Tankless electric water heater recommendations?

[claudrea]

Hi! I'm looking for a tankless electric water heater. Any recommendations?

 

[Rucker]

Curious why electric-maybe you have a huuuuuge solar array?

 

[Jolly Roger bus 223]

just a thought?
for almost anything electric?
the higher the voltage the more energy efficient the appliances are.
so a 240v instantaneous water heater will be cheaper to use in the long run but what would the upfront cost be to run a 240v setup?
why not propane fired with a 12v ignitor? or something similar?

 

[claudrea]

We are planning on running all appliances on solar energy! We don't feel comfortable having propane on board!

 

[ABBus]

At home, we had an ecosmart 18. 18kW. Just enough for running a shower comfortably. I can't imagine running that thing from solar power.

 

[Morgan-SKO]

@OP did you ever find one you liked? I'm in the same boat, don't want to have any propane on board for a bunch of reasons and want to do hot water on demand via electricity. Would love to hear if you found something suitable

 

[kuja]

@OP did you ever find one you liked? I'm in the same boat, don't want to have any propane on board for a bunch of reasons and want to do hot water on demand via electricity. Would love to hear if you found something suitable

Looking to follow-up on this question too!

Anyone else have suggestions?

 

[Rucker]

I did a little research. If you limit yourself to 110 volts there is no solution. 110v just does not provide enough flow for more than washing your hands, literally. About a half a gallon per minute (GPM). Maybe you can wash one hand and get away with that.

220v options are many; all require massive current, starting at around 30 amps for a minimal flow of ~2 GPM. By comparison, my propane system pumps 2.64 GPM. Propane does a fantastic job at adding calories of heat.

So heating water quickly falls into two camps, 1)those who use propane, and 2) those who have massive solar systems, inverters and battery banks. I'm guessing ten grand plus systems. From the lack of response to your question I suspect there are few in the second category.

I'm reminded of many posts in this forum that end with 'you may want to rethink your constraints, or what it means to live the skoolie life'. Hope this helps.

 

[Willie_McCoy]

I did a little research. If you limit yourself to 110 volts there is no solution. 110v just does not provide enough flow for more than washing your hands, literally. About a half a gallon per minute (GPM). Maybe you can wash one hand and get away with that.

220v options are many; all require massive current, starting at around 30 amps for a minimal flow of ~2 GPM. By comparison, my propane system pumps 2.64 GPM. Propane does a fantastic job at adding calories of heat.

This is the answer right here. There are very few viable options for electric tankless water heaters in a residential application where the available power is effectively limitless. I have been in the plumbing and heating industry for over 20 years now and have never installed an electric tankless heater outside of point-of-use 110v units for handsinks that are rated for 0.5gpm or less. They just aren't a viable option when flowrates rise.

That being said, and given your absolute refusal to use LP, I still think there may be ways to heat water with electricity but they will require some ingenuity, creativeness, and a storage tank.

Rucker, what are you using for a tankless LP heater?

 

[Rucker]

Rucker, what are you using for a tankless LP heater?

Camplux 10L 2.64 GPM High Capacity Propane Tankless Water Heater, White. Cost about $280, runs on 110 (very low amp usage). I did not want the double D battery version of this heater.

I've picked up a recirculating pump, and have to decide whether to put it in. I might wait and see how it works first. The thinking is I can add hot water capacity with a holding tank if needed, to keep the instant heater from cycling on and off.

I have a propane tank enclosure, vented, and just run the water heater off the barbecue-style tank.

I mounted the heater inside and it vents through one of the little slide windows in the shuttle bus. Open the window and pop out the vent, it's ready to go. When done, stow the vent, close the window. No wall or roof penetrations.

I was going to run it on a separate, 500W inverter so I could turn off the 2Kwatt inverter for eco-mode, but I'm still figuring out how auto-transfer of shore power and battery will work.

 

[rossvtaylor]

And, keep in mind that the mention Rucker made of a 220/240 volt heater drawing 30 amps (minimum) was at that voltage...at 12 volts, that's 550 amps (plus the inverter conversion loss). With a typical 400 ah battery bank, even if you could draw at that rate without melting things, it wouldn't be long before you would crush your batteries to the max dod.

 

[Rivetboy]

We are planning on running all appliances on solar energy! We don't feel comfortable having propane on board!

Well! My advice to you is to learn how to do load calculations. This required skillset will teach you that hot water from electricity does not come from Unicorn farts. If you want a a reasonable sized water heater that provides 2.5 GPM of heated water
it will need (X) watts.That is the minimum in solar array for your purpose of heated water. Now add in the load of the water pump and you have hot water when the sun shines Now, figure out how big of a battery bank you will need to provide that for multiple cloudy days and nightime.
Your system fails quickly when there is no sun and batteries are depleted = no hot water. By the way, what are you planning to cook with? (another huge electrcal load) What are you going to do when the batteries die?
Back up candles?
Fire up that Unicorn fart generator...