Air to Air Heat Pump in cold temperatures

[hvacker]

Inverter heat pumps retain high efficiency and high output to very low temperatures.
Though the government is not my favorite source of information, here's an article about "cold climate heat pumps."
https://www.energy.gov/eere/building...ay-warm-winter

I have my dual fuel system (or "duel" fuel if you're an internet speller) set to lock out the furnace above 15°F. House temperature maintains 72°F. I have read of some with dual fuel who haven't used the furnace in two years.

Ya I think dual is two and duel is a sword fight. Then there's duet and dude & duck which is either a bird or what you better do in a duel.
I've got too much time on my hands.

[Kroaler]

Inverter heat pumps retain high efficiency and high output to very low temperatures.
Though the government is not my favorite source of information, here's an article about "cold climate heat pumps."
https://www.energy.gov/eere/building...ay-warm-winter

I have my dual fuel system (or "duel" fuel if you're an internet speller) set to lock out the furnace above 15°F. House temperature maintains 72°F. I have read of some with dual fuel who haven't used the furnace in two years.

Going to be hard to see an ROI on the extra cost of the furnace if they havent used it in 2 years.

[kdean1]

Going to be hard to see an ROI on the extra cost of the furnace if they havent used it in 2 years.

The lesson is that modern heat pumps need minimal backup heat so consider going all electric. But I don’t recommend it with a single stage heat pump.

[Inspector314]

I dumped the single stage HP with oil backup and went with a 2 stage HP all electric and have not looked back. I have no lockout and the system will start kicking on banks of 5kW electric backup around 19 degrees. I think the only time it ever kicked on all three banks was when it was sub zero and my house is not all that well insulated (circa 1989 construction).

The only time I force emergency heat is during freezing rain or heavy snow.