Sandy Korners
Marathon, FL
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Can anyone explain how a heat pump works? How does it cool my motor home? Then how does it heat it?
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bsinmich
Holland, MI
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A heat pump is an Air conditioner working in reverse. An AC takes the heat from inside the MH and expells it outside. When used as a heat pump the heat is removed from the outside air and expelled through the AC outlets. That is why they don't work as good when outside temps get below 40F. Thed whole process used the expansion of a gas to absorb heat and move it to another location.
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Bumpyroad
Virginia
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Sandy Korners wrote:Can anyone explain how a heat pump works? How does it cool my motor home? Then how does it heat it?
they work sort of like a thermos bottle. It keeps hot things hot and cold things cold, but How does it know?
basically a heat pump as in a home unit just reverses the process. takes "heat" from air up to about 40 degrees, in theory. IMHO they suck. I have had about 7 of them over the years in my houses and they suck compared to oil/gas/electric heat. the only time you get hot air out of them is when the heat pump function turns off and the backup heat kicks in. air coming from them is about 85 degrees and you feel a cool draft when sitting in the air flow.
when the electric coils kick in it goes up to 105? or so and at last you feel warm.
those who paid to have them in their rvs seem to swear by them. don't know how a RV unit could work better than one in the S&B however.
in my opinion they rival the so called "heat strips" that you can get in an AC unit, and they are less effective than a $17.00 ceramic cube heater.
bumpy
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docj
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Heat pumps are used in both regular homes and in RVs for both heating and cooling. Basically, it is just an air conditioner that has a reversing valve that enables it to work "in reverse." An air conditioner takes heat from inside your house and puts it outside (that's why the outside fan on an a/c feels hot).
When it is operating as a heat pump it takes heat from outside and puts it in the house. When it is cold outside you might not think there is any heat there, but there is (you can always make it colder). So the heat pump extracts this small amount of heat and "stuffs" it into your home or your RV. The efficiency of a heat pump decreases as the temperature falls and when it gets to freezing temps outside, it isn't of all that much use.
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RRTom
California USA
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Bumpy,
Here in CA the heat pump does a good job of heating, however it (like the AC) is noisy so we prefer the gas heater.
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Sandy Korners
Marathon, FL
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Thanks everyone. No I know.
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Sandy Korners
Marathon, FL
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That should have been now I know
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Executive
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Glad you've already received a very thorough answer....I always thought they worked by MAGIC...kinda like a Ouija board..... ....Dennis
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Lady Fitzgerald
Tempe, AZ, USA, Earth
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Bumpyroad wrote:Sandy Korners wrote:Can anyone explain how a heat pump works? How does it cool my motor home? Then how does it heat it?
they work sort of like a thermos bottle. It keeps hot things hot and cold things cold, but How does it know?
basically a heat pump as in a home unit just reverses the process. takes "heat" from air up to about 40 degrees, in theory. IMHO they suck. I have had about 7 of them over the years in my houses and they suck compared to oil/gas/electric heat. the only time you get hot air out of them is when the heat pump function turns off and the backup heat kicks in. air coming from them is about 85 degrees and you feel a cool draft when sitting in the air flow.
when the electric coils kick in it goes up to 105? or so and at last you feel warm.
those who paid to have them in their rvs seem to swear by them. don't know how a RV unit could work better than one in the S&B however.
in my opinion they rival the so called "heat strips" that you can get in an AC unit, and they are less effective than a $17.00 ceramic cube heater.
bumpy
The thermos bottle analogy is totally bogus. Docj and bsinmich explained the process quite well.
A heat pump is far more efficient than a heat strip or any other form of resistance heating. Technically, heat pumps re more efficient than gas heat, however gas is usally sufficiently less expensive than electricity to make gas heat less expensive than any form of electric heat. Electric heat becomes advantages when gas is unavailable or is difficult or expensive to obtain. an example is when staying in a campground that charges a flat rate per night for spacerent and electricity. Full timers staying long term in parks may find it less expensive and/or more convenient to use electric heat, especially heat pumps.
I installed a residential heat pump on a large mobile home back in the '70s and it worked just fine in temperatures down to the mid-twenties without a heat strip. It put out plenty of hot air. If you had trouble with the seven heat pumps you say you had, they were inferior units, improperly sized, or the installers didn't know what they were doing.
I see figures of 40-45F being thrown around on the RV forums as being the low cut off for efficient operation but Dometic advertises their units being efficient down to 32F. I also read a post from someone who has a Dometic heat pump and he reported it worked fine down to 32F, after which the thermostat switched in the propane furnace.
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Dale.Traveling
Newport News, VA
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Have a heat pump with the house in Newport News VA along with a natural gas furnace. Works very well down to about 30 degrees then the furnace kicks in. Electricity has been cheaper to heat with up until very recently. With the price of natural gas dropping my cost savings may shift.
The strangest application I've seen is a heat pump water heater. Very expensive. Didn't get past the base price to take into consideration the energy savings.
I'm waiting for the AC on the coach to die so I can replace it with a heat pump rather than using propane for those cool spring and fall outings. Wouldn't consider the heat pump as a complete replacement for the propane furnace though.
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