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.

[wed]

Just set to heat the heat pump will work until it’s gets to cold then the propane heat will kick on.

[Derby6]

Originally Posted by wed

Just set to heat the heat pump will work until it’s gets to cold then the propane heat will kick on.

See my post 16: that is counterproductive when it gets too cold because heat pump will continue to operate blowing cold while furnace blows heat.

[scottz]

Originally Posted by TripleP

I have a 2021 Montana 3761 FL. Am I to understand that my rear AC that is in my bedroom is the one with the heat pump? I was under the assumption it was the middle AC in the kitchen. Unfortunately my rig is in storage and I can't check at this time. Thanks

I have no experience with the new in-command. My larger AC in the main living area is the heat pump

On my units with thermostats, the modes reflected on the thermostat are set by the AC unit. Whichever unit is the heat pump, will display that option. The other unit (that does not have a heat pump) will not display the option. This was true with the Dometic thermostats and with my new Micro Air thermostats. The Micro Air connected my heat pump unit has a option that looks like heat pump/furnace. Never tried it, but it might switch to furnace when it is too cold for the heat pump; or maybe it runs both at the same time.

The heat pump in my house also feels "cool". That is the nature of heat pumps; not like a furnace with a burner that puts out hot air.

[Clark Jacobson]

Thanks! That's good to know