When we build our RV we decided to go all-electric, meaning no propane. Why? Well, to be honest, safety. We just did not feel comfortable with the thought of propane on board so we looked for other alternatives and we ended up with a 120V, 2.6 gallons all-electric water heater.

YouTube Video of this Water Heater

Our Water Heater

Thermoflow UT10 which is a 2.6 Gallon all Electric Mini-Tank Water Heater. Its primary purpose is as a ‘booster’ under a sink but hey, we are using it for our entire RV! Well, the entire RV means one sink and one shower… yes! I said shower. More on that later.

Power Consumption

1,350W at 120V and this is really one of the main reasons why we went with this water heater in the first place. We wanted an electric water heater that ran off of 120V but stayed well under 15A.

Why We Chose This Unit

  1. Price. At under $130 it’s one of those items where if it does break, it won’t break the bank.
  2. As mentioned above, its power consumption is below 15A, meaning we can run it off of a 15A plug if need be (moochdocking).
  3. All Stainless Steel tank and (supposedly) heating element for making it maintenance free.
  4. Size. It fit nicely in the space we had.
  5. Easy installation. A couple of copper fittings to PEX pipe and a 120V plug. It really cannot get easier.

How Has It Been Performing?

We have been living in our trailer for just over 14 months now and this water heater is our only source of hot water (other than an electric kettle for tea). With it being our primary source for washing dishes and showers, it gets used almost daily (with the exception of some boondocking days). Thus far, no complaints.

We have it set to 145℉ and when we initially turn it on (we have a ON/OFF switch for it) it takes about 15 minutes to get the 2.6 gallons of water to 145℉. That is, well, hot! Its so hot that we usually end up using more cold water than hot water (to get the temperature just right) for a decent shower. Most of our showers are 5 minutes or less… it it a small tank after all.

We usually only have power to the water heater during the day, while we are at the RV. At night or while away we turn it off just to save energy however the tank does keep the water nice and warm for several hours. This varies depending on weather but I have woken up in the morning after 8 hours of sleep and still had warm water… in the 90 degree range.

Running an Electric Water Heater off of Batteries

We initially had a 12V, 800Ah, AGM Battery Bank but quickly realized that the voltage drop in the AGM’s left us… dead. We upgraded to a 12V, 400Ah, Lithium (Battle Borns) Battery Bank, and never looked back! Seriously, if you are considering running anything off batteries, go lithium!

Anyway, our water heater runs at 120V, using about 1,350W for around 15 minutes to heat up its 2.6-gallon tank. That takes about 40 amps meaning a 100Ah lithium battery would have 60Ah left.

Here is how the math works

What Would We Do Different?

Okay so it has been 14 months since we started using this water heater and well over 20 months since we purchased it and apparently Thermoflow has come out with a 4 gallon version WITH THE EXCACT SAME DIMENSIONS! I know that was not around when I ordered our 2.6 gallon. It would really be nice do have 4 gallons of hot water. Yes, it has a quick recovery rate but its not quick enough if you want to take a long shower. Maybe one day we will just change it out.


We wrapped our water heater in Reflectix just to help the water stay warm. No idea if it makes a difference but I’d do it again.

We have the water heater on its on power switch (in the bathroom with a light  so we know when its on) and it is on its own circuit breaker (15A). I highly recommend to have this setup and maybe add a second power switch by the front door so you are not wondering if its off or not every time you leave the RV.

Where to Buy?

We got this Water Heater from Amazon (this is not an affiliate link).

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Categories: Equipment