Every HVAC company I've talked to in Houston has advised me against heat pumps. Mainly, natural gas is so cheap in Texas that the cost benefit analysis doesn't work out.
Where I live electricity has been getting cheaper faster than natural gas, so at some point it makes more sense to do a heat pump.
Plus if natural gas is cheap it can also be used to generate electricity without having to run and maintain natural gas lines to every house as well as electrical lines.
Therefore the choice is between a gas furnace at 90%, or gas to electricity to a heat pump at 150%, if we care about the efficiency of gas usage between the two options.
But when comparing price per kWh of delivered gas vs electricity, ignore the 50% gas-to-electricity efficiency, because that's irrelevant. It's just the 90% vs 300%.
Therefore a gas furnace is cheaper if the delivered price per kWh of gas happens to be no more than 30% that of electricity in your area. Of course the rate for gas will more likely be in therms than kWh, but that's a simple conversion (1 therm = 29.3 kWh).
I suppose that's the case in Texas?
> if natural gas is cheap it can also be used to generate electricity without having to run and maintain natural gas lines to every house
It's recently become so high, I wonder if it's more economical to run hybrid cars on gas instead of charging them.
A typical Texas house has one unit that is both AC and furnace.
Most houses built in the last 50 years have central AC. Given that you'll have ducts, the simplest and easiest way to heat the house is to use them. In other words, it's forced air heating. It's really not a great form of heating, but it's adequate for relatively short, mild winters.
So if you replace your one AC/furnace unit with a heat pump unit, you probably won't have a gas furnace anymore to do the comparison. (Apparently, there is such a thing as a "dual fuel heat pump", though, which can heat with gas or heat pump. I'm not sure how much those cost.)
Another factor is that AC is the bigger concern for energy usage because AC is used much more of the year. So when replacing your system, whatever money you can spend on an upgrade, you're probably better off putting it toward improving AC efficiency rather than heat efficiency. Or toward something that will help with both, like insulation.
Given that an AC is just heat pump, but with the hot bit outside, and the only thing needed to swap the hot and cold bits is a reversing valve. A high efficiency heat pump is also a high efficiency AC (that’s a very tautological statement).
So investing in improved heat pump for heating, naturally means investing in an improved heat pump for cooling.
However, our main motivation was to stop destroying the planet. Also within ~25 years, the government will require every building to be disconnected from gas (to achieve CO2 reduction goals). And from 2026 onwards, gas heating can still be installed, but it it'll be required to install a hybrid heat pump as well (a lower-capacity heat pump, where the gas furnace is a backup).
This holds true even if your current electricity mix involves coal or other things worse than natural gas. Those plants will have to be shut down within the lifetime of your appliance or neither thing matters very much.
[0]: https://afdc.energy.gov/fuels/natural_gas_renewable.html
There are lots of variables, but return on investment in solar is around 14% annually for me. It'll vary from place to place, so you need to do your own math.
It is interesting how the numbers work out in different places. Where I'm at it doesn't make sense at all. So much of my bill is just to have a meter and the per kilowatt rate is crazy low. Because of the high fee just to be hooked up the only way solar wins here is to get off grid - but winter kills that idea.
But in Texas, a heat pump wound probably be great. But yeah, natural gas is cheap.
The only people willing to install heatpumps are from an hour away and who spend their time building luxury homes. It's crazy to me that the rest of these guys aren't out there working with those Federal IRA funds and installing heat pumps left and right. We're climate zone 4 with a design temp of 6ºF, just about every modern HP will spend 99.9% of its time working at full BTU here.
I have my EPA cert, and I'd still probably go that route. The recovery pumps are expensive ($500+) and you need a recovery tank ($100), and then you still need to find somewhere that will take it from you. For a single job, it might be better to pay a HVAC company/moonlighting tech to do that part and do all the manual labor yourself.
With the way supply chains are right now, getting a less common unit means if you have a problem, and you will because half the components are imported now, you're going to be sweating it out while you wait 3-6 months for a part, and that's if you can find a tech to come out and diagnose it properly.
If I lived in the deep south, I'd get whatever the standard equipment is and spend the difference on extra solar panels.
(Also, which is more likely in ten years: that natural gas will be cheaper than today, or that electricity will be? I think with the huge new investments in renewables, the latter is more likely.)
(I know everyone is expecting the entire grid to be 100% renewable on electric but it's going to take decades and by that time people can switch to new heat pumps. In the meantime we can save energy that way.)