When to use between Heatpump and Furnance

[55AS]

Originally Posted by cazual6

Why is that exactly?

Look at my other threads for details. This system uses very little current (6 amps or so) and is very quiet.

[55AS]

Originally Posted by Foiled Again

Dear BambiTex - looked at your profile... Unless you've replaced the units, wouldn't you have heat strips rather than a heat pump?

My first - a 2005 - had heat strips (electric heating elements same as a space heater) rather than a heat pump (reversible a/c which pumps heat OUT in summer and IN in winter.) Even as recently as 10 years ago heat pumps were rare on trailers - but the technology has improved greatly since then.

Paula

I installed a residential "inverter style" split system air conditioner with the compressor mounted on the tongue. It is also a heat pump (reversible A/C) and runs very quietly and uses about 6 amps. Very pleased with it. Kept the trailer cozy warm in the Grand Canyon with outside temps in the 30's.

[AnnArborBob]

Originally Posted by BambiTex

Look at my other threads for details. This system uses very little current (6 amps or so) and is very quiet.

Posting a comment about how quiet your heat pump is without explaining that you have a non-standard set-up is misleading and not at all helpful. Expecting people to pour through your "other threads" to get the background is unrealistic.

[55AS]

Originally Posted by AnnArborBob

Posting a comment about how quiet your heat pump is without explaining that you have a non-standard set-up is misleading and not at all helpful. Expecting people to pour through your "other threads" to get the background is unrealistic.

Here is the thread:
http://www.airforums.com/forums/f427...-c-138831.html

[larryglarson]

Wow, lots of ideas. I say if you are on shore cord, use Heat Pump down to 40. You need to try it and make your own decision on cost v/s noise.

[m.hony]

Ditto.
Agreed.
Amen.
And what he said.


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[TCwheels]

Originally Posted by m.hony

It is noisy, by warm.
When I am plugged up at a campground, heat pump costs no more.
If I run furnace, I'm using my propane that I had to buy.
For this reason I use water heater and refrigerator when on shore power too.


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Ditto

[Cyclist]

FWIW - we use two portable electric heaters (one up front, the other in the bedroom) which we set at medium. They are fine to just above freezing at which point we use the furnace.

[Fly at Night]

Hate to say this, but I turned the heat pump on last night for the first time to see if and how well it works before the extended warranty runs out. (Was well above freezing last night). To tell you the truth, I wasn't exctly sure what it was.

Well, it works. A bit noisy yes, but is certainly better than the propane-pig furnace on these not-too-cold winter nights. (The trailer is winterized, but I still sleep in it year round).

Anyway, just happy it works (after five years of never being turned on) and now I know when to use it.

[Adiredneck]

Our usual camping trips to the Adirondacks each June and October usually give us warm (65 degree) days and cool (40 degree) nights. Occasionally cooler, if a cold snap comes through. We use the heat pump (and the electric hot water heater and refrigerator setting mainly because I'm a tighta$$ Yankee and figure I've already paid for electricity as a part of my site rental, whereas propane comes out of my pocket.) The heat pump seems to do fine above 38 degrees. Below that, it seems to work hard with diminishing results. That is where we switch to the propane furnace, especially if it is going to drop below freezing, as the furnace heats the belly-pan and tanks, whereas the HP does not. Our Classic has two HP/AC units, so to reduce noise, I just run the "far" one. During the day, we run the bedroom unit, and at night the rear one, so we don't have a compressor and fan roaring over us. Still beats the crap out of a mummy bag on an air mattress in a two-man pup tent...!

[McDave]

The dog's regular bed is under the table. Unfortunately, so is a furnace duct. When I turn on the furnace on a cold morning, she shoots out of there like she had been shocked with an electric wire! So it would be nice to have an alternative. Actually, I had forgotten about the heat pump, so maybe I'll try using that. Or perhaps a ceramic heater, which sounds like a better idea to me. Unfortunately, both require electric hookups, and we are frequently away from shore power. The ceramic heater would work with the one generator we normally carry. I wonder if the heat pump would work with 1 2kw generator, or if it requires 2 2kw generators, like the AC does? Frankly, the idea of going outside to fire up a generator on a cold morning isn't really appealing to me either, although I'm sure the dog would like it.

