GaryB said:
Although I know what a household heat pump is/does, what are the advantages and disadvantages to a heat pump in a 5th wheel, as compared to the standard roof A/C and furnace?
Interesting thread, Gary. I wasn't aware that RVs came with heat pumps. I had one once in an apartment complex. At the time I had never heard of one -- so when the repair guy came to fix mine that didn't work when I moved in -- I asked him "how" it worked. He responded, "I don't know, I just fix them". Anyway, after finding out their usefulness, it made sense for an apartment complex. The builder did not have to spend as much money installing both an air conditioner "and" a furnace in each unit. They did install a cheapo electric heaters for far less than the cost of a furnace to supplement the
INefficient side of a heat pump.
From what I read here, rigs with heat pumps also have fully efficient propane furnaces -- so the idea seems to be to give the RVer more choices on how to save on energy costs -- as RVRoamer and John pointed out. Also, John's example of turning a window air conditioner around is a good analogy of "the results" of how it works. And that also demonstrates the only potential drawback.
My A/C is the biggest energy hog on board my RV.? It's the one item I am the most careful of if I am paying for it's running cost. For example, I only have a 20amp circuit where i am now parked so cannot run any other electric items requiring big watts. When dry camping, the genset "must" be running to do Air. And a Heat Pump, either way it is running, is an Air Conditioner -- and requires the same energy to operate. Turned one way it is cooling the inside of the rig -- while turned the other way, it is attempting to air condition "the world" outside.
Air conditioning the world involves each of those little molecules (of whatever type of liquid is used in the Pump) sucking energy in the form of heat from the environment as it becomes a vapor to later release inside the rig during condensation. The? colder it is outside the less energy for the little molecules to suck up. And that is the downside of a heat pump. The colder it is outside (and the corresponding need for heat inside), the less efficient the unit becomes. The hotter it is outside, the more efficient the heat production is inside.?
But going back to John's original response, we all want to use park power when available, and our own propane and genset when it is not. If an RV has a propane furnace as well as a heat pump, I would agree with RV Roamer in that if the cost is not that much more, and you understand exactly how it works, I would see it as an asset to give more alternatives in energy cost savings. That would be considering the incremental cost over just Air and a furnace. How much incremental cost would one be looking at that they would have to amortize in energy cost savings vs. just an air conditioner and furnace? "Rarely" do I need more to heat my Class A than one of those little "cube" type CW heaters.