Heat pumps - more trouble then they're worth??

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Cant Wait

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Joined
Feb 19, 2010
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726
Location
Jamestown, NY
I keep seeing different threads on the forums where people seem to be having issues with their heat pump not coming on/cycling/not putting out heat or A/C, etc. What is the worth of the heat pumps, or are they more trouble then they're worth?
 
The signicant value I see is that they save propane (filling is often a PITA).

I suspect most problems reported are because people don't understand how they work. It simply reverses the air conditioner so it extracts heat from the outside air and moves it inside. Efficiency is reduced as outside temperatures go down until eventually they become inefficient. Ours shuts down just above freezing.

Usually, they automatically back up with the furnace, and in some cases there may be only one zone controlling the furnace (where there are multiple heating/cooling zones, but only one furnace).

Ours is very nice to have and I don't see any downside.

Ernie
 
When we built our home, we installed a heat pump.  When it died it was one of  the happiest day's of my life.  Constant problems, service people out every spring to fix it.  Never again!  BTW we switched to a high efficiency gas furnace and it is still going strong after 25 years.
A heat pump is nothing more than an AC unit capable of running bi-directional.  Below about 35 degrees their efficiency drops to zero.  Requiring a supplemental source of heat.  Also to work properly, they require hugh volumes of air flow.  This means that even when running correctly the air will feel cool.  Outlet temps are generally 10-20 degrees cooler than a fossil fueled furnace.
 
Remember that almost none of us write in to say how well our heat pumps, macerator pump, day-n-night shades, vent fans, etc and so on are working. The only time you see a post is when something isnt' working. Subjects on here go in cycles. You'll see a bunch of one type of problem then it goes away and another subject becomes popular.

My three heat pumps have worked well all winter and switched over to diesel fired AquaHot heat whenever the temperature got below freezing in southern California in November and December and then again when it snowed in Tucson last month.

Ken
 
As Ernie mentioned I think the problem lies in that folks don't always know how to use them effectively.  Ours are very effective down to about 38-40 degrees and when it gets colder, like others have said, our furnace kicks on automatically, not only to provide heat for the inside; but ours heats our under bay tanks to keep them from freezing.

The secret with heat pumps, as with A/Cs in a motorhome, 5th wheel or trailer, you need to not let the heat or cold get ahead of you.  Playing catch up on either heat or cold makes it harder to reach the temp you want.

We have had our coach over 10 years, with 95,000 miles on it, use our heat pumps and A/Cs a LOT.  Just this year we are replacing our rear Duo-Therm unit because if finally fizzled out.  We are replacing it with the same type we had before.  When they are used correctly, they are very efficient, effective and saves a ton on propane.

One other thing I like about using the heat pumps more than electric heaters is that the heat pumps are ducted in the coach, so the coach stays evenly heated; whereas the electric heaters only heat their surrounding area.

Marsha~
 
Ours have worked great and we would not want to be without them. I agree that many do not know how they work.
 
Cant Wait said:
I keep seeing different threads on the forums where people seem to be having issues with their heat pump not coming on/cycling/not putting out heat or A/C, etc. What is the worth of the heat pumps, or are they more trouble then they're worth?

I have two on my trailer.  They work the way they are supposed to.  Because they are loud I never use them.

I installed a wall-mount recessed electric heater that I use, instead, in those situations where it isn't too cold and we have shore power available.

I wish I had the non-heatpump version of our air conditioners because the changeover valve makes quite a lot of noise when they run in cooling mode.
 
I manage an apt building (soCal) and we have 45 heat pumps on the roof. Most of them are 25-years-old (age of the building). The biggest problem that we have is non-use. There is a switching valve in the unit that must be exercised once in awhile or it freezes up.

The heat pump is one of the most efficient forms of heat that you can have. You just have to be sure to turn it on once a month. Turn it to "Heat" once in awhile in the winter and "Cool" once in awhile during the summer and you will have a lot fewer problems. Non-use is the hardest thing that one can do to any AC unit (heat-pump or not).

There is no reason for the unit to be any noisier in either mode. The switching valve merely changes the direction of the flow of refrigerant. The compressor and blower doesn't know any difference.
 
Wavery said:
The heat pump is one of the most efficient forms of heat that you can have.

Maybe in California.  In Minnesota, among other places, it's too cold for them to be much use.  If you're paying for electricity by the kwh and propane by the gallon the break even point is around 50 degrees, depending on prices, and below 40 degrees they typically don't work well enough to be of much use without supplemental heat from another source.

There is no reason for the unit to be any noisier in either mode. The switching valve merely changes the direction of the flow of refrigerant. The compressor and blower doesn't know any difference.

The Dometic Penguin heat pump I have puts the changeover valve in "heat" whenever the compressor shuts off, which process is accompanied by a great klunk and hissing of refrigerant that would even wake up a locomotive engineer from the golden age of rail.
 
Jammer said:
Maybe in California.  In Minnesota, among other places, it's too cold for them to be much use.  If you're paying for electricity by the kwh and propane by the gallon the break even point is around 50 degrees, depending on prices, and below 40 degrees they typically don't work well enough to be of much use without supplemental heat from another source.

The Dometic Penguin heat pump I have puts the changeover valve in "heat" whenever the compressor shuts off, which process is accompanied by a great klunk and hissing of refrigerant that would even wake up a locomotive engineer from the golden age of rail.
Don't remind me..... please....... I'm from Anoka........

