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heat pump doubters

Tested my heat pump operation this morning. Outside coach 45 f, inside coach 48 f. One heat pump on [through ducted air], after 2 hours: outside coach 47 f inside coach 70 f. Current draw pretty steady at 14.9 amps. Will test with plug in cube heater tomorrow if temps are the same.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: heat pump doubters

Reply #1 –
Heat pumps are "rated" at 47, where you will at the very least get $3 worth of heat for $1. They do pretty good until about 38. BTW in Wichita, KS the average winter temp is 48 IRC, areas further south do better.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: heat pump doubters

Reply #3 –
The new Atwood roof air conditioner units are much, much quieter than the Dometic. They use separate fans for the evaporator and condenser.
Jim

2002 U320
Jim Frerichs
2002 U320 42'

Re: heat pump doubters

Reply #4 –
You're putting double the hours on your compressor by running it in the winter as well as the summer. The cost of electricity is small compared to the cost of replacing your expensive heat pump twice as often. If you factor in all the costs a heat pump is by far the most expensive heater you can use... except maybe for leaving your diesel engine running all night in the truck stop like commercial drivers do. A small 1500 watt portable ceramic heater costs about $18 at WallyWorld and will last several years.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: heat pump doubters

Reply #5 –
Quote from: RRadio –
You're putting double the hours on your compressor by running it in the winter as well as the summer. The cost of electricity is small compared to the cost of replacing your expensive heat pump twice as often. If you factor in all the costs a heat pump is by far the most expensive heater you can use... except maybe for leaving your diesel engine running all night in the truck stop like commercial drivers do. A small 1500 watt portable ceramic heater costs about $18 at WallyWorld and will last several years.
I guess  if you get your electricity for free, or it included in your campsite, but the heat pump is twice as efficient as a resistance heater and will heat your whole coach. Cube heaters do fine for your bedroom or close to you in the living room, but put one in your bedroom and try to stay warm in front. Been using heat pumps since they first came out and can not see any difference in life compared to ac units. Heat pumps run exactly the same as a air conditioner but reverse the flow of freon.  If the average ac roof air will last 10 years before replacement, chances are the ac/heat pump will last the same 10 years. Take that 10 years, compare what you pay for electricity for a ceramic heater and what you save using a heat pump and you probably save enough to buy a new ac/heat pump which is only about 20% more than a standard ac.
I have had more than one coach that had ac's over 15 years old, and using them in south texas, that's a lot of use.

Good info on the cost saving. Looks like average is 50%
Electric Resistance Heating | Department of Energy

Of course the drawback is the noise, but if you can put up with it for your air conditioning, you should be able to put up with it for heating, if not, pay the extra money to run your resistance heaters.
Of course, if you have an aqua-hot, or propane furnace, that trumps the heat pump.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: heat pump doubters

Reply #6 –
When I sold my 1994 Bluebird in 2016, it still had the original two air cons.  22 years, with full-timing from 2009 to 2016.

I think I'll be ok using both heat pump and air con.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: heat pump doubters

Reply #7 –
Scott, not only is $18 heater much more practical and lest costly, its heat starts at floor level where heat belongs.  That is compared to heat that starts out at the ceiling level, only to keep most of its heat up there at the cost of not keeping feet warm.  Warm air rises and cool air falls.

Re: heat pump doubters

Reply #8 –
I hesitated to post on this but my guru 17 year repair shop guy who only fixes big things did mention a shorter a/c life on heat pumps.

Not sure if his comment is for all users but for sure it has to apply to heat pump cycle users.

Most of his work is on later model 45'  big coaches and busses. Maybe the somewhat later  units than the average age here have more issues? Or their being used more as some coaches barely have opening windows?

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: heat pump doubters

Reply #9 –
Nice thing about having two ac/heat pump units and two propane furnaces is that most of the time I only need to run one. That one bring in the other end of the coach. Makes the occupied end much quieter.

