Maybe the gas is cheap, but the monthly and up-front connection costs mess with the economics.

And that cost will only go up as people cut the gas cord.

Depends on how your utility bills out it’s infrastructure: some charge minimal monthly connection fees, others a lot.

I honestly wouldn’t want to own a residential-focussed gas distribution company unless someone revolutionizes stirling engines or micro cogen systems and people start cutting their electric cord.

I live in a pretty standard suburban subdivision in the US. All the houses are 25 years old. I have about 60 coworkers in very similar situations. I think everyone of us has natural gas that was installed when the original company built all the homes in the subdivision over the course of a year. Stuff gets a lot cheaper when everything is put into the ground at the same time. My monthly gas connection fee is $10 so that in the summer my bill is around $19 which is $9 for the water heater and $10 for the connection fee.

In most places in the US, in normal working conditions, Heat Pumps are 30%+ cheaper than a gas furnace to run.

However, in some really cold places like Chicago, Minneapolis, etc - the days where current heat pumps are inefficient might be enough to make it cheaper to always run gas.

OP is proposing to have both systems and only run the gas furnace on extreme days - which would lead to a ~30% reduction in running costs.

I suspect the CapEx of having two heaters wouldn't make sense, though.

It'd be better to just have a hear pump that can run efficiently at colder temps.

I think it’s the opex of 2 grid connections that messes with the numbers.

Depends on how your utility charges, but I feel like many/most sell you the gas roughly “at cost” and then some fixed monthly delivery/connection charge that covers their regulated rate of return on their network equity.

Oil or propane supplemental heat might be cheaper than Natgas supplemental heat. My money is on wood pellet stoves for supp heat for those that don’t require full automation. Or maybe even dirty coal…

Also, the capex of gas delivery. Not needing infra to deliver gas to each and every house would likely be a pretty big win.

For new construction sure - for existing it’s already there and apparently needs little maintenance.

You generally have an air conditioner though as well as a furnace and you can get those that can also work as a heat pump. Mine supposedly works as both but they only set it up for cooling and my gas furnace does all the heating :(

The thing with heat pumps is that they can be as much as 300% efficient (effectively) or more. This is because they can get "free" heat from the environment.

So even if per unit of energy gas is way cheaper, heat pumps can still come out ahead.

Modern heat pumps can be up to 500% efficient (using 1kWh of energy gives 5 kWh of heat) at optimal temperature.

Yes, I went with "300 or more" because that's a more typical number for a run-of-the-mill unit.

And even the low-temperature-capable heat pumps reduce toward 100% at the low temperature end, IIRC.

Yep, here's a spec sheet for a unit I'm looking at as a drop-in ducted replacement for my existing system -- it has all of the models listed, but I'm looking at the 4-ton unit (12k btu per ton, so 4-ton = 48k BTU, hence the MDU18048): https://mrcool.com/wp-content/dox_repo/mc-uni-perf-ss-en-01....

It takes 7kw at 17ºF to provide 48k BTU. There are 0.293W/hr per BTU so 7,000W = 25k BTU "in" and 48k BTU "out" or a COP of 1.9. At -15ºF, it's using 5.9KW but can only produce 28,500. So a COP of ~1.4. Still better than electric resistive heating but not by much. At 40ºF, the COP is more like 3.3 which is in line with the very efficient numbers.

Fortunately my 99% design temp is ~8ºF and my area only sees 20hrs below zero per year, so this will work just fine for me.

This is true when it’s warm enough outside that you don’t need the heat pump anyway. When the temperature becomes cold, it’s a different story.

Heat pumps might make sense when you have a well-insulated house, like the kinds in Northern Europe, to trap heat and reduce the power required to heat the room. American houses in most places are far too drafty.

> Heat pumps might make sense when you have a well-insulated house, like the kinds in Northern Europe, to trap heat and reduce the power required to heat the room. American houses in most places are far too drafty.

If you need significant heating or cooling in a home, the first thing you need is to deal with is insulation, otherwise nothing you do is going to work well.

That’s true, but unless you are doing some kind of industrial work (including running very hot computers), you shouldn’t need significant heating or cooling in most of America.

