Air conditioner with or without heat pump recommendations

[Ornstream]

We are now looking at replacing the air conditioner on our 2002 CCD 22ft International and are debating the usefulness of the extra price of getting one with the heat pump. Any input out there on how useful it is? Is it more useful than just using the propane furnace?

As you may guess we are beginners!

[m.hony]

Yes to the heat pump.
When you are in a campground, you are hooked to electricity- doesn't cost you any more to run the heat pump-
If the propane furnace is all you have, you use up your propane, which you have to pay extra money to refill-
Below freezing you will use the propane furnace, anyway, as heat pumps don't work at really low temperatures.
Before we had heat pumps we used electric space heaters.
Just my 2 cents, for what it's worth-

[Wingeezer]

I don't know the price differential because we bought our AS used, so it is hard for me to assess merit vs cost.

This is the first trailer we have had with a heat pump. At first I was a bit reluctant to use it for fear of shortening the life of the AC ! Probably not a reasonable concern, and maybe in fact it is good to keep things working in the AC!

In reality we find we use it far more than we use the furnace. In fact about the only time we use the furnace is if we are not connected to 110, or if the temps are really cold - down around freezing, where the heat pump ceases to be of much use.

If temps are in the forties though, it seems to work just fine.

Also you are using the AC you have aid for rather than your propane!

I would be inclined to buy an AC with the heat pump - unless the extra cost is exorbitant.

Finally, with both the furnace and heat pump, you have a backup situation if one should become defective

I think another option that could be a compromise and still offer some benefit but possibly at lower cost is a heat strip installed in the AC - I am assuming this is still offered as an option.

The controls on one of our earlier trailers had this switch position, but the regional purchaser never had the heat strip installed I don't believe.

Brian.

[Phoenix]

* A heat pump works well for cold temperatures mostly above freezing. It is electrically more efficient than resistance heaters that provide the same amount of heat, but the compressor is relatively noisy (same as running the air conditioner in the summer).

* Most air conditioners can be equipped with an optional (internal) heating element that provides a small amount of heat, mostly for taking the morning chill off in cool weather. It can also provide supplemental heat in subfreezing weather. However, it usually won't replace the propane furnace due to lower output; as the heat provided is similar to a small 1,200 to 1,500-watt space heater. However, we have run the air conditioner heating element 24/7 in sub-freezing weather with good results in our 19-foot Bambi. This might not work as well in a significantly larger RV. Note: Although, the heating element is usually optional, our air conditioner came with it already installed when we purchased our Bambi new in 2005.

* The propane furnace provides the most heat; but in sub-freezing weather, it will go through a single propane tank every 2-5 days, depending on the size of your Airstream and how high you set the thermostat. We had to refill one 30 pound tank every 3 days in 40/10 degree (day/night) temperatures, with thermostat set at 65 degrees for a couple of hours in the morning, thermostat turned off during most of the day (while we were gone), 65 for a couple of hours in the evening, and 50 (lowest setting) overnight. This was in Denver, so your propane usage may be higher.

Just my personal opinion, but due to some negative comments regarding heat pumps (mostly noisy and ineffective in sub-freezing weather), I would get an air conditioner with optional heating element; and I'd use the furnace as my primary heat source.

[mojo]

Originally Posted by Ornstream

We are now looking at replacing the air conditioner on our 2002 CCD 22ft International and are debating the usefulness of the extra price of getting one with the heat pump.

Only if it comes with ear plugs...

Never use it.

[Pahaska]

Originally Posted by Phoenix

the compressor is relatively noisy (same as running the air conditioner in the summer.

What you are hearing is fan noise and the rush of air, not the compressor. When the heat pump goes into defrost with the fan off, there is only an unobtrusive hum from the compressor. When the defrost cycle ends, there is a brief noise as the solenoids switch back to heat pump mode.