And I agree, I've had no issues using the heat pump down to 40 degrees.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer

Re: heat pump doubters

Reply #10 –
Just left Texarkana six state rally had to use my Mr Heater two nights.  Ran heat pump for one day then switched.  Just too much noise.  Small heaters worked great in 31 degree temp.
Dan & Shirley Stansel
2002 U295 4020 AGDS Build#6054
Towing Buick Enclave & M &  G Braking
Emerald Bay, Lake Palestine, Texas
MC# 16650

Re: heat pump doubters

Reply #11 –
What kills a/c units is short cycling, as like many things they start on realitivly dry bearings. My home a/c which was intentionally undersized runs about 20 hours a day in the summer, my best guess is that it has over 50,000 hours on the compressor. My coach a/c units were original but my guess is less than 5000 hours.
My coach propane furnaces are about 12 kw output. Comfort is realitive, do what makes you happy without wasting to much energy.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: heat pump doubters

Reply #12 –
Right now 36 degrees outside. Checked coach--64 degrees inside. Heater set to shut off at 64. Regular windows, no dual panes.
One small electric heater on the floor, before the "hump" and one 4-1/2" dia old heater fan mounted up near ceiling pushing air to bedroom & bath. Everywhere temp is same, no stratification or air.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: heat pump doubters

Reply #13 –
Thought I would do same test with 1500 watt ceramic heater. Little warmer today 52 outside, 54 inside coach.
Put heater in bathroom with both doors open,  Heater draw 13.9 amps. After 2 hours, bathroom 71 f., copilot area, 62 f., back of coach, 60 f. Being that the heat pump produces twice as much heat for the same amount of electricity, the temps differences are understandable.
Everyone has their own favorite way of keeping warm, I use aqua-hot most of the time.The reason I did this little test, is a friend in thinking of snowbirding in South Texas in a park where he must pay the electricity. He has cube heaters, heat pumps and propane heat, He doesn't want the hassle of refilling his propane tank so wondered what was cheapest way to keep his coach warm.
Very true hot air rises and cold air falls, but many homes in the south do not have basements and if they have forced air cool/heat hvac systems they are very often placed in the attics and the vents are in the ceilings. Of course almost every walmart, supermarket, or any big box store has to rely on warm air from air handlers in the overhead.

Would not even think of telling anyone how to heat their coach, these are just my observations.
As a previous forum member used to say "Do what makes you happy"
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: heat pump doubters

Reply #14 –
I've been an HVAC journeyman since 1990 and have worked on every generation of heat pumps, including ground source heat pumps. The hours on the compressor are doubled because it's running two seasons per year. This drastically reduces the life expectancy of the unit, which is already more expensive than an ordinary air conditioner. Older air conditioners used to last about 25-35 years. Today's air conditioners only last about 10 years. Cut that figure in about half for a heat pump. The air source heat pumps, like these we're discussing, are by far the least efficient heat pumps. This is especially true in cold weather. If it's snowing, sleeting, or raining outside an air source heat pump will freeze up solid because it blows the precipitation through the outdoor coil, which is very cold. I remember going on a service call and trying to find the heat pump but it was a snowball that blended in with the snow covered shrubs. We only found it because of the noise. When I was in the Air Force we had to bring a heat cart off the flight line and duct the heat onto the outdoor coil of the heat pump to keep it from freezing... then we decided it was more efficient to run the heat duct directly inside the building and turn off the heat pump. One campus I worked at had a bunch of ground source heat pumps but they had to add a dry cooler and run it constantly because the ground temperature was changing over the course of the year and reducing efficiency to the point that it didn't work anymore. The worst part about heat pumps is the discharge air temperature is lower than your body temperature, so it always feels like there's a cold draft blowing across your skin even if the room is at the desired temperature... Anyway, if you like your heat pump enjoy it. Personally I've had entirely too much experience with heat pumps over the years and I don't want to deal with them ever again.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)
 

Re: heat pump doubters

Reply #15 –
Appreciate your observations and experience on a lot of different types of heat pumps Scott.  My observations have only been on the heat pumps installed on motorhomes I have owned and used personally. Only problems I ever had was a bad coil on a reversing valve [$10 part] on a OEM ac/heat pump that had been used year round for 18 years.
I did measure the output temp at vent about 10 ft away from the unit when I was doing the test. 114 f.
Enjoy your walmart heater, and I will enjoy my economical heat pump.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.