Differences between a/c and heat pump??

[Wingate]

Looking at a new 5th wheel. Most all of them I have been looking at have had the standard Dometic 15K BTU and 13. 5 BTU aux. in the bedroom.

One camper that we REALLY like has a 15K BTU a/c heat pump and 13. 5K aux. in the bedroom. What is the difference between the standard 15K a/c and the 15K a/c w/ heat pump. ? Anyone have any first hand experience? cOMMENTS? iNSIGHT?

 

[BIGNASTY]

http://www.differencebetween.net/object/difference-between-heat-pump-and-air-conditioner/



Looked into it for house use when we built our home really dont need either here in MT a HOT DAY IS maybe 90* :-laf

 

[JR]

Long story short in hot weather youve got a/c and in colder weather the refridgeration cycle reverses and puts heat through the coil that sits on top of the bonnet in the furnace. In home units its a pretty conservative form of heat down to the low 30s to upper 20s but beyond that you need an auxillary form of heat (gas, electric, etc)

 

[p-Bar]

I heard it's kind of slow to get it to temp too. But they are supposed to be pretty efficient.

 

[jelag]

Wingate... .

The AC that's in my coach has the ability to add electric heat strips... nothing more than an electric heater to use when connected to shore power... and of course it has the standard gas furnace... I not seen a heat pump, per say in an RV but in fact all it takes is a set of reversing valves for the refrigerant... and a thermostat that can control it. .
A quick search on two web sights didn't turn up a heat pump that I could find... I sure hope they aren't adding the heat strips and calling it a heat pump... On a true heat pump, when the outside temperature drops to a point where the heat pump is not effective it changes modes to an electric heater and powers heat strips in the housing. .

Hope this helps.

 

[Wingate]

We camp year round, although the winters here in texas are relatively short, it would save on propane usage. The 5er also has the electric fireplace, between the two, it may keep the gas furnace from coming on at all. . wonder how much propane I would ahve to consume to justify the costs... hhmmmm.

 

[JR]

The a/c function of a heat pump should cool just the same as a comparable condenser that is a/c only. With the heat pump, the colder it gets the less efficient they are and the more they will run to try to maintain the thermostats temp setting. The way they work they draw the ambient air from outside and heat the coil then the fan in the furnace expels the hot air through the ductwork. So in moderately cool climates like say in the 40s and low to mid 30s an appropriately sized heat pump will keep a home at 72* all day long and do it very efficiently. But once you start dropping below 30 and colder they have to work harder to make that same 72* air. Most heat pumps will kick off at around 25-28* and the auxillary heat will kick in whether it be gas, elec, heating oil, etc. I installed one at our last house and I really loved it. It doesnt run so much in the winter but we have a full 2 seasons in fall and spring where the heat pump is right in its prime efficiency of 30* and warmer. It cut our heating oil bill in more than half, and the electric bill increased only marginally considering what we saved on the other end. Our new home has a gas furnace and was brand new when we moved in 2 years ago but once I finish replacing all the windows in the house Ill be adding a heat pump to cut back on the usage of gas

 

[BIGNASTY]

Mr Wingate



Hope this helps we are scribed to this magazine for obvious reasons and knew that I had recently read something about heat pumps. Again I hope it helps



http://www.homepower.com/articles/ask-experts-heat-pump-garage



BIG

 

[Bill Stockard]

I've never owned a heat pump in an RV, but we have two heat pumps heating our house and they do a very good job heating down to the single digits. As the temperature gets down in the lower teens and below, they run a little longer to maintain the set temperature, but the emergency/auxiliary heat strips don't come on to assist. At those temperatures, if we bump the thermostat up two or more degrees, the heat strips will assist the heat pump until the temperature gets to within one degree of the set temeprature and them the heat strips cycle off and the heat pump compressor does the rest. The air from the heat ducts always feels warm. Our winter electric bill averages $150 per month which includes two electric water heaters, two clothes washers and dryers, three fridges, and one freezer.



Bill

 

[Bill Stockard]

Wingate... .

The AC that's in my coach has the ability to add electric heat strips... nothing more than an electric heater to use when connected to shore power... and of course it has the standard gas furnace... I not seen a heat pump, per say in an RV but in fact all it takes is a set of reversing valves for the refrigerant... and a thermostat that can control it. .
A quick search on two web sights didn't turn up a heat pump that I could find... I sure hope they aren't adding the heat strips and calling it a heat pump... On a true heat pump, when the outside temperature drops to a point where the heat pump is not effective it changes modes to an electric heater and powers heat strips in the housing. .

Hope this helps.

Jim,

These are real heat pumps: http://www.dometic.com/enus/Americas/USA/RV-Products/climate/ac-display-page/?productdataid=66936
They reverse the refrigerant flow during the heat cycle. Notice the "30 degrees and above" disclaimer.

Bill

 

[crispyboy]

We had a heat pump made by Carrier in our first Airstream trailer. It works just as others said in the previous threads. I can't remember for sure but it may also have had some auxilliary heat strips to help out the heat pump when it was getting closer to 30*. It seemed to work nicely especially when it was cool and damp - 50* - rainy (too warm for a furnace). It took moisture out of the air and made it comfortable.

 

[Bill Stockard]

We had a heat pump made by Carrier in our first Airstream trailer. It works just as others said in the previous threads. I can't remember for sure but it may also have had some auxilliary heat strips to help out the heat pump when it was getting closer to 30*. It seemed to work nicely especially when it was cool and damp - 50* - rainy (too warm for a furnace). It took moisture out of the air and made it comfortable.

