humidity/mould will form.

This has already happened for houses built some 10-15 years ago (the first houses built as Class A or Class B) that - even if newly built - did not usually provide mechanical ventilation.

There are on the market since a few years small "in-pipe" mechanical ventilators, including a heat exchanger, basically you make a 100 or 120 mm hole in the wall and put in it a pipe that contains the vent and heat exchanger, they are very suitable to install "as an afterthought".

Trouble is that they work on "alternate cycle", i.e. they suck air from the inside for - say - 30 seconds (warming the heat exchanger), then they push air from the outside for another 30 seconds, and they may be (or become) noisy, new models have built-on timers to be able (as an example) to switch off at night if in bedrooms or switch off in the evening in the living room, etc.

I guess a ntuple-glazed window is going to have a lot less thermal mass than a wall (though presumably depends on the wall material too – thick stone walls will have more mass than wood+plaster). But I’ve little idea what the right amount of thermal mass is for a building.

Thermal mass is usually not a factor you're looking at when choosing windows; thermal resistance is.

In a nutshell, stone, concrete, metal, and glass are very good at transmitting heat, so the inside of your house will quickly be as hot (or as cold) as the outside. Plastic, wood, and especially air are very bad at transmitting heat (or good resisting to heat transmission) and this is what you want for your house. Back to windows, multiple sheets of glass are only desirable because they have an air chamber inside. Three layers of glass mean two air chambers, each at its own temperature.

I know how double glazing works but if you put a window somewhere then you aren’t putting a wall there. So I’m wondering if having a much higher % window (is less wall and more glass) will cause the building to have an importantly lower thermal mass. But I don’t really know if modern buildings would want a large or small thermal mass.

I’m confused by what you write about stone and concrete being good at transmitting heat. I thought the point was that (a) they act as an accumulator regulating the temperature because they take a lot of energy to heat up and (b) they conduct heat poorly (or worse than a window would be mm of thickness but they are much thicker) which is insulating.

Looking up random values from the web, it seems a the low numbers for a thin concrete wall (single wythe means no cavity insulation) are about 2.5x those of a coated double glazed window. A wall which is thicker or has insulation will perform much better. And this doesn’t count any insulation from plaster or cladding or whatever.

Concrete: 0.8 W/m^2K for 10cm solid dense concrete. https://ncma.org/resource/rvalues-ufactors-of-single-wythe-c...

Window: 2.1 W/m^2K for a coated especially insulating window. https://www.justrite.com.au/products-and-services/double-gla...

I wrote about conductivity here because that’s what your comment seemed to be about. Maybe I misunderstood your comment because it seemed to me that you were implying that windows transmit less heat than eg concrete walls (reading carefully, you don’t write that) and I thought it was a given that they transmit more heat. But my question isn’t about adding windows making a building require more heating but about adding windows making a building’s temperature harder to maintain because there are not a load of big (eg) concrete blocks in the wall releasing their heat into the air after you open the door and let a load of cold air in.

> But I don’t really know if modern buildings would want a large or small thermal mass.

This depends on climate.

When the outside temperature changes, the building will eventually get itself to the outside temperature (thermodynamics laws). How fast that change would happen exactly — depends on thermal resistance and thermal mass.

Thermal resistance acts as an amplifier (or rather diminisher) of that changing force: the higher the resistance, the lower is the force, and so more time for the change to take effect.

Thermal mass acts as a momentum against that changing force: the higher the mass, the more time for the change to take effect.

In some climates (e.g. south Europe) the outside temperature is only a problem on winter nights and on summer days. You are only fighting the outside weather for hours on end. And you can effectively make that fight with large thermal mass alone.

In other climates (e.g. north Europe) the low temperatures at winter can come for months, so you want mass, resistance, and inside heating.

In Russia triple-glazed windows have been as well pretty much standard for decades.

Somehow I think that might vary a bit. 20% don't have indoor plumbing, I'd be shocked if they had 3-glass windows in those homes. Of course, standard for new construction could be it ,as I guess there is also very little new construction in poorer areas.

People that don't have indoor plumbing certainly can't afford new windows, but their old (handmade) windows are usually double-glazed for warmth (and the part of the house that has single-glazed windows and uninsulated walls is abandoned for the winter.

Source: spent a few summers fetching water from a well and crapping into an outdoor toilet.

Someone just got a patent on transparent aerogel. It'll be interesting to see if they can make window layers out of it.

Holy frijoles!

https://news.mit.edu/2020/making-remarkable-material-even-be...

But aren’t average walls in Norway much more insulated? So the statement is still true?

What is the R-value of a Norwegian wall?

> What is the R-value of a Norwegian wall?

That varies greatly I think. There are a lot of old houses here; built to a very different standard than a modern house. Double glazed windows has been the norm for a long time though, through the invention of the easy to clean husmorvinduet or h-vinduet:

https://www.h-vinduet.com/

Husmor translates to housewife, vindu to window (housewife window). Easy to clean, since they can flip around, i.e. you can wash the outside from the inside. So for most older homes, I guess it's a mix.

For new buildings; what you say holds true I think.

Speaking for myself here, my house was built around 1850-1861 (no one really knows when it was made exactly). Timber construction covered with boards on both sides; but with minimal insulation (until we started renovating the house).