The idea that indoors needs to be between 72° (F) and 75° at all times is unsustainable.

The other problem is that if you do decide to insulate the house, then you may end up needing to use A/C because the house can no longer be wind-cooled to an acceptable temperature, and you will need to update the heating system as traditional methods of heating (fireplace, stove, simple furnaces) depend on external air circulation.

> That’s true, but unless you are doing some kind of industrial work (including running very hot computers), you shouldn’t need significant heating or cooling in most of America.

> The idea that indoors needs to be between 72° (F) and 75° at all times is unsustainable.

The WHO recommends a general minimum household temperature of 64°F for all populations for health reasons, with a higher minimum for sensitive groups including children and the elderly; maximums are more regionally variant because acclimitization (which takes years) plays more of a factor in high-heat health risks, but even in extreme regions seems to top out at about 90°F for the general population.

Lots of the US spends lots of time significantly out of at least one end of that range (and, especially given that the top gets lower in colder regions, lots of the US spends lots of time significantly out on both ends of the scale.)

> The other problem is that if you do decide to insulate the house, then you may end up needing to use A/C because the house can no longer be wind-cooled to an acceptable temperature

If you have a house that is insulated well and also lacks doors and windows that can be opened, sure.

But... that presents other problems, too.

I’m talking about significant cooling and heating, which is what you mentioned. Set your thermostats to 66° F heating and 88° F cooling and compare your electricity gas usage to 72° F/75°F for the year.

Unless gas is subsidised I don't really understand how gas can be cheaper. A modern heat pump can give 3-5 kWh of heat using 1 kWh of electricity. And a modern gas generator is roughly 50% effecient at creating electricity (according to the Internet). So by using electric and a heat pump you should be able to get 1.5-2.5 times more heat from the same gas by making electricity of it first compared to burning it directly.

At least in the US, electricity rates and natural gas prices are highly regulated for retail customers. Thus the wholesale price of gas does not generally correlate to the retail price of electricity. In places like California electricity prices are very high due to renewable generation requirements. You would definitely want to have your own solar installation before converting over to all electricity in that state.

We’re being forced to. After 2030 no more gas water heaters or furnaces can be sold. The cost of heating your house and water here is going to probably triple or more, and will fail every time there’s a blackout.

You used to be able to buy water heaters that would last forever. My house had one from the 1950's with a copper tank. Still going strong. Just don't be convinced b y the repair man to get a new one when you have to replace the thermocouple every 8 years or so. The furnace is from the late 1980's, still fine.

I'm not sure if such well made devices are still available for purchase however.

Modern residential gas furnace is 90% or more efficient.

Makes sense (I would have guessed closer to 99% actually). But 99% is still less than both 150% and 250%:-P

You seem to assume that energy cost is the same no matter how it's delivered. Here in California, electricity is much more expensive than natural gas for the same amount of potential energy.

Yeah delivery cost might be a factor, maybe it costs more to deliver 1 kWh of electricity through a wire than (the equivalent of) 1 kWh of gas with a truck (that's what you use right?). Gas, if its stored in a big tank under your house, also had the advantage of beeing "locally cached", so you don't have to dimension the system for the max load in the same way.

Many urbanized areas in the US have natural gas distribution pipelines.

Rural areas rely on propane delivery, which is roughly 2x the cost of the piped natural gas (per unit of energy).

What is the efficiency of the power generation system? The whole system costs matter not just the individual HVAC unit

> A modern heat pump can give 3-5 kWh of heat using 1 kWh of electricity.

At lower temperatures the modern heat pumps cannot attain this COP, which is why they are working on heat pumps that work at lower temperatures.

I imagine there are more costs in running a power plant than the cost of fuel - hydro, solar and wind power is not free despite not using any fuel.

Interesting thing here is that natural gas is about 1/3 the cost of electricity per energy unit, so when the COP is above 3, it's cheaper to heat home using heat pump.

The reason why natural gas is about 1/3 of the cost of electriciy is because most natural gas power plants run at thermal efficiency of about 30%.

Combined cycle natural gas plants have an efficiency of about 60% (lower heating value). Even simple cycle NG plants are about 40% efficient (again LHV).