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Community and Q&A

Water heater insulation

Chris Johnston | Posted in Energy Efficiency and Durability on

Hi, I have a 50-gallon A. O. Smith electric water heater I want to insulate. What is the best way to do this? Should I buy a blanket? Should I build a rigid foam box around it, and if so what R-value? Any fire concerns in insulating? Any advice appreciated! It is in a conditioned basement.

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  1. David Meiland | | #1

    A rigid foam box sounds like a lot of work and it'll make it hard to replace the heater when the time comes. A blanket is easy, but energy auditors I talk to who do a lot of REM modeling don't seem to think they pay back, unless your heater is in an unheated space. IMO the best thing to do is let it wear out and then replace it with a heater that's already well-insulated. You can get a .95 energy factor from at least a couple of the manufacturers, if you're installing a 50-gallon standard height tank. I would certainly insulate the piping.

  2. GBA Editor
    Martin Holladay | | #2

    I don't know how old your water heater is, or the R-value of the existing insulation that came with the water heater, so I'm not going to comment on cost-effectiveness. But if you want to install additional insulation, the easiest way is to buy one of those blanket kits. Be sure to provide access to the control knob that adjusts the water temperature.

    As David points out, it's also important to install insulation on your hot-water pipes, especially the pipes nearest the water heater.

  3. Curtis Dean | | #3

    Be sure to check with your local utility. Most of us give customers a free water heater blanket and pipe insulation if they agree to install it. When it's free, there's no worry about cost effectiveness.

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