There are stricter rules for building new homes now, then what they had in the 1850's of course :-). A new house built now should follow the TEK17 standard made into law in 2017 (prior versions are the TEK10 standard from 2010, TEK07 from 2007, TEK97 from 1997 etc.). They regulate everything, from how much area you should have outside to how big a shed you can set up I think. Eco friendliness is an important category though; and these are the minimum requirements that came up with a google search (in Norwegian) for your question:

https://dibk.no/regelverk/byggteknisk-forskrift-tek17/14/14-...

Unfortunately in Norwegian as well, but they do state how much a wall/roof etc is allowed to leak; i.e. U value. As you can see (with Goole translate at least), walls should have better insulation than windows at minimum at least.

Norwegians build fairly typical Nordic homes. 198mm (8") studs with insulation between is pretty typical. Then another 48mm (2") insulated layer on the inside for services, and optionally a 50mm (2") insulation board on the outside before the cladding is applied. So 300mm (12") insulated thickness + whatever inner/outer cladding you use would be common, but up to 400mm will happen (300mm framing + 50 either side). Thicker than that is uncommon. U would be I think ~0.18 for the worst constructions but usually better. And yes, even the best windows have higher U than this. U=0.5 is fantastic for a window, and U=1.0 to 1.2 is common even in Nordic new construction (Standard 3-glass).

Quadruple glazing is insane, but it’s also ridiculously expensive.

Does Norway require insulation based on building profile or just walls must be X, windows must be Y?

By building profile I mean, higher requirements if you want massive windows; to account for their lower R rating than a wall.

Or higher requirements for a rectangular footprint vs a square footprint because the rectangle has a more surface area for the same volume.

(Does anywhere take this approach???)

> Does Norway require insulation based on building profile or just walls must be X, windows must be Y?

It's the walls must be X, windows must be Y:

https://dibk.no/regelverk/byggteknisk-forskrift-tek17/14/14-...

You're describing a prescriptive vs performance certification route. The former gives per-component minimums, the latter whole-assembly minimums. Most codes allow both, but most builders choose prescriptive because it requires less thought.

To put some numbers on "much worse" versus "not much worse":

The best window I can find from the major Danish manufacturer Velfac has a total U-value of 0.82 W/°K/m² [1]. It's a triple-glazed window with argon and coatings.

A typical insulated thin (100mm) wood-frame wall, i.e. the sort you'd use if you were building a summer house in Sweden has a U-value of 0.4 W/°K/m² [2], i.e. twice as good as the window above.

A typical rock- or glasswool insulated wood-frame wall for a modern year-round house has a U-value of 0.2 W or better, i.e. four times as good as the window above.

Wall that are so bad that they're roughly equivalent to the triple-glazed window above are something you'll mainly find in buildings from 50+ years ago, at least in Sweden. I expect Norway to be similar. [3]

'bjarneh' mentioned both triple- and quadruple-glazed windows. I've only seen quadruple used in noise-reduction applications, e.g. hotel next to a busy road. If you have a data sheet for one, it'd be interesting to see what the U-value is.

One of the posters above referred to 'R-value'. It's the reciprocal of the U-value. Wikipedia has good explanations of both, as well as typical values for windows and walls. [4,5]

References are mostly in Swedish, because the poster 'bjarneh' was talking about windows in Norway, so I wanted references for companies that actually sell things in Scandinavia.

[1] https://products-api.velfac.com/files/11644/VELFAC%20STANDAR...

[2] https://www.isover.se/hur-tjock-isolering-ska-man-ha-att-fa-....

[3] https://www.traguiden.se/konstruktion/konstruktiv-utformning...

[4] https://en.wikipedia.org/wiki/Thermal_transmittance

[5] https://en.wikipedia.org/wiki/R-value_(insulation)

> I've only seen quadruple used in noise-reduction applications, e.g. hotel next to a busy road.

The ones we got for our house was ordered with noise reduction, but I think that basically just meant that they did not have that little valve at the top of the windows (ventil in Norwegain perhaps also in Sweedish?).

My situation is somewhat special since I have a very old house (built around 1850) made from a timber frame construction (timmerkoja in Sweedish I guess?). So the walls were extremely poorly insulated, basically just some wool (or something similar, not 100% sure what it was) between the beams as they were put on top of each other during the build. Regular boards where added on both sides of the timber frame, but no additional insulation until we renovated the house.

The 50 year old punctured double glaze windows - that came with the house were not doing too much in terms of insulation either.

Any insulated wall will probably be better than windows, but at least here in Norway, there are a bunch of old poorly insulated houses, with double glazed windows as most everyone got these things installed when they came out:

https://www.h-vinduet.com/

Husmorvinduet (housewife windows) was popular since they were so simple to clean; and electricity was cheap until quite recently I guess. But any wall with actual insulation will probably beat windows for insulation; although newer windows are not as terrible as the once were.

> so I wanted references for companies that actually sell things in Scandinavia

I guess they are manufactured elsewhere; but I think the ones we ordered was delivered from Røros-vindu, but I could not find any info about actual R/U-value for the windows on their website. Just some info about what types of gas they contain and so on.