I don't know if that title is the best way to phrase the question.

It is winter(ish) now, and I swear the hot water just doesn't last as long as it does in, say, September. The water heater tank is insulated with the standard factory insulation. The house is heated, of course. But I know the concrete slab is colder now than it was a couple of months ago.

I'm wondering about building a short wood platform (pressure treated 2x4's, 3/4" plywood) to put the water heater on. But I'm not crazy about taking the time to drain the tank and move it, and cut and resolder the pipes. I mean, I certainly can, I just don't know if it will end up being worth the effort.

Any thoughts? Does anybody think the water heater is losing substantial heat through the bottom into that big concrete heatsink it's sitting on?

  • 1
    Are the pipes in your walls and attic and basement insulated? There is almost certainly heat lost through the bottom of the tank, but it pales in comparison to the heat lost due to uninsulated pipes. – longneck Dec 17 '14 at 19:24
  • I only have the hot water pipe out of the tank insulated for a couple of feet, but not insulated beyond that. The pipes are PEX (I cut all the old galvanized steel out from the basement and ran new PEX a couple of years ago), and I know PEX conducts heat (and cold) really well... – Craig Dec 17 '14 at 21:34
  • RE: the plumbing being PEX, I know I mentioned cutting and re-soldering pipes. The pressure relief vent pipe is copper, running from the water heater a couple of feet up the wall and through to the outside of the house. If I raised the water heater, I'd have to cut that and solder a coupler on. Not a big deal, really. – Craig Dec 17 '14 at 21:37
  • have you considered heat trap gooseneck piping of inlet and outlet pipe. see: greenlivingtips.com/articles/hot-water-heater-blankets.html pinterest.ca/pin/265290234276327348/?nic=1a – Peter Tarapcik Oct 23 '19 at 18:01

Probably won't make any noticeable difference.

Normally the bottom of the water tank portion is insulated if electric, and not remotely in contact with the floor if fuel-fired (there's a burner between the bottom of the tank and the floor, and a substantial amount of space taken up by the burner assembly.) I'd save the idea until you were replacing the water heater, if you want to do it.

More likely that your inlet water temperature is lower, as well as heat loss from pipes being higher. While deep well water is fairly invariant, city and other shallow-piped water systems do vary quite a bit seasonally.

  • That makes sense. It's electric, which is one of the reasons I wondered if the bottom of the tank was more or less sitting on the pan on the floor. I suppose there's some kind of framework under the tank holding it up a ways that would also allow insulation to sit in there without being totally compressed? The water is city water, and definitely comes out of the tap colder in the winter. I have the hot water (outlet) pipe (PEX) out the top of the water heater insulated for a couple of feet, but not really insulated beyond that point. – Craig Dec 17 '14 at 21:32

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