General Query about temporary, portable/at point, electric water heaters

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New Member
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Ohio, USA
This is a bit long, apologies, but getting some unfriendly, unhelpful replies elsewhere, and just looking for solid suggestions.

Recently bought a house that will be a long term renovation. Currently there's no working hot water tank; previous owner said it cracked and drained. It's still sitting there, but the utility room was a poorly built addition, and has some water damage to the floor and other structural issues that need resolved before we have someone out to put a new tank in.

I'm looking for a temporary solution to heat water for baths, without a hot water tank.

I read about immersion rod heaters; they look terrifying and i have nightmares about electrocuting myself, which might just be my non-plumbing expertise getting the best of me. I also read about point of use/on demand water heaters, some that go under the sink. Would something like that suffice? Is there a better solution? I realize they would not have a fast output, but would they be capable over a period of time to add enough hot water to a tub of cold to make it bearably warm enough to bathe?

Looking for something in the $300 or (preferably) less solution range, suitable for use 2-3x a week, over a 3-4 month period.

Needs to be electric based; gas isn't turned on and will need to have work on the lines done before we can.

The electricity usage/outlet availability is also a concern; i'm not an electrician capable of installing high output outlets. Also hate to spend an excessive amount on this, as opposed to repairs, so would any solution be able to be plugged into a regular electric outlet, or am i looking at additional electric work to make anything safe/work? The 120 volt, 20 gallon hot water tanks someone suggested have additional requirements for the electricity- are any made smaller or suitable for regular electric outlets?

Other things to consider: Bathtub faucet doesn't work, so i'm pulling water from the bathroom sink to fill the tub (and the kitchen sink to pull water to boil). Any kind of solution that plugs into an existing faucet would need to be okay with a bathroom or kitchen sink faucet as the source. Bathroom is on the 3rd floor, no windows, so garden hose/outdoor connection not an option.

This house is very much a labour of love. Again, i am not a plumber (or an electrician), not pretending to be one, or implying plumbing is something any DIY non-pro can just watch a youtube video to learn. This is all new to me, and i'm honestly just asking if there's anything that might work. We're using pros for the non-basic stuff not in our wheelhouse, but the fiscal expenses are going to mean we repair it in stages, and i just need a temporary solution for a couple months, while i do what I can from here. Any suggestions, input, etc would be greatly appreciated.

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In the Trades
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Berkeley, CA
A little hopefully informative math:

A regular receptacle is rated for 15A at 120V, or 1800W. [If a load is going to run continuously, meaning more than 3 hours, it needs to be limited to 80% of that.] A Watt is 3.41 BTU/hr, so 1800W = 6138 BTU/hr = 102 BTU/min. A BTU is defined as the amount of heat required to raise one pound of water 1 degree Fahrenheit.

So say you want 100F water for showering or bathing, and your incoming water is 50F. That means you need to raise the water temperature 50F, and your 1800W heater can do that at 2 lbs of water / min. A gallon of water weighs 8.34 pounds, so the 1800W heater can heat about 0.25 gpm. While a typical shower is 2 gpm.

In other words, it takes a lot of energy to heat water. If you are limited to using one 120V/15A circuit, you need a tank. I don't know what's commercially available, but there's no reason that a 20 gallon or 30 gallon tank couldn't be heated (very slowly) by a 120V/15A circuit, and provide enough hot water 2-3 times/week for a short shower or small bath.

Cheers, Wayne
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