Propane usage

Try adding electric heating to the water heater. Ours is a 6 gallon Atwood and uses propane or 120v. Eliminate the propane usage.

Dave

I have an external 150 gallon propane tank that I use in the winter since I don't want to have to change the small tanks frequently. I'm NOT in the extreme cold areas as others, but I do leave my water tank on all the time. It just isn't worth the risk when it does get down into the teens.

Hi,

There are 50 pounds of water in a 6 gallon heater. If the heater cycles to off at 140 degrees F, then it would require a heat loss of about 5400 btu's for it to freeze. The heater is exposed on only one side to freeing temperatures.

If the interior of the RV is kept at comfortable levels then even at -30 it would take a very long time for the water heater to freeze. I know that mine, which is a ten gallon unit, will not freeze at a daily high of -16.6 F during a 5 day trip.

What size propane cylinder/tank----gallons??
In those temps you are getting up to a week on propane use then you are doing GREAT? Unless you have a motorhome with a large propane tank

In -14*F temps we had to get a 30# (7 gallon) filled every other day

'Golden_HVAC' makes a good point about the design of RV water heater.
That combustion chamber is wide open and runs up thru tank sucking cold air in/around water inside tank

That's alot of surface area in contact with the water.

In (-)degree temps I wouldn't experiment and just pay for the propane

Hi,

If it is -10F outside, then you need to keep the water heater on all the time to keep it at least over 40F all the time (so unless you plan on getting up every hour at night, just leave it on.) You can shut it off during the time you can monitor the water heater temp, at at least run it every hour or so for 5 minutes. however the burner is only 8,800 Btu's and can run 11 hours burning only 1 gallon of propane. Most of the time the burner is not on all the time, so it is off more than on, so 11 hours might take 2 days to use 1 gallon, perhaps 4 - 10 days in the summer when cold air is not robbing most of the heat out of the water heater.

You can leave the water heater off all the time it is warmer than 30F outside, but colder than that temp will cause the water to quickly freeze inside the tank, and damage the $400 tank. No savings there. There is a huge flue pipe going through the center of the water heater tank that will quickly let 25F air through the tank and freeze it faster than even a glass of water or dog dish left outside.

The furnace can use 40,000 Btu's per hour, there is 95,000 Btu's in one gallon of propane. So you can run the furnace for 2.2 hours per gallon. The stove burner is about 9,000 - 12,000 Btu's on high heat setting while a RV oven is around 18,000 - 22,000 Btu's. Home ovens have about 30,000 Btu oven burners.

My guess is most of your propane use is through the furnace. If you plan on staying in one place for a long time, then consider a 100# tank that is refilled at your site.

What I did while living in my motorhome in Portland OR in the winter of 2008 was run 3 electric heaters. I have a 30 amp 120 volt service, and ran 2 heaters on low heat setting. The third heater I would run on a #12 gauge extension cord and could run it on high (1,500) or low 800 watt setting. I also used a electric mattress warmer, and my lowest outside temps where only 26F, so not nearly as cold as you have.

I used bubble wrap insulation (Reflex) in my windshield, and most of the outside windows. This helps slow the heat loss. You can get this at Home Depot / Lowes. Look for it in 24" and 48" wide rolls. I had bought a 48" X 75' roll from a HVAC contractor supply house. You can buy 24" wide X 25' or so at Home Depot, and use that to place between the ground and RV sidewalls. This will keep air from blowing under the RV, and thus will stay warmer.

Camping World also sells a lightweight pillow that goes into a 14" square roof vent, and helps insulate it from the cold coming in.

Fred Golden.

Hi camper,

The water heater supply pipes are inside the RV not outside. Golden intends to continue to use the water heater--just not run it full time.

I have no experience with living in such cold weather but I would be worried about the water heater pipes freezing. With the heater being open on one side to the outside something just may freeze. Could you turn the heater on for maybe 30 minutes a couple times throughout the 24hrs? In my opinion the use of more propane highly out ways the potential of having frozen pipes.
just my $.02

Hi Golden,

Welcome to the forums.

I did a "back yard" experiment on my water heater. The ten gallon unit cycles every four hours and it takes about 15 minutes to shut off again. That means in 24 hours of NO water being drawn the heater runs for 1.5 hours.

My conclusion was that it was best to turn it on until it reached full temperature--then shower. After the shower I turn ig off and there is enough water to rinse my hands, and do dishes for the day.

Another friend did a month long experiment where she left the water heater running--and the month after she turned it on only "as necessary". Her propane use dropped dramatically in the second month.

BTW have you looked into renting a larger propane tank for the winter?

You might also want to consider a Platinum Cat because it is inherently more efficient than the propane furnace. It is vented and has a thermostat. Platinum Cat

I ran another "back yard" experiment two days ago starting with my RV at -20 C when the ambient temperature was -30 C. If you wish to see the results surf here:

Heating Electrically a "back yard" report

Mine seems to use a lot. But as pawpaw says, be sure it wont freeze

There was a post on a thread recently about that. The fellow seemed to think it helped quite a bit.

I'm in the camp - leaving it on all day takes more energy than just heating the water when you need it.

The only thing I'd wonder about is where is the WH located - can you make sure the input and output water lines stay warm?

The water heater does have a direct opening to the outside temps, and metal conductive from the anode to bring the cold into the tank. Maybe a small electric heat pad to help keep the tank near the outside warmer.

Some others will add more ideas soon.

Not really my thing - you ain't never gonna find me camping at -31, no - change that - you ain't never gonna find me at -31 period.