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I'm considering buying a 47 gallon Rheem short electric tank water heater: PROE47 S2 RH95. I've worked out the measurements and it will fit under my front steps, about 6' above the garage floor. Currently, a 40 gal tall gas heater sits on the garage floor about 10' to the right. The space under the front steps is concrete on top of grade.

  • I would need to add additional concrete so that it's level (or build a 2x6 platform).
  • I would need to remove the short studs shown, and add a header to open the space for access.
  • I would need to make accommodations for drainage, either to outside or to the garage floor drain.

Besides being a pain to raise the empty tank 6', what red flags do you see with this plan?

The goal is to open up more garage floor space. I've considered tankless, but I want to switch from gas to electric and I've learned my 150A panel won't accommodate electric tankless.

wide shot of under stairs area close up shot of under stairs area

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  • What, specifically, is your concern? It seems that there's enough space, are you asking about that? Are you asking if there are code restrictions/requirements? Something else?
    – FreeMan
    Jan 24 at 18:47
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    That is a load bearing wall, so a structural engineer should check it out and probably make plans to replace it. That place does not seem to have any insulation, so if it gets cold outside there is a possibility of water pipes freezing and bursting.
    – crip659
    Jan 24 at 18:50
  • Very valid point, @crip659, however, OP noted the existing water heater is in this space and doesn't seem to have freezing/bursting issues, so it's likely (but not guaranteed) that the proposed space is going to be OK.
    – FreeMan
    Jan 24 at 19:05
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    About the tankless.... gas fired tankless is the way to go if you can get a flue outside. It is better than any storage based hot water system in my opinion. Everything else, you already have mentioned, will be taken care of. The drain is only for the emergency overflow? In a basement/garage, there may not need to much to consider on the need for drainage, but follow whatever the code calls for.
    – Jack
    Jan 24 at 19:44
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    Specific concern is whether the idea of putting a 40gal water tank above head level, even if strapped multiple times, is okay (for safety and other things i dont know to ask). Nothing below 45F in mild California, but I was still considering bldg a small closet for the tank. previous owners did electric that you see, I think it represents every decade
    – dabi
    Jan 24 at 21:06

4 Answers 4

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I've done almost exactly the same thing (other than it's throughly inside, being freezing climate, and the platform is not concrete, so you're ahead there.) Think I ended up with a 38 short as a 47 short could not be had for love nor money when I needed it. I put on a tank-exit tempering valve and got most of the lost capacity back by that means (run 140°F but supply at 125°F - also keeps any Legionella from standing a chance in the tank.)

Getting the awkward, heavy (yes, even without water - 149 lbs shipping weight is listed) thing in place is the worst of it. Have to figure out how you'll do that and what will do the lifting. I used a winch and slid the tank along angled boards, with the winch positioned so that the tank swung in to the platform area once it was above the wall, after which I could push it around. A fancy rolling winch mount would be nicer. You'll need a vacuum breaker valve, most likely, as there are presumably outlets below tank level, and vacuum-crushing your water heater tank is a bad thing and against code.

You should only need to remove one stud to get it to fit, (jacket diameter is listed as 29.25 inches) which limits your header requirements. Presumably you need to earthquake strap it being in California. Assuming you have room (looks like it), go ahead and throw even more insulation at it once in place. Looks like this is one that actually includes the extra blanket for that, so allow for that extra space when picking its spot.

I'd stick with concrete for leveling the platform - can't rot, easily adjusted. Consider a sheet of XPS under the tank if you have the headroom for that, in the "more insulation is better" line of thinking.

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It's electric so there's really no information about any clearances. Albeit, 2 feet on all sides is a good rule-of-thumb.

You should read through Use and Care Manual and if you have a specific concern then update your question.

One main consideration I see is page 11, section A, checkbox 5

Sufficient room to service heater

enter image description here

One thing to consider is that if the new location is further away from your kitchen and bathroom then it will take longer to get hot water at your faucets.

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Difficult to see any concern that you have not addressed. I put an electric in an attic in IL : I had to heat trace the pipes to prevent freezing, and put check valves in both lines because of the possibility of draining from the elevation. You have neither concern, my point is that mine worked fine and I would expect your plan to work.

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I see no problem. Your heater will have specification for clearances on each side, but for an electric it's probably 0".

The more modern version of electric water heating involves a heat pump, but these are larger and require air space or outside vents.

You can also shift the studs, to minimize the span, to reduce the header need. Be sure the count the double top plate as your header, you don't need to double up.

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  • I'm not sure that a doubled top plate is rated to span much more than the 14-1/2" gap between studs. Do you have any references that says that it is? If so, how far can it span?
    – FreeMan
    Jan 27 at 12:48

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