I am curious, has anyone done the numbers, what is the most efficient way to heat water, leaving the LP on all the time or turn on XX amount of time before use each day. Was sitting out side my coach one afternoon noticing how many times it turn on an off to keep the water hot.
Water heaters use a lot of unnecessary propane and/or electric if you also have a heating element in it. I recommend buying a 30 minute Potentiometer timer (maybe a 60 minute timer for 2 people) and cranking it up about 10 minutes before you are ready to shower. That is what I did and it saved me trips to the Propane filling station and also some electricity as I also had the 110V element in mine.
We turn ours on 10 minutes before we need hot water works for us
Same as Clifford And turn Water Heater switch off when we are done. We leave the LP tank on when parked unless we need the force air heat traveling.
Same here,, 15 minutes before use and kill it after,, it will stay hot for most of a day or night.>>>Dan
Our 12 gal water heater has an engine coolant loop inside it to heat the water while travelling.
Often I'll forget to turn on the electric element when we park for the day. After washing evening dishes, there will be enough hot water left over for my morning shower. If the wife washes her hair, she will will be lucky to have a luke-warm rinse.
Takes almost an hour to recover with just the electric element.
You can change to a higher wattage element for faster response.
Running our 6 gal Atwood on Ac it uses about 2 KW/day with normal use (no showers but lots of dishes and handwashing) at 45°F ambient outside temp.
HTH Will
Um, doesn't the thermostat on the water heater perform the same function? It turns off when temp is reached. Temp maintains for a long time (at least on my rheem). I can go three days with the water heater off before I feel cool water in the hot tap. I only turn mine off when on genny. The rest of the time I just leave the thermostats to do their job. No need to add more switches to it in my setup.
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A 40 gallon water heater is pretty large compared to most coaches. No wonder it can go 3 days. The internal thermostat will kick on sooner than a timer, so will be on sooner than needed.
Quote from: Scott & Heather on January 01, 2018, 09:39:34 PMUm, doesn't the thermostat on the water heater perform the same function? It turns off when temp is reached. Temp maintains for a long time (at least on my rheem). I can go three days with the water heater off before I feel cool water in the hot tap. I only turn mine off when on genny. The rest of the time I just leave the thermostats to do their job. No need to add more switches to it in my setup.
I have an Atwood 10 gallon water heater. It heats off a 120V coil, propane, and has a heat exchanger coil. If you keep the electric or propane switched on, it will rise to about 190º internal temperature. It has a built-in "tempering valve" that mixes outside water with water from the heater tank to supply water at a temperature of about 118º. I'm not sure how many mixed gallons I get, but it's a lot. Also, the hot water from the heat exchanger is "free" heat if it's come from the engine cooling system while traveling; since it's also regulated to 190º, there's no difference to the temp of the water inside the bus, no subjective feel that there's any difference, and the same amount of mixed-temp water. It also seems to be insulated pretty well.
(Washing machine manufacturers recommend a temperature of about 160º for sanitizing during washing cycle with antiscald or tempering valves at other fixture locations but I don't have a washing machine on my bus. I like the 118º setting OK.)
This works well for me; since I'm often alone or only with my wife, it would probably be different for larger families or others may need or prefer something else, but that's "doing it my way".
HTH. BH NC
I have 2-10 gal electric water heaters that I bought at HD in 1993. I just shampooed the carpets yesterday and used the hot water from the water heaters. Still steamy hot, but not scalding. One water heater is plumbed into the next with the final one wired through the inverter to have hot water while driving. When boon docking, we run the generator in the morning to heat water, coffee, charge batteries for 2 hours and the water stays hot all day. Good Luck, TomC
Thanks for all the input, it sounds, like me, know has done the math, does the LP fuel use more if left on all the time and cycles or turn it on and run for 30 to 60 minutes use and turn off. I have been to lazy so far to do it myself. I do not worry about the electric side, I on a power pole and it is not my nickel.
This is not a concern with a tankless water heater...
Quote from: lvmci on January 02, 2018, 09:52:17 PMThis is not a concern with a tankless water heater...
Speaking of, I put in a Rennai tankless heater at my house about 5 years ago. It has been *perfect* once I got it tuned up. There is a "dipswitch" that allows you to switch from Very Warm to Pretty Hot; I found the Pretty Warm to be just not hot enough, so I pulled the cover, move the switch to Pretty Hot and now it's great. The heat is very close to instant - in the time it takes to run the cool water from the tankless heater to the shower or kitchen sink, it's fully warm. It uses less than 1/10th of an amp of electric power (for printed circuit and electronic pilot) and is easy on propane. Of course, as long as there's a trickle of electric power and propane in the tank, the supply of hot water is endless.
a cpl weeks ago, i embarrassingly wrote that I didn't know where the water heater was. Well, I found it...it's in the bay next to the fresh water tank. I guess I never noticed it before.
It's electric and works great unless my wife showers before me of course!
Leaving a tank water heater on all the time will use more energy than if you only turn it on when needed.
The hotter it is, the faster it looses heat to the surrounding environment - So, if you let it cool down during periods of non use, you aren't paying for as much lost heat.
I think I would start with optimizing the insulation - then worry about turning the heater off & on. . .
We don't turn our water heater on and off in our house so why would we do that in our mobile house. It stays on 24/7 stationary or on the road.
Quote from: Tony LEE on January 03, 2018, 07:29:29 PM
We don't turn our water heater on and off in our house so why would we do that in our mobile house. It stays on 24/7 stationary or on the road.
same here, mine is an all electric coach with a 36 hr battery inverter capability to maintain refrigeration, entertainment and microwave.
in extreme climate heat or AC my electric consumption is $160.00 worst case on the pole.
i can sustain my needs in 3-4 hrs gen time in National parks with generator restrictions for weeks. for example, i do Death Valley in October/November or the Tetons/Yosemite in May.
and I do July in AZ on the pole.
there is no free lunch.
We turn on the propane water heater when we leave home, and leave it on for the duration of the trip. I have turned it off some times, and forget to turn it back on, frustrating. The little bit of propane we would save, if any, is not worth the trouble.
JC
If your primary mode is boondocking with an electric water heater, then less energy is used turning the heater on and off as needed. Less energy is used since the water does not keep it constantly at temperature.
If you are on the pole or running gas heater, it's less of a concern. If you constantly battle house batteries from running down and running the genset the fewest hours to keep the house bank full, then this tactic works.
Agreed if you're boondocking turn the electric water heater off. But we are fulltimers. We'd never turn our water heater off...we need hot water every day for showers, dish washing and laundry.
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