patrick.net

I don't have a heat pump, but one thing I have always done in South Florida when the weather gets frigid.
In bedrooms with a window unit, or a mini split, I put the AC on about 72 and crank it on high fan speed. The next morning, the room will be comfortable enough that I it's not too cold to get out of bed. Between 67 to 70, even if it is in the low 30's outside the bedroom door. I think it's due to the negative pressure that AC units like that creates, and air is an excellent insulator.
I haven't tried it with the central Air conditioner unit, as they always have a heat setting on them.

Some heating can come from sun, but that works best in the West. There is an example of a completely passively heated and cooled home but it takes ground-up design and $$$. Even then, without insolation in the winter 55 degrees is pretty cold.

HeadSet says

EBGuy says

Headset, what is up man. You are very skeptical these days.

Fellows, you were talking about residential heat pumps, which as Rickwicks said, are like reverse air conditioners. The common heat pump has the ability to move heat from a colder environment to a warmer one. Otherwise, it would not be a "pump," and it takes energy to do so. I have also toured homes that have "geothermal" for heating and cooling, where buried pipes circulating fluid take advantage of underground constant temperature to heat/cool that fluid before it goes through coils in a forced air blower. Nobody calls that geothermal system a "heat pump," as no heat is pumped. The only pump in a geothermal system is the pump that circulates the fluid. In fact, I had planned to have geothermal installed in the house I bought in 2014 but was denied by covenants.

There are Heatpumps that have water condenser loops (Ground Source Heat Pump.) The condenser loop of the compressor connects to the geothermal wells via a heat/energy exchanger. What it's actually doing in heat pump mode (heating) is grabbing the heat available out of the ground wells, as there is typically more heat energy available down there than in the surrounding ambient air above ground. In air conditioning mode (cooling) it is rejecting the heat absorbed from the evaporator into the ground wells, as there is a lower temperature for the heat to be absorbed by compared to the above ground ambient air, making it more efficient.