Propane usage

Old-Biscuit wrote:
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

Looking at the picture above, you can see there is a lot of surface area inside the tank to allow heat to escape into the nighttime air.

If the water is 120 F, then more air will be drafted out, and you will have much more heat loss than if the tank is only 40F. However at night, you will not be able to turn on and off the burner (unless you wake up hourly) to keep the tank at around 40-60F. During the day, if you are diligent, you can cycle the burner for only about 5 minutes per hour, and keep the water in the 40- 60F range to keep it above freezing, and not drop below 30. Because the temperature difference between outside air and tank water is less (at 50F average instead of 130F average) you will save propane. You will have about 1/3 the heat loss with a 50F tank compared to a 130F tank.

But leaving the tank on all the time is the SAFEST way to avoid it freezing and cracking. Otherwise consider draining all the water lines, and then you can shut off the water heater and use portable water jugs for any water use. Then you can lower the inside temps to less than 50F safely without damage to the RV.

However it is much more comfortable to keep it at 65F inside and enjoy the fresh hot and cold water, pay the propane bill, and not worry about pipe damage.

Fred.