question about heat pumps for travel trailers

[lewisma9]

Hello:
I'm looking at AC/Heat Pump combinations for travel trailers, and I haven't been able to find an informed comparison between the different brands, sizes etc. Has anyone done this kind of comparison or know where I could find one? I'm especially interested in comparing cost, capacity and COP/Coefficient of Performance data. I found an old comparison but at that time, the COP was not available for some brands ("not made public"). Has this changed in 2018?

Thanks for your help. I really value this forum.

Maryellen

[RV Doctor]

Maryellen.
In the North American RV market there are mainly two brands of RV AC units/heat pumps.
First is Dometic who have several models and then there is RVP. RVP is the former Coleman. They have two lines but only one of those has HP capability.
Heat pumps are used a lot on motor coaches and large fifth wheels.
Heat pumps are an AC system with the use of a reversing valve and system which create well, heat.
Problems with HP that a lot of folks don’t know. Mainly that you can only run them down to about 38F. They are really only to help on cool days.
Another problem is the reversing valves stick either on heat or AC. When this happens the unit is shot as it involves opening the refrigeration system which is time for a new unit.
Don’t know if you have looked into it but if you get a heat strip they can be added for the model of your choice. Heat strips can be used in all ambient temperatures without a problem. Also the heat elements used are bulletproof and last virtually forever.
If you search Dometic Heat Pump Specs and RVP Heat Pump Specs you should hopefully get what particulars you are needing.

[mszabo]

Here is a 15K unit quite large for the basic FG Trailers.
But it’s a start.

https://www.adventurerv.net/coleman-...t-p-29669.html

[Tom 72]

RV Doctor in post #2 above, knows his stuff. In mild climates, they are used for residential heat.

Heat pumps put out a high volume of luke warm air. But they work, and are a way to add heat without adding a furnace. You need AC power to run them. As the temp drops the heat strips kick on. Again, you need electricity, and more of it.

I could see their use for cold snaps in Southern climates. They aren't for boondockers.

Oh, residential heat pumps are probably reviewed by Consumer Reports. Search heat pump comparison. Most home furnace brands offer them, and Japanese names like Fujitsu, Sanyo, Mitsubishi, and Toshiba seem to specialize in them. Some here have mounted small residential units on tongue brackets. Searching threads here will find posts. I expect some roof top ACs incorporate them, as RV Doctor alluded to.

[lewisma9]

Originally Posted by RV Doctor

Maryellen.
In the North American RV market there are mainly two brands of RV AC units/heat pumps.
First is Dometic who have several models and then there is RVP. RVP is the former Coleman. They have two lines but only one of those has HP capability.
Heat pumps are used a lot on motor coaches and large fifth wheels.
Heat pumps are an AC system with the use of a reversing valve and system which create well, heat.
Problems with HP that a lot of folks don’t know. Mainly that you can only run them down to about 38F. They are really only to help on cool days.
Another problem is the reversing valves stick either on heat or AC. When this happens the unit is shot as it involves opening the refrigeration system which is time for a new unit.
Don’t know if you have looked into it but if you get a heat strip they can be added for the model of your choice. Heat strips can be used in all ambient temperatures without a problem. Also the heat elements used are bulletproof and last virtually forever.
If you search Dometic Heat Pump Specs and RVP Heat Pump Specs you should hopefully get what particulars you are needing.

Thank you very, very much! You have narrowed down my research considerably. Now I'll start researching "heat strips", whatever those are. Thx!

[lewisma9]

P.s. I live in Michigan, so 38 degrees isn't going to hack it for winter camping & fishing! ��

[Wayne Collins]

Warm air rises, and cool air sinks. A roof mounted "heater" needs a fan to move the warm air down. A floor or baseboard heater needs no fan. Natural convection circulates the warmth nicely; much more efficient! Get a small ceramic heater.

[Tom 72]

Wayne makes a good point. A small 8" cube shaped ceramic heater can do the job for I suppose $20-30. The efficiency of resistance heaters is identical, whether heat strips or tapes, or a small ceramic heater. The ceiling heater will require a bigger fan.

Any electric heat used for ice fishing will require a long extension cord. You'd need a big generator, and it would scare fish. Good luck.

