So, Are Heat Pumps a Product of the Devil???? - RV-Dreams Community Forum

Terry and Jo · RV-Dreams Family Member

So, Are Heat Pumps a Product of the Devil????

Luvglass · RV-Dreams Family Member

We have one and use it all the time when the outside temperature is above 45. A heat pump is nothing more or less than reverse air conditioning.

In hot weather when you turn on an air conditioner the air doesn't come out cold immediately, so on heat pump it doesn't come out immediately warm, but it will warm your rig and hold temperature. The choice comes down to using the campgrounds electricity to warm your rig, or your propane.

FWIW, we are very happy with one vented unit in our 36' rig.

traveljunkie · RV-Dreams Family Member

We have a 2009 Mobile Suites and have used the heat pump fairly consistently for the last few weeks. We are in Arizona, just outside Phoenix and the temps have been dropping into the 30's in the evenings. The heat pump has been working great, keeping the rig warm at night. Interestingly enough, the bathroom heats up the most.

-- Edited by traveljunkie on Monday 1st of February 2010 11:44:22 PM

bjoyce · RV-Dreams Family Member

We have two heat pumps and on 50AMP we use them exclusively since at 30 degrees it automatically switches to heat. When on 30AMP we use one down to the low 40s and switch to gas heat when below. A heat pump is much more efficient than an electric space heater and should be cheaper to run than propane. We have ducted air so that might make the difference on the draft.

DaveSam · RV-Dreams Family Member

Our old trailer did not have a heat pump but our new one does. I will never be without one again. It sures helps save on the propane.

Terry and Jo · RV-Dreams Family Member

Thanks, everyone. These are exactly the kind of answers that I have been looking for. However, in reading them, I now have follow-up questions related to the heat pumps.

I've only heard of these on other forums, but can you explain more about the "heat strip" in the heat pump?

Is it something that can be added after purchase?

How does it work to help in the lower temperatures?

Does it serve like a radiant in a heater and the heat pump blows air across it to get the heat out of it?

Sorry for all the questions, but when we order our unit in the future (not sure when - house not sold yet), I'd like to make sure I've done as much right as I can.

Thanks again. You all are always so helpful.

Terry

Luvglass · RV-Dreams Family Member

We have a Carrier air conditioner and it doesn't have a heat strip. Maybe other brands work differently. I've been told that the heat pump feature is nothing more than reverse air conditioning.

In regular cooling mode, the unit removes heat from the inside air returning the cooled air to the unit and expelling the hot air to the out side. I heating mode it does the opposite, removing heat from the outside air and exhausting the heated air inside.

That's the reason it doesn't work below about 43-45 degrees out side temperature. There's not enough heat that can be removed from the outside air below this temperature and the coils freeze up.

I'm sure there are others that know more about this than me and can chime in.

Roz · RV-Dreams Family Member

Terry,
Strip heat is just that - strips of conductive metal that give off heat when electric current is passed through them. Many portable heaters have always been strip heat. In the past, the strips were coils with high resistance that create heat.

This is not efficient as a heat pump that is, as Fred has pointed out, simply reversing the air conditioning process. As he also said, heat pumps, as air conditioning units, can only produce about a twenty degree differential in temperature.

In homes, as in RVs, the strip heat comes on to boost the capacity of the unit. Just uses a good bit more energy (electricity) as they are less efficient, but more powerful.

bjoyce · RV-Dreams Family Member

A heat strip makes the unit a space heater and puts out a small amount more heater than a space heater. I was told 5,600BTUs for a heat strip and 5,200 for a space heater since the air conditioner is run off a 20AMP breaker and a space heater off a 15AMP with a power cushion for the fans. A heat pump works as a reversing air conditioner and normally puts out about 11,000BTUs of heat for a 15,000BTU unit (what we have).
Our heat pump, a Dometic, works in regular mode to 38 degrees and from 30 to 38 degrees it periodically closes itself up and de-ices the coils. I can tell you it does keep the inside at 70 degrees when it is 30 out and we have experienced the automatic switching to furnace when below 30. In our RV the heat pumps do not run all the time even in the 30s.
Some people with heat strips have said that two will keep their RV warm when it is 25 outside, but they switch to furnace when colder to keep the basement heated. Others say that two heat strips do not keep their RV warm when it is in the 30s. I am sure this has everything to do with insulation.