The Dometic units are natively heat pumps and must be switched to AC mode every time they start up in summer. In a prior Airstream, I had a unit that sometimes failed to switch to AC. The AC unit was replaced twice and the thermostat was replaced without success. We travel with cats and I finally traded up to my present 28 since no one could solve the problem. The heat pump would kill the cats in a few minutes in hot weather. In retrospect, I believe I had a bad microwave that was emitting RF into the adjacent thermostat. The microwave was the only thing not changed.

[m.hony]

You hear the compressor, too...

[lewster]

Originally Posted by Pahaska

What you are hearing is fan noise and the rush of air, not the compressor. When the heat pump goes into defrost with the fan off, there is only an unobtrusive hum from the compressor. When the defrost cycle ends, there is a brief noise as the solenoids switch back to heat pump mode.

The Dometic units are natively heat pumps and must be switched to AC mode every time they start up in summer. In a prior Airstream, I had a unit that sometimes failed to switch to AC. The AC unit was replaced twice and the thermostat was replaced without success. We travel with cats and I finally traded up to my present 28 since no one could solve the problem. The heat pump would kill the cats in a few minutes in hot weather. In retrospect, I believe I had a bad microwave that was emitting RF into the adjacent thermostat. The microwave was the only thing not changed.

John,

Interesting that you could not find anyone to diagnose your heat pump problem. You need to find better techs!

Actually, they work like this:

• the flow of the refrigerant is governed by a 'reversing valve' which is solenoid controlled
• this valve is normally in the 'heat pump' mode when in the un-energized state
• to get your unit into the cooling state, this reversing valve must be energized by the control board, which receives a digital signal for cooling from the thermostat
• in cooling mode, the coil that is inside becomes the evaporator and gets cold and the outside coil gets hot (condenser)
• in heating mode, the inside coil is now hot as it has become the condenser due to the reverse flow of the refrigerant and the outside coil is now cold as it is now the evaporator

Did anyone check the solenoid on this reversing valve to observe if it was in the wrong position when you had heat when you called for cooling?

It is a rather simple matter to charge this solenoid. OTOH, if the problem was a sticky reversing valve which is controlled by this solenoid, they CAN NOT be changed and the entire upper unit must be replaced.

Just my 2¢

[Wingeezer]

Originally Posted by mojo

Only if it comes with ear plugs...

Never use it.

Agreed, ac and heat pump can be noisy - but I have a bad habit of falling asleep with Bose QC-15 noise canceling headphones on! they put me in my own little word of silence! Expensive, but the perform as promised!


Brian.

[m.hony]

Maybe I'm half deaf anyway, but-
It ain't that much louder than the propane furnace.
The units in the Airstream are much louder than the unit in our previous sob trailer. Maybe because it was ducted. Airstream could have ducted air. The Land Yacht concept trailer did.

[Pahaska]

Originally Posted by lewster

John,

Interesting that you could not find anyone to diagnose your heat pump problem. You need to find better techs!
Actually, they work like this:

I know how they work. I did a lot of digging and electronics was my business before retirement.

Basically, I think Dometic is stupid in making the heat pump the native operation. In case of a switchover problem, cold air will not kill my animals.

The techs that worked on it included the Dometic rep at the International Rally and two dealers. The AC was replaced twice under warranty. Tests indicated that the control boards were damaged, causing the solenoids to unreliably switch over to AC mode.

I developed computer electronics for IBM for 35 years and debugged new machines in the lab for many years. There are really only 3 elements to consider, the AC, the telephone cable, and the thermostat. Airstream wads up many feet of the telephone cable behind the microwave which is a terrible idea. I would bet on a RF problem injected into the unshielded telephone cable by the one thing not changed; the microwave.

By the way, I have a ferrite core filter installed at the AC end of the telephone cable on my current A/S. Better safe than sorry.

[perryg114]

I don't see the advantage of a heat pump over a heater kit. The heater kit is simple and when it is running the compressor is off. It will keep my 31 foot trailer warm in 30 degree weather. My Briskair heater did not include a thermostat so it is on or off. I ended up putting a base board heater thermostat on there and that solved the problem. I can't imaging that a heat pump would use much less electricity than the 1600W heating element. I lived in a 27 ft 5th wheel in Gainsville,FL and the heater coil on my Coleman kept the trailer warm all winter in FL. It had a two way thermostat that Dometic should have used. Shame on you Dometic.