RV heat pumps are quite common on RVs used by retirees overwintering on the the Lower Texas Gulf Coast and the Lower Texas Rio Grande Valley where the temperature rarely drops below 30 degrees.



Bill

 

[BIGNASTY]

I've never owned a heat pump in an RV, but we have two heat pumps heating our house and they do a very good job heating down to the single digits. As the temperature gets down in the lower teens and below, they run a little longer to maintain the set temperature, but the emergency/auxiliary heat strips don't come on to assist. At those temperatures, if we bump the thermostat up two or more degrees, the heat strips will assist the heat pump until the temperature gets to within one degree of the set temeprature and them the heat strips cycle off and the heat pump compressor does the rest. The air from the heat ducts always feels warm. Our winter electric bill averages $150 per month which includes two electric water heaters, two clothes washers and dryers, three fridges, and one freezer.



Bill

Dont mean this to be mean or derogatory but $150. 00 per month WOW!! I asked the wife about ours when we lived here in So Calif. ours was about $65. 00 per month. We didnt heat with elect or water heat or the 3 fridges. Our Pool,hot tub were our big users but the pool was on Solar heat. Compared to now in Montana that just floors me even ours in So Cal looks out of control NOW!!! I GUESS IT ALL ADDS OUT TO BE ABOUT THE SAME. I would HATE to know what elect in MT would be if we lived ON GRID.

 

[Bill Stockard]

Dont mean this to be mean or derogatory but $150. 00 per month WOW!! I asked the wife about ours when we lived here in So Calif. ours was about $65. 00 per month. We didnt heat with elect or water heat or the 3 fridges. Our Pool,hot tub were our big users but the pool was on Solar heat. Compared to now in Montana that just floors me even ours in So Cal looks out of control NOW!!! I GUESS IT ALL ADDS OUT TO BE ABOUT THE SAME. I would HATE to know what elect in MT would be if we lived ON GRID.

Maybe it's warmer in the winter in So CA than northeast Texas... but horses couldn't drag me there to find out!!:-laf



Bill

 

[HBarlow]

SoCal winters are most definitely warmer than all of Texas except the Valley.

 

[BIGNASTY]

Maybe it's warmer in the winter in So CA than northeast Texas... but horses couldn't drag me there to find out!!:-laf

Bill

Im trying to get the WIFE out of here!!!! Thanks for the idea Ill have to see if I can find a few horses SHE'S SHOPPING SO THEY WILL HAVE TO BE DRAFT HORSES FOR SURE!!!!

 

[JJPage]

We had a heat pump made by Carrier in our first Airstream trailer. I can't remember for sure but it may also have had some auxilliary heat strips to help out the heat pump when it was getting closer to 30*.

You can almost bet it did have auxiliary heat strips, or it would be blowing cold air into the conditioned space during the defrost mode. When in defrost mode, the unit has to go back into the cool cycle to melt the accumulated ice off the condenser, at that point the strip heat actuates to temper the cold air being pumped into the occupied space.

I would not want a heatpump for an RV application (my home yes), in the heat mode the unit runs at higher pressures than in the cool mode, using more energy and causing more wear (the colder the ambient temp the harder the unit has to work). The condenser coil would have to be much larger to be efficient, especially as you reach less than 40*F. The electronic controls have to be more sophisticated to operate it, t-stat, defrost timer, freeze sensors, reversing valve, to name a few. Plus it has to have strip heat to counter the situation I explained above, so I would opt for a larger internal strip heat and pass on the heatpump version.

Jess

 

[JR]

I've never owned a heat pump in an RV, but we have two heat pumps heating our house and they do a very good job heating down to the single digits. As the temperature gets down in the lower teens and below, they run a little longer to maintain the set temperature, but the emergency/auxiliary heat strips don't come on to assist. At those temperatures, if we bump the thermostat up two or more degrees, the heat strips will assist the heat pump until the temperature gets to within one degree of the set temeprature and them the heat strips cycle off and the heat pump compressor does the rest. The air from the heat ducts always feels warm. Our winter electric bill averages $150 per month which includes two electric water heaters, two clothes washers and dryers, three fridges, and one freezer.



Hey Bill, Im surprised your unit can make heat down to those cold of temps with no assist from the auxillary, that makes my above post inaccurate. Sounds like theyve come a long way in technology since I purchased mine 7 or 8 years ago. We bought a Carrier which was one of the better models you could get at the time

 

[JJPage]

We had a heat pump made by Carrier in our first Airstream trailer. It seemed to work nicely especially when it was cool and damp - 50* - rainy (too warm for a furnace). It took moisture out of the air and made it comfortable.

crispyboy, glad you were happy with the heatpump in your Airstream, that's the bottom line, is the consumer satisfied.



Just to clarify on the heatpump operation, they do not remove moisture from the conditioned space while in the heat mode, only during the cool mode. While in the heat mode, they are absorbing heat from the outside air, causing water condensation on the condenser (outside) coil, and if below 32*F, to freeze. Just the opposite in the cool mode, where the evaporator coil is absorbing heat from the conditioned space, removing moisture and requiring a condensate drain or pump to expel the water.



I have an old R-22 Carrier heatpump at my present home, it has a reciprocating compressor so it's not really efficient in the heat mode, used mostly for A/C in the summer, have a gas fired hot water boiler for heat. The new scroll compressors are much more efficient, I am not sold on 410A as a superior refrigerant though. I am going to install a heatpump in our new home, a friend purchased a quanity of R-22, scroll compressor units when a local supplier unloaded them due to municipal codes requirements... Sanders County MT has no such nonsense. Jess

 

[Wingate]

Thanks to everyone that responded... gonna go look at it tomorrow. gonna try and get some more specifics on it.