You're right, for home heating cooling a heat pump would need a back-up in cold country. That was already covered.

My point was..... heat pumps are not necessarily problematic and should be a decent heat source for a M/H (other than Minn  ;D).

I have Hydronic Heating in my home:
http://www.hydronicheating.com/

It works off of a small on-demand water heater and pumps hot water though tubes in the floor. Nearly 100% efficient. Again, we live in SoCal but our heating bill in the winter is close to nothing. I don't want to talk about our electric bill in the summer  :eek:.
 
I don't think that heat pumps are any more problematic than a vanilla air conditioner. As others have stated, it is just a very minor variation of an air conditioner.

My two heat pumps work fine, within their acceptable operating range (down to about 36-38 degrees).  The whole system, though, is noisy, whether heating or cooling. Not the pump itself, but the sound of air rushing air through the duct system. The propane furnace is much quieter and also heats quicker, but I pay extra for the propane whereas the electricity for the heat pump is usually in the site rent.

For our Florida stix 'n brix house, I chose a standard a/c with electric heat strips vs a heat pump. It's a bit more expensive to operate in mild weather, but I would have needed auxiliary heat anyway, since we get the odd night in the 20's or low 30's where the heat pump couldn't do the job. If I had it to do over again, though, I think I would choose a heat pump for the main system and supplement it with a portable electric heater for the few very cold nights we get.
 
We had 2 on our class A.  I loved them, and under the right conditions they work like a charm.  They don't work under about 45 degrees F.  But other than that we used them alot, and I miss not having them on our new 5er..
 
Am I to understand the a heat pump wouldn't work well in a cold environment?  I ask due to the fact that I looked into them when needing a new furnace at the homested a few years ago.  I chose a high efficiency gas furnace instead.  Applying the same reasoning to my TT, does the same idea apply?
 
Define cold environment :)  Our heat pumps work just fine down into the 30s and we consider that cold.  If we were wintering in Wisconsin, they wouldn't work most of the time.
 
Heat pumps won't work in Wisconsin? Sure they do. Here's the rest of the story:

Heat pumps exchange heat from the air outside and put it inside, just the opposite of air conditioning when it takes heat from inside and puts it outside. There is a limit to how much temperature difference can be accomplished by the standard heat pump/AC unit. When a heat pump is using outside air around 35 degrees or less, it just can't extract enough heat to keep it 70 degrees inside. That's about a 35 degree difference. If you've ever been in an extremely hot environment, say 125 degrees or so, you know your regular AC can't cool you down to 70 degrees either.

So what do you do for heat? If you're in an area where it gets colder than a standard heat pump can extract enough heat energy from the outside air, you add heat strips, electric resistance heat, to the duct work for the heat pump to augment the heat supply. These can be added to home units and to RV units. The heat strips come on as needed to keep your house comfortable. The heat pump still provides the air movement, responds to the thermostats call for heat, utilizes the ductwork to put the heat where it's wanted, etc. So, your heat pump does work in Wisconsin IF it has been engineered to work in Wisconsin.

Ned is right when he says his heat pumps won't work in extremely cold weather, mine don't either, but it's only because they aren't set up to work in cold weather. They'd work just fine if they were equipped with heat strips.

My Arizona diesel fuel will start to gel in Wisconsin winters too, it doesn't mean that diesel fuel doesn't work in Wisconsin it means that I need to adapt my fuel.

Ken
 
Heat strips are just resistance heating elements and are unrelated to heat pumps or air conditioners.  The only thing they have in common is the fan that moves the air. 
 
The heat strips also come on when the heat pump goes into defrost mode, otherwise it would blow cold air out the ducts. We just replaced ours three years ago after 20 years of use. Replaced not because of defect but we wanted a newer model.

Heat pumps only have a few more operating parts, (reversing valve and check valves) depending on the design. Higher end units are often made so complicated there is a greater chance of something going wrong. The old saying "keep it simple" works. I'm just grateful they don't run on ethanol.

Disclaimer: we live in central Florida where we rarely see 20's in winter.
 
Ned said:
Heat strips are just resistance heating elements and are unrelated to heat pumps or air conditioners.  The only thing they have in common is the fan that moves the air.

I think if you dig a little deeper into how they work Ned, you'll find that the heat strips and the heat pump work off a common thermostat. And the heat strips only provide heat when the heat pump senses that it can't get enough heat out of the outside air (unless you go into emergency heat mode). You'll probably find that the heat strips electricity comes from the same breaker/source as the heat pump, often connected directly to electrical connections inside the heat pumps . You'll probably find that many heat pumps use the heat strips to defrost the heat pump. In fact, you'll probably find that the heat strips used by a heat pump won't work at all unless the heat pump is working and tells them to heat up or you are in emergency heat mode because of a heat pump failure. That is a pretty close relationship IMHO.

Ken
 
We have heat pumps but no heat strips.  Heat strips were an alternative option to the heat pumps, not offered in the same unit.  Ours are Dometic, others may be as you describe, but I've not encountered any in an RV.

The same thermostat controls our furnace, but it's not related to the heat pumps either, other than as an alternative source of heat.
 
Ned said:
We have heat pumps but no heat strips.  Heat strips were an alternative option to the heat pumps, not offered in the same unit.  Ours are Dometic, others may be as you describe, but I've not encountered any in an RV.
Ditto....

I had a small camper with a Coleman roof air that had heat strips. They were just shy of useless. A small electric heater (of the same BTU rating) on the floor is much more efficient because heat rises.
 

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