Lowest temp to use heat pumps.

[Idleup]

LOL When I studied air conditioning and refrigeration many many Mango seasons ago - I remember studying there is still heat in any object at temperature as low as -459.67 degrees below zero. Anything colder than this contains no heat. and referred to absolute Zero

On my coaches - I've found that at temperatures much below 35 degrees, most heat pumps lose most of their efficiency. There is an exception when the air is very dry, it prevents icing on the condenser and allows the system to be more efficient at lower temperatures.

Regards- Mike

[KenNJ]

If you set your thermostat mode to automatic you should see your heat pump will work down to 35 degrees outside air temperature. If your oasis burner is turned on the oasis system heat exchanger fans inside will start working to maintain indoor temperature and will continue until the outside air temperature goes above 35 degrees. Recently ran my system in the automatic mode for an entire month and it worked perfectly.

[docj]

I'm surprised that no one has mentioned that in residential heat pump installations the usual practice is to make the switch-over from heat pump to backup not based on a particular outside temperature but on whether or not the heat pump can maintain the thermostat's set temperature. Most thermostats are designed to switch to backup when the room temp with heat pump lags by a preset number of degrees.

The advantage of this approach is that it automatically adjusts for the fact that a heat pump operating in a dry environment spends less time reversing to defrost, hence it is more effective than an equivalent heat pump in a humid environment. This is a more energy efficient approach than is arbitrarily changing to backup at a fixed temp.

[manderson2228]

I agree with the other folks in here. Our dealer told us that i needed to switch to the furnace at 40 anything over 40 heat pump was fine. Big part of the reason is the furnace pumps hot air down into the wet bay to keep your water lines from freezing.