water heater

Turn it on as needed unless it gets really cold then turn on until it warms up outside and then back to as needed. Once it's warmed up it will take a pretty long time to cool it back to freezing. leaving it on all the time will try and maintain 120 (or whatever it is) which will use a lot of fuel and really unnecessary. It only needs to stay above 32 unless you are taking a shower.

njtony wrote:
Only turn on when needed. Just worried that water will freeze in tank and damage tank. Just trying to save propane.

A lot depends on wind and weather.. If it's windy the cold can penetrate the outer panel easier, If it's very cold, say 10 degrees or less. Leave it on, at 20.. Well it is up to you. at 30 I'd not worry much.

If you have full hookups and are NOT paying for electricity, Leave it on electric. If it does not have electric get the Hot Rod add on electric element

if you have full hookups flowing water does not freeze as fast as still water.

If, like me, you have a 3rd waste tank (Black/Gray/Wash) in many areas it is ok to let wash water run on the ground if you do not have a sewer hookeup.. In some places however, it is not (Wash is the rear bathroom Sink and Shower in my Rig, I;m not sure where the washing machine line goes, nor do I care since I do not have the machine).

thanks to all of you for your input.will see what happens. I use propane.for peace of mind I think I will leave it on .I like the dual fan idea.will have to look into that.

eHoefler wrote:
It cost less to maintain temperature than to raise it from cold.

On what do you base this claim?

For a normal water heater, it's exactly the opposite way around, and a simple thermodynamic analysis shows why. The rate of heat transfer between two bodies is proportional to the difference in their temperatures. By maintaining the temperature of the water in the heater at a high temperature, the temperature difference between the heater and the surrounding environment is kept at a maximum, and the heat that escapes from the heater is maximized. If it gets cooler, on the other hand, the rate of transfer goes down and the total heat loss goes down.

It should be pretty obvious that whatever heat is lost is what needs to be put back into the water by the heater, plus some factor for inefficiency in the heating system. For electric heating, the inefficiency is basically negligible; for gas, it's not negligible. (Gas would also be more efficient at heat transfer when the water is cool than when its warm, since the temperature difference between the flue and the water is greater, and then the efficiency drop a bit as the temperature of the water goes up.)

On a quite long term basis, it's very obvious that leaving the water heater on is less efficient than not. If you left it on all summer, say, you'd probably run out of propane in the RV tank; while, with it off, the propane level would not change.

For a heat pump system (such as some residential water heaters use), the analysis may get rather more complicated because the efficiency of the heat pump is not fixed and because most of them have a hybrid system where there's also an electric heating element. A big demand (like heating the tank up from cold) would involve the heating element and extended operating of the heat pump, which would get at least somewhat less efficient as the heat from the surrounding environment is moved to the water. The ambient temperature around the heater goes down, as there's less heat to extract. But this is inapplicable to RV water heaters which don't operate with a heat pump.

Hi,

My water heater did not freeze when the ambient was -37 c (-34 f). It was not turned on. I maintain 20 c (68 f) inside the RV.

Pipes on the other hand must be kept warm. I've replaced the cold air return for the furnace with dual window fans to push warm cabin air through the duct work and under the cabinets.

Please see the winter camping thread under the full time forum for many other cold weather solutions.

It cost less to maintain temperature than to raise it from cold.

Are you RV'ing to save money? Do you turn off your WH in your sticks and bricks house overnight? Don't know about you, I like hot water when I turn the tap on. I like to shower WHEN I WANT to shower, I don't like to wait twenty minutes for the water to heat up. I don't like staying awake at night wondering if my water heater might freeze and cost me $$$$$$$ to fix. Honestly, If you are RV'ing to save money you should probably rethink things a little bit. The cost of heating your water 24/7 is nickles and dimes in the long run, really. YMMV

Mike

If the water is not drawn off, on a ten gallon heater it will cycle every four hours. On electric the "on time" is 15 minutes. That works out to about 1.8 kwh per day.

Lots of good answers, but a few more questions are also in line.

How is your water heater powered? Are you on shore power? How cold is it outside. I have winter camped many times in trailers, pop-ups and Motor homes the longest time length was a month.
Is it a expense issue? , is your unit on gas or power? My current camp buddy has been in his camper as a work camper in an area campground for over 18 months. He has never turned his water heater off. The elements inside the units in a home are not much different than a camper unit and they are never turned off once on and they last years. I replace my first heating element in my unit last year and it was 9 years old.
Look at all the pros and cons and do some test to see what works best for you at the time, but be aware of your units location, and pipes freezing. Happy parking

Or to put it another way:
You should be WAY more worried about water freezing in the other pipes/hoses than in the water heater itself.

The other side of that coin is: Having the water heater hot should help keep other pipes from freezing and once it gets hot keeping it that way shouldn't use too much fuel.