Perry

[87MH]

Originally Posted by Ornstream

We are now looking at replacing the air conditioner on our 2002 CCD 22ft International and are debating the usefulness of the extra price of getting one with the heat pump. Any input out there on how useful it is? Is it more useful than just using the propane furnace?...As you may guess we are beginners!

It really depends on your preference. I have lived in the '78 for months at a time in both summer or winter so I have some experience in this area. Living or camping comfortably in an AS in the deep South really requires two roof mounted AC's. Two AC's require a 30 amp PLUS a 20 amp service.

I have found that the Heat Pumps work well even when the temps are in the mid 30's.

With a total of 50 available amps you could easily run three 1500 watt heaters, but the heaters take up valuable space and there is always the problem of possible combustion (especially with pets around).

The frequent changing of the propane bottles when using the furnace as the sole source of heat is a huge inconvenience to me.

For my usage, more or less full timing in only moderately cold but very hot conditions, the dual AC - Heat Pump was the ideal solution.

Your results may vary.

I need to also point out that I have a small propane powered catalytic heater installed at the door of the '78. It provides as much heat as a small electric heater, takes up almost no useable space, uses very little propane, and is entirely noiseless. Combinations of various sizes and numbers of catalytics may well be the ultimate solution for your dilemma. You always have the furnace for really cold conditions when and if you encounter them.

Both the '78 trailer and the '87 MoHo originally were equipped with heat strips, I don't remember the BTU rating of the heat strips, but it seems as if the heat output of the Heat Pumps is greater than the electrical resistance strips. Look at the BTU rating of the heat strip prior to making a decision.

Your unit is much smaller than the '78, so you may easily stay comfortable with one unit.

[moosetags]

We have done a lot of camping in our two Airstreams (1,300+ nights) over eight years. Both have had 13,500 BTU ac/heat pump units. We have used the heat pump function extensively. Our heat pump is running as I write this as it is 38 degrees in Jacksonville this morning where we are camped.

The furnace works well also, but the heat pump has saved us a lot of LP gas over the years, and probably hundreds, if not thousands of dollars.

I would not buy a unit without a heat pump.

Brian

[Ornstream]

Thanks for all the input! It was very helpful and it made us think about the way we will be using our Airstream...In the end we decided to have just the regular air conditioner installed and we will get an electric heater to plug in on the days we need it and have electricity.

Any recommendations on heaters? Our camper is so small we really won't need too much power

[BAB]

I use the heat pump when I'm hooked up for the same reason as everyone else. Propane hassle. I've gotten used to the noise. RE: heater. Also have one of the Dyson heaters. It is not cheap, but it really works well. Thermostat is accurate, it oscillates, and puts out an amazing amount of heat. Used it last week in FL when it was down in the 40's and it kept my 28' very comfortable.

[overlander63]

We like the oil-filled electric radiator heater for our Airstream in cool weather. Simply plug it in and turn it on, and it puts out three selections of silent heat on a thermostat. IIRC, it's 600, 1200, and 1800 watts.

[mojo]

A simple ceramic heater with an adjustable thermostat works fine ($30-$40) and can keep the trailer warm all night. Best of all they are very quiet (without fan).

[Jammer]

Originally Posted by mojo

Only if it comes with ear plugs...

Never use it.

This.

I installed a separate electric heater, which is quiet. I never use the heat pump.

[Jammer]

Originally Posted by Ornstream

Any recommendations on heaters? Our camper is so small we really won't need too much power

If you have the wall space for it, I recommend the King Electric pic-a-watt. It is permanently installed, and is therefore safer, since an installation location can be chosen where there are no hazards from curtains or other combustible materials coming in contact with it, and since the hazards with cords and plugs are eliminated.