Alabama Heat Pump Dual Fuel or Not

December 1, 2020 2:10 PM

I'm buying a house in Tuscaloosa, Alabama that needs a new HVAC outdoor package unit. I have a quote to replace the unit with a new gas furnace & AC for $4,875. I have a second quote for a dual fuel heat pump for $6,575. Both units are quoted by the same company and they would be installing Heil equipment. Questions: Will a heat pump save me money? Is it nuts to have a dual fuel heat pump in Alabama (we do have ~30 days a year below 35F)?
posted by gregr to Home & Garden (10 answers total)

The real question is an electric heat pump more efficient than a gas furnace for all of the days that are between 35-60F, and is that efficiency worth the extra cost from just having a regular gas furnace. Answer is probably Yes. Play with some numbers here.

Nuts to have a dual fuel heat pump? Not at all, if you have below-freezing conditions and you want heat.
posted by Diddly at 2:38 PM on December 1, 2020

Contemporary heat pumps are quite good in temps well below freezing. I’m up in Indiana with a new heatpump and do just fine in our winters, which are probably a whole lot colder, for longer stretches, than Alabama winters. I can’t imagine needing a dual-fuel heatpump down there, unless they’re pushing the cheapest, least efficient model on you.
posted by Thorzdad at 4:54 PM on December 1, 2020 [1 favorite]

Here in Atlanta I have a regular heat pump, and when it gets close to or below freezing the Auxiliary Heat function comes on. According to the HVAC company that installed and maintain it, those are "heat strips" that heat up the forced air when it's too cold for the heat pump to do it on its own.

I'm guessing "dual fuel" means gas and electric? I'm not sure why you'd need that, unless for some reason that means that if your electricity was out the heat pump would still work?

Is there a way to ask your neighbors what they have? I'm not clear on what the dual fuel system that's almost $2000 more gives you that you won't get with the regular system.
posted by ralan at 6:43 PM on December 1, 2020

Live in AL. The heatpump will likely operate cheaper. Dual fuel just means the heat is gas and the cooling is electric. Dual fuel heat pumps are very common here where natural gas is available at the house. My heat pump is fully electric and works fine in the winter. The aux strips rarely come on.

I assume the $6500 is to replace the outdoor and indoor unit? If that's just for the outside unit, I'd get quotes from other companies. Modern heatpumps are typically matched, designed to operate with a matching indoor unit. You don't mention the tonnage or seer so no way to know if that's a decent price.

Just for reference, a few years ago we got a new 2-stage heatpump and matching variable speed indoor unit, 2.5 ton, 16 SEER for ~$7k.
posted by LoveHam at 4:37 AM on December 2, 2020

Response by poster: @Diddly thank you for that calculator. It's better than other ones I had seen. It suggests i'll save ~42% per month in the cold parts of the year with a heat pump.

@Thorzdad & @ralan & @LoveHam Auxiliary heating -- I'm nervous that if I get an extended cold snap the electrical auxiliary heating will cost a whole lot.

@ralan The ~$5k quote is for a non-heatpump system that would have a standard AC unit plus a gas furnace, so the additional ~$2k is mostly for the heatpump part.

@LoveHam Thank for the datapoint about Alabama-- I haven't been able to find much actual on the ground data from heatpump vs non-heatpump users. This is one of those all in one units where the whole thing sits outside, so no indoor parts.
posted by gregr at 8:07 AM on December 2, 2020

I once lived in an apartment in northern Arkansas with a 1986 heat pump. In the years I lived there it needed to run the auxiliary electric heat one or two nights a year. Never was the electric bill surprisingly expensive since it had to get below 15F or so before it needed the electric heat. The gas bill for our furnace in slightly colder Tulsa cost a lot more than the electric ever did.

In Alabama, you really shouldn't need gas auxiliary heat in a heat pump unless your electric rates are stupid high, in which case a heat pump might not be the best option financially anyway. But it almost certainly is better in the long run to use a heat pump unless you live in an unusual microclimate where it gets much colder than the areas around it.
posted by wierdo at 9:10 AM on December 2, 2020 [1 favorite]

we do have ~30 days a year below 35F

You may have days were is gets below 35F but I doubt you have many days were is stays below 35F all day. More likely for just a few hours at night.

You don't list the option of heat pump with all electric, no gas. Since you are in a relatively mild climate, the gas option might not save you much. So it would be a question of whether an all electric heat pump price is cheaper than an dual fuel heat pump. If the price difference is small, you may as well get the dual fuel. If the price difference is large, you may be better off with all electric.
posted by JackFlash at 10:36 AM on December 2, 2020

@Thorzdad & @ralan & @LoveHam Auxiliary heating -- I'm nervous that if I get an extended cold snap the electrical auxiliary heating will cost a whole lot.

My experience with my heatpump has been that it has to get pretty hellishly cold and windy for the aux heating to kick in for. Like, down into the teens. Seriously. And, when the aux does kick in, it's usually just for a minute or two. The few times I've seen the aux stay on, it's been close to single digits and windy, and we rarely get conditions like that for extended periods.

I'm constantly impressed by the heat the thing churns out in seriously cold weather.
posted by Thorzdad at 10:45 AM on December 2, 2020 [1 favorite]

I would also recommend getting quotes from at least three different contractors. Pick their brains on their recommendations for different options. They know your climate best and install hundreds of systems a year and what customers like best.
posted by JackFlash at 10:48 AM on December 2, 2020

If money is not the only consideration, and depending on how your local electricity is generated and the local climate, it's worth bearing in mind that a heat pump is usually better for the environment than a gas furnace. The average US home is responsible for about 18 tons of CO2/year. Of that, about 1 ton is the gas furnance (see e.g.). Switching to a heat pump will reduce that 1 ton by a lot. It will reduce it to essentially zero if your local electricity is not fossil fuel-based, or you can pay extra for "green electricity". So it could reduce your carbon footprint by a few per cent.

YMMV and this is not the only relevant factor. But I think it should be a factor (alongside upfront and ongoing costs, access to gas/electricity, etc.)

p.s. one other tip: you may find that rebates are available for the heat pump option that are not available for the furnace. Check with your local electricity supplier, county, state, etc.
posted by caek at 10:49 AM on December 2, 2020 [1 favorite]