—”Electric heating is much less efficient than gas. “
Not true, but the answer is a moving target and somewhat technical.
Here in northern Illinois the price of delivered gas/electricity constantly changes.
For electric resistance heat the efficiency does not change, but the efficiency of a heat pump changes with the outside temperature called the coefficient of performance (COP).
For the heat pump my wife and I installed last year @40F the COP is 4:1 (four times ERH) at MINUS 15F, it drops to 1:1 (same as resistance heat)... around -20F electric resistance is MORE efficient than my heat pump.
Around 20F we switch to a 94% efficient GAS boiler.
depends on the price of energy, last we used the HP most of the winter.
Thanks for the tutorial. I have to read up on heat pumps.
In our part of the country heat pumps make a lot of sense since we get few cold snaps below the teens. In the last two instances, when temps dropped to single digits and slightly below the heat pump efficiency was amazingly close to nameplate specifications. In '21 we shut off the old 90s vintage central system heat pump because it had gone negative. Not producing air as warm as the conditioned space. Amazingly, an 18 kbtu and 9 kbtu mini-split kept the whole house at 68 or above. They are located at the ends of opposite wings of the house. To be sure, distal places were cool but not cold and nothing froze.
The LG Red mini-splits are pretty efficient all the way down to about 10 degrees. The Mr. Cool unit in the shop sips juice keeping 900 sf at 62 in the winter and about 80 in the summer. I am not happy that 62 is the lowest setting. We have added the last 1000 sf to the house and it is a three zone LG Red mini-split system. Anxious to see how it works. I'm finishing up the install this week.
As I write it is around 40 and the only unit that is on is the little 9 kbtu unit blowing air down the hall and into the rest of the house. We just foamed the roof decking in the old portion of the house and one addition, a total of about 1800 sf with the total being about 2400 sf. I'm not declaring success yet and we still need to freshen the blown fiberglass but something has changed. I am anxious to have conclusive data.
I wanted earth source but the mini-splits come close most of the time. The earth source units last forever since the compressors just never work very hard. A neighbor had one of the originals installed in the early 70s and three owners later, believe it or not, it still works.
Ducting is what puts the earth source heat pump efficiency down in the mini-split range for normal conditions. If you put the ducting in the conditioned space I don't think you could beat it.
The wood stove back-up heat does not have an outside air source. That needs to be changed. It is so inefficient since it pulls air into the house to vent I only run it for ambience or just when necessary.
With the fools in DC getting their way we are all going to have to learn a lot about efficiency to manage to keep warm or cool for as long as we can.