1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)
    Caluwe - Passion for Fire and Water ( Pellet and Wood Hydronic and Space Heating)

Hot Water Heater Insulation Blanket

Post in 'DIY and General non-hearth advice' started by Backroads, Dec 17, 2008.

Thread Status:
Not open for further replies.
  1. Backroads

    Backroads Feeling the Heat

    Joined:
    Jun 19, 2008
    Messages:
    311
    Loc:
    Richmond, RI
    Just wondering if it is worth the $35 to put a insulation blanket on my Electric water heater? I can't seem to find anyone who had done this. My basement is very drafty and I think this would be well worth it. Am I right or will I be wasting money?

    Thanks in advance guys.

    Helpful Sponsor Ads!





  2. stee6043

    stee6043 Minister of Fire

    Joined:
    Aug 22, 2008
    Messages:
    2,342
    Loc:
    West Michigan
    I think the R value of those blankets is like R3 or R5...I think it would take a while to recoup your $35 with such a low R value. But I suppose it couldn't hurt!
  3. jebatty

    jebatty Minister of Fire

    Joined:
    Jan 1, 2008
    Messages:
    4,405
    Loc:
    Northern MN
    For electric hw heaters only: skip the marketed insulation blanket and buy 6" fiberglass like that used for walls. Raise the hw heater up off the floor with 2 x 6 framing, put foil bubble insulation on floor and fiberglass on top to insulate under the hw heater. Then wrap sides and top with 6" insulation. Wrap outside and top with foil bubble insulation. Modify plumbing to install good heat traps. Insulate as much as you can all hot water pipes.

    We did above and we realized a 50% reduction in our electric use for hot water. Payback on this project, if you can do it yourself, will be about 6 months and will save big dollars over time. A very worthwhile project.
  4. Jay H

    Jay H New Member

    Joined:
    Nov 20, 2006
    Messages:
    659
    Loc:
    NJ
    Speaking of insulating hot water copper lines, I've used a bunch of those kid's "noodle" floatation toys you can find in the summer time and used as floatation aids. They are closed cell foam and generally are hollow in the middle. They also come in usually bright funky colors and are a lot cheaper than the actual insulating foam you can buy that are pretaped and all that. I simply cut them down the middle with a knife and installed them on my hot water lines. They are generally thicker than the store bought ones but for free, the price is right!

    Jay
  5. Backroads

    Backroads Feeling the Heat