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rogerddd's avatar
rogerddd
Explorer
Jan 05, 2018

On-demand water heaters

On-demand water heaters – do they work?

We have a new Thor brand class C Motorhome with an tankless Girard Brand RV water heater. In the shower the water will temporarily turn warm after the hot water faucet is on and run for a while, but it cycles between warm and cold, so we end up showering with mostly cold water. Both the manufacturer and RV repair facility tell us the same thing: run the faucet until warm water flows, then reduce the flow to sustain the warm temperature. When hooked up to city water, this almost works but with dry camping it does not work well and takes too much water to sustain even water occasionally warm. Washing dishes offers a similar experience. Anyone have good success with tankless water heater in their motorhome? Is so, how did you get it work?

15 Replies

  • For previous posts search this Forum for `tankless' or `on demand', etc.
    Unless there has been a vast improvement in the design the only time they would work well is if one is connected to campground water and the gray tank valve is open. That's my $.03 adjusted for inflation.
  • The problem with the on demand water heaters is that they only work to capacity when you have full hook ups. There just is no free lunch here. Without water and electric you will quickly deplete you fresh water supply {and dent your battery bank} as that 6 amp+ an hour water pump runs and runs while you await a steady stream of hot water.

    At the same time, you are quickly filling your gray tank which, if you have a proper sewer hook up, will necessitate frequent trips out to the dump hose to open the valve and drain the tank. I doubt that these systems use significantly more propane {if any} than conventional water heaters but not having the electric option ultimately costs more over time {there are lots of CG's and RV Parks that provide electric even absent full hook ups. Additionally these are usually cheaper than the full hook up park down the road}.

    Off the grid, the performance issues noted by the OP seem to be common. On demand systems work well in residential applications but unless you always have full hookups they have their limitations in the RV world.

    My bride and I have no problem getting nearly instant hot water from our 6 gallon propane/electric water heater. It comes out of the galley faucet steaming hot in mere seconds {the water heater is located directly beneath the galley sink}. We can both take short but very hot showers back to back without exhausting our hot water.

    As always... Opinions and YMMV.

    :C
  • Well this is discouraging! I keep hoping to hear some good reports about these but it doesn't seem to happen.
    Good luck and welcome to the forum.

    Scott

    (PS, btw, your not allowed to post the same thing in multiple threads.)
  • Perhaps this will help. I'm not familiar with the brand you mentioned.
    https://www.youtube.com/watch?v=eE89B4zQoKc

    Here's another
    https://www.youtube.com/watch?v=1-6YQUuVyqM

    And yet another
    https://www.youtube.com/watch?v=cZ5i8FzU4UE
  • just my .02 worth they were never made for rv,s and most of them don,t work great in a house ,you gotta run a lot a water down the drain, for it to work correctly..