[ArtisanAir]

Originally Posted by McDave

I wonder if the heat pump would work with 1 2kw generator, or if it requires 2 2kw generators, like the AC does?

The heat pump would draw the same amount of current as your AC. The heat pump is just your AC running backwards. Same components are being energized, the only difference is a valve positioning.

[Foiled Again]

Originally Posted by BambiTex

I installed a residential "inverter style" split system air conditioner with the compressor mounted on the tongue. It is also a heat pump (reversible A/C) and runs very quietly and uses about 6 amps. Very pleased with it. Kept the trailer cozy warm in the Grand Canyon with outside temps in the 30's.

Oh yes I saw that thread but didn't make the connection. Those are so popular in Europe and elsewhere... wonder why they aren't catching on faster here. Interesting.

Paula

[ArtisanAir]

For a smaller trailer that would be an ideal alternative setup. I've always thought a "small" 13500 unit was still overkill for a globetrotter. Plus you do not see the unit sticking up from the sleek monocoque shape. I would assume you benefit from aerodynamics also, being the unit is streamline with the tv. Put a shiny aluminum shroud around it and you may be a trend setter!

[jcanavera]

Originally Posted by m.hony

Is there an automatic setting?
If so use it.
It will automatically run the heat pump until it is too cold then switch to propane furnace.


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We find that the magic point where the switch over occurs is too low for comfort level. I use the heat pump extensively in spring and fall but once it gets into the low 40's outside, it just takes too long to reach the comfort level we are looking for.

One other situation we learned the hard way is to not leave the trailer on a cold damp day with the heat pump on. We were down in Branson in the fall with occasional showers temps in the mid to low 40's and high humidity. We got back to the trailer after being gone about 5 hours and found it was blowing cool air inside even though the heat pump was running. I went back out and found the outside coils were encrusted with ice. Those of you who have a heat pump know that when the heat pump runs for a long period of time, it occasionally goes into a defrost mode which is supposed to melt any accumulated ice on the outside coils. Unfortunately on this day it looks like the heat pump was cycling frequently but not running long enough to kick in the defrost cycle. It was also cool enough outside that the outside temps weren't melting enough ice that was accumulating during the run cycle. The result was an outdoor freeze up. (picture below).

As far as the noise from the heat pump being annoying. I never considered the fan motor from the furnace being a silent partner. To me it's probably more annoying than the sound of the heat pump.

Jack

[AirEgger]

We have tried the heat pump but find it too noisy as mentioned previously. We use electric space heaters during the day but don't like to run them over night, so we use the furnace. To us the furnace has a softer sound and easier to sleep to.

[Zybane]

Also don't forget running in heat pump mode is also wearing out your AC unit just as fast as "normal" AC mode.

I do have a question about Airstream furnaces. In a park on shore power you want to use shore electric for your heat instead of paying out of pocket for LPG. Can you run the furnace in "fan" only mode? This would allow some of the electric heated air to be forced down to warm the tanks, while not using any LPG.

[dznf0g]

Originally Posted by Zybane

Also don't forget running in heat pump mode is also wearing out your AC unit just as fast as "normal" AC mode.

I do have a question about Airstream furnaces. In a park on shore power you want to use shore electric for your heat instead of paying out of pocket for LPG. Can you run the furnace in "fan" only mode? This would allow some of the electric heated air to be forced down to warm the tanks, while not using any LPG.

I did just such a mod. I'll try and find the thread.

[dznf0g]

Here it is:

http://www.airforums.com/forums/f427...ase-74624.html

[Bigventure]

I place the the thermostat in auto and use the heat pump. But, I open the dump valve on the AC unit. This lets the warm air blow straight down to the floor. Hot air rises so it works better this way. Hot air is forced down to the floor and it will naturally rise back up and be reheated.

The furnace will come on when it goes to freezing. The furnace is what keeps your tanks from freezing. I also added a dampened grill under the rear table to force more air to the front of the trailer. There is no way to balance the furnace heating without dampers on the grills. Air will follow the path of least resistance, so the very short front ducts runs need cut off to deliver more heat to the front of the trailer. You can pick up new dampened grills at good camper stores.

I have a 2013 25 FB Intenational
HVAC pipe fitter for 35 years.