On Demand Water Heater

[jerseyboy]

I've been reading about on demand water heaters and was thinking about installing one
in my boat. Has anyone done this before and are they a good fit?

[SEVEN]

If you are out you will need to run your generator each time you want hot water. Also a big pull on power each time you turn on the faucet.

[Pascal]

You may also have to add a second geneearor and extra powercord. I looked into it, these things use a ton of power

[Stripes]

I was always curious about how it'd be on a boat myself... They're awesome in commercial & residential applications!

[Toolsntoys]

I have been thinking of adding a small couple gallon water heater in the galley basement that would give almost instant hot water for the galley sink.

[jerseyboy]

I've read they are very popular in RV's and most are plug in units or a larger 7 gal one is hard wired.
All the ones I've seen are 110/120v and require just a 20amp breaker. Since they're
on demand the only power you'll draw is when they're in use.
Just thinking. Maybe someone who has one will respond.

[Photolomy]

I am not sure if the OP is talking about a small (point of use) water heater, in which case electric will work, but there is still a delay to heat the water, or a tankless (on demand) water heater, in which case, the RV models run off propane, since you generally don't have the kind of service or wiring to handle the amount of electricity a tankless water heater requires.

I wouldn't mind a small point of use water heater at the galley sink, since it takes a while for the hot water to get there from the engine room, and waste a lot of water (which matters if you are away from the dock).

[Scarlett]

Check out how many degrees above the cold water temp they will rise the water. The small ones only add about 20 degrees if I remember correctly, so if you have 65 degree water it will only be heated to 85 degrees. It tales a gas unit to heat it higher. John

[jerseyboy]

Check out how many degrees above the cold water temp they will rise the water. The small ones only add about 20 degrees if I remember correctly, so if you have 65 degree water it will only be heated to 85 degrees. It tales a gas unit to heat it higher. John

Good point. I can see this will take a little more research on my end. A 20 degree rise sure isn't much
if that's the case.

[jim rosenthal]

Do you mean at the dock, or when you are running the boat? The best way to heat water when you are running the boat is to have a coolant loop from one of the engines to the water heater. You get HOT water, and for free. You can also use a coolant loop from the genset to heat water, so you have hot water at anchor. As far as the tankless systems, I think they draw too much current for use on a boat. And for the propane ones you have to add a propane locker and chimney etc.