[lewisma9]

Thank you Wayne & Tom, I really like your suggestion of a small ceramic heater. But please forgive my complete ignorance: Wouldn't I also need a furnace? Or can one use the heater for all my heating needs? I'm talking about really, really cold Michigan/Wisconsin/Minnesota winters.

Maryellen

[Tom 72]

Hello Maryellen, It depends. Thank you for asking.

Just kidding. Some owners of smaller, shorter, and tighter eggs get by with ceramic heaters down into the 20s. In some cases you could deploy two. They are about 1500 watts, have high/low settings, and basic thermostats. Others can tell you their experience with colder temps. Most eggs have a few cracks or leaks. Everything factors in.
Windows are major source of heat loss, as are any holes or cracks. Not to be too basic, but a 1/8th inch gap 9 feet long is 9 sq. inches, or equal to a 3" x 3" opening. Most cracks are shorter and narrower, but you get the idea. Jalousie window panes or poor window seals could add up. Insulation, shades, and window coverings like Reflectix bubble insulation with foil backing preserve heat. A cover for the vents of a ceiling AC unit might save a lot of heat loss. A vented exhaust fan might also lose a lot.
Humans, cooking, and gas appliances create humidity & condensation may result. A vent or crack may be the answer to condensation. It seems to me a small ceramic heater would reduce humidity, a benefit.

[Brian G.]

We own a 5,000 BTU portable heat pump called Climate Right. It wouldn't work for anyone other than folks like us with a very small RV. But we like it a lot because heat and a/c come from the same unit, and it sits outside our little rig so it's not in the way inside where we need the space. It keeps us very comfortable in moderate weather. But it will not cool us down a lot when it's above 95 degrees outside and we're parked in full sun. The heat has always been adequate although I doubt we've used it when the outside temperature was below 30 or so.

[thrifty bill]

IMHO, when you need a lot of heat, its tough to beat a propane RV furnace.

[ordjen]

That heat pumps have not been efficient at low temps has certainly been true. However, modern home heat pumps are now highly efficient and work down to zero temps. I have seen modifications of these "split system"units being used on RV's. The condensing units are commonly placed on the trailer yolk with hoses running to the cooling/heating unit inside.
Modern split system units are actually now more efficient than gas fired furnaces.

[RV Doctor]

David. Good point but just not a conventional system for a travel trailer.
I am in Puerto Vallarta Mexico as I write this. We have a Carrier split heat pump in the bedroom of where we are presently at. It is absolutely silent inside the bedroom!
Somehow these split systems never made it to the RV industry but would be awesome if they did!

[redbarron55]

My Chinese mini-split heat pump functions down to 17 *F and if anything at 9000.BTU may be too big.

[cpaharley2008]

I had a T@DA with a heat pump as well as a propane furnace. As mentioned, HP are only useful in shoulder seasons, once it gets cold you will need a furnace. There is a guy over on Escape forum that installed a split system in his Escape and is very happy.

[RV Doctor]

I think the min split system would be awesome for RVs but locating the compressor / condenser unit on the A frame doesn’t seem to be the way to go. You need your propane tanks and batteries up there for sure. So where else?
RV AC and HP units are loud! Our Dometic Penguin II is extremely loud!
The other question becomes where to mount the evaporator and fan assembly so as to get proper air dispersion.
Also, having the Condenser assembly on the front puts it right in the firing line for road spray and corrosion.

[Tom 72]

Like generators, people have found or fashioned brackets to mount them on the A frame. There's always the Dometic or Coleman roof mounts.

[lewisma9]

This is a REALLY helpful discussion. Now, I'm also wondering about the overall energy-efficiency of a dual heating system. For example, CPAharley2008, does it seem that your T@B dual system uses any more or less electricity/propane than a single heating system? On another forum, I read about a system where the HEAT PUMP kicked in during the temp drop when the FURNACE off-cycled, thus keeping the rig more consistently heated. Not sure exactly how that worked....

[Byron Kinnaman]

I haven't done the research but I believe that Heat Pumps require 120 VAC to operate. Many of us don't go to campgrounds with electricity hookups. Just something to keep in mind. If plan on only staying in RV Resorts (campgrounds with electricity) then many things will work. If boondocking is your thing, then it's time to think "off the grid".