Heat Pump question

[Clark Jacobson]

We used our camper this past December with one night at 16 deg and another at 11 deg using the electric furnace and fireplace. The termperature held fine.

[dieselguy]

If I understand you right, at 11F - 16F outside air temp, using the heat pump and an electric fireplace the temperature "held fine". If I might ask, what was that indoor temp reading that held fine?

[RMcNeal]

I'm not Clark, but I've kept my rig around 60 degrees inside and in the high 40's to low 50's in the underbelly and basement using only the fireplace, heat pump and a supplemental electric space heater. The heat pump mostly was circulating the warm air produced by the fireplace and space heater.
The outdoor temps were in the single digits. Once temps got below zero, all bets are off. Furnace only then as I was worried about pipes freezing.

[Cat320]

Originally Posted by dieselguy

.....at 11F - 16F outside air temp, using the heat pump and an electric fireplace the temperature "held fine"...

Maybe I'm missing something here, but heat pumps do not work below about 40F.

[RMcNeal]

Originally Posted by Cat320

Maybe I'm missing something here, but heat pumps do not work below about 40F.

You're not missing anything. They are not very good below about 40F, but they certainly will run.
If you can keep some warm air circulating through it, it essentially will "work", but mostly just circulate that warm air through the racetrack ducts. Using the fireplace and supplemental electric heat provides a source of warm air to keep the coils from freezing up well below the 40F mark.

[mhs4771]

The returns and outlet on the ACs are two different animals with no connection between the two unless you already have an AC issue. So it can't recycle the inside warm air. All they'll do is blow cold air.

[DutchmenSport]

Originally Posted by mhs4771

The returns and outlet on the ACs are two different animals with no connection between the two unless you already have an AC issue. So it can't recycle the inside warm air. All they'll do is blow cold air.

I "think" what they are describing is the "warm" are inside the coach produced by the "electric" heating devices (fireplace and electric space heaters). The "return" vent on the Air Conditioner/ Heat pump, pulls that warm air and simply pumps it through the air ducts.

Putting the AC in "fan" mode only will do the same thing. (maybe even do it better.)

I will admit, I tried doing this. But when temps get to about 20 degrees outside, there simply is nothing but COLD in those ceiling air ducts. The "warmth" being cold from the inside of the coach area is NOT enough to warm the ducts up. Nothing but cold pumps out of the ceiling. It's actually counter productive. Now, running the gas furnace and placing those same space heaters around in different locations.... THAT works! But using that heat pump, I agree with you....

[mlh]

And when you recirculate air through the ducts you are actually lowering the inside temperature because heat is lost through the ducts.
Lynwood

[Clark Jacobson]

We had the cabin temp at 68 deg. I don't know what the temp was under the floor but the water ran. Everything seemed fine. Now I say it seemed fine, My wife might argue.