4 ms·
except a heat pump which is far more efficient
by s0rce 8y ago
except a heat pump which is far more efficient
- SketchySeaBeast 8y agoUntil you get to below zero.
- lincolnq 8y agoThey now (as of 2018 I think) make Extra Low Temp heat pumps, which can work down to -15F. I think that makes heat pumps practical for a very wide variety of temperate climates.
- SketchySeaBeast 8y agoI see they do, but their BTU's are very low - I see the Fujitsu RLS3H, which goes down to -26C only outputs 12,000 BTU at that temperature. To heat a house at that temperature you'd need 5-10 (if not more) of those.
- golem14 8y agoOnly if you insist on the same duty cycle. Furnace might only run 4h/day, while heat pump could run all day (6* reduction)
- jrockway 8y agoI don't think that's quite true. The efficiency merely falls to 100%. (The laws of thermodynamics demand it.) Now, converting electricity to heat may not be as cheap as converting, say, natural gas to heat (thus making the heat pump un-economical when not pumping any heat)... but you do get heat out of it.
- SketchySeaBeast 8y agoThat's true. But heat pumps don't have the gross energy capability as a gas heater. To get the equivalent of an 85,000 BTU gas furnace you'd need to be pumping 25 kW through your heat pump at that point.
- titanomachy 8y agoI think one reason heat pumps have become more practical is that homes are now better insulated, making 85kBTUs of heating capacity excessive for all but the largest houses.
- SketchySeaBeast 8y agoWe've got an old, poorly insulated home which is why our requirement is so high. The average is 30 BTU / 1000 sq feet. That's 10 kW / 1,000.