7 ms·
Scroll compressors have come down in cost a bunch in the last few years. There's really very few reasons not to get a heat pump, now, for new construction.
by FuriouslyAdrift 4y ago
Scroll compressors have come down in cost a bunch in the last few years. There's really very few reasons not to get a heat pump, now, for new construction.
- bityard 4y agoEven in areas where natural gas is much cheaper than electricity?
- icedistilled 4y agoyes. Because Global warming/climate change is real and installing new furnaces bakes in decades of additional natural gas usage. Also, that natural gas price may change.
- bombcar 4y agoIf you want to spend the money you can get systems that have heat pump, gas furnace/boiler, and electric. Often used for larger installations that can take advantage of differing prices - and can work best with water heat.
- dgacmu 4y agoA heat pump is likely to have an average efficiency of near 300% - call it 250 if you want to hedge. A high efficiency condensing gas furnace gets about 95%. So on a per-watt-hour basis (equiv., BTUs), your gas must cost less than roughly 1/3 what your electric costs. There are additional savings if your gas furnace is the only gas appliance in your house and you can remove gas service entirely, saving the monthly customer fee.
- pandaman 4y agoAnd to get to 250% COP in heating on average you'd expect to have, at least, 8.5 HSPF2 rating on your heat pump (it's still just the heating performance w/o de-frosting cycles as far as I understand so the real world COP of a 8.5 HSPF2 will be lower than 2.5)
- crgwbr 4y agoUnfortunately that is the case in some places. Last year I did the math to see if a ground source heat pump would be feasible (Hudson valley, NY), but even accounting for 400% efficiency vs 95% for gas, gas was still ~30% cheaper per month than electric. And that’s ignoring the extra $50k in equipment cost for the heat pump.
- chii 4y ago> gas was still ~30% cheaper per month than electric this sucks, because gas _should not_ be that much cheaper than electricity, but for subsidies or other market altering shenanigans.
- tshaddox 4y agoNamely externalities. Natural gas is almost certainly more expensive for home heating than electricity, it’s just that a portion of that expense is paid by a large number of third parties.
- rsj_hn 4y agoSeeing as how natural gas is a required input for making synthetic fertilizer, without which billions would starve, it's hard to think of a product with more positive externalities than natural gas. Every time you go to the supermarket, you should be thankful that natural gas allows synthetic fertilizers to feed the world. It's easy to think of negative externalities and ignore positive externalities (or vice versa), but accurately summing these up is very difficult.
- bityard 4y agoI don't have any hard data at hand, but I can say that running my AC (which is just a one-way heat pump) for a few days out of the month in the summer makes my combined gas+electric bill about the same as in the middle of winter when my gas furnace is running all the time.
- FriedPickles 4y agoId love to see a combined heat and power system that burns natural gas to drive a heat pump compressor, and recovers the combustion heat. I wonder what multiplier it would get on a therm.
- nanomonkey 4y agoI've been contemplating the same thing. Something like the WhisperGen stirling engine hot water heater should be available to everyone. Hell even a water cooled honda generator that runs off natural gas, and pumps the radiator fluid into your home for heating purposes would be nice. It seems weird that we aren't producing electricity when ever you burn natural gas for heating.
- lazide 4y agoThe issue is maintenance and capital expense due to complexity. Gas furnaces are dead simple, and still break and require maintenance. Heat pumps, more so. Generators? By far the most. Combining the three sounds like a huge headache for marginal efficiency gains.
- nanomonkey 4y agoThis is why I started off referencing external combustion engines like Stirling engines. These tend to have very low maintenance needs as the combustion occurs outside of the pistons, so there is no fouling of the moving parts. One could use self lubricating materials like graphite rods as your piston heads and have quite high reliable components. The stirling engines that NASA utilizes are considered maintenance free. As far as efficiency gains, we're talking 25-40% of the energy being produced as electricity and the majority of the rest being turned into hot water for residential use, either by one household or a whole city block. This doesn't sound like a terribly marginal gain. Specially if the energy production is done during the hours when traditional solar installations are not producing which are generally when folks are running their heating.
- maxerickson 4y agoGenerators with heat recovery exist, search on micro CHP.
- nightski 4y agoThe main reason in my area is that a.) these fancy new efficient ones aren't available easily and b.) no contractors in the area to install/service them. I just got a new gas furnace and really wanted to add a heat pump to the mix but after several quotes all of them either said no or strongly avoided the question. I couldn't get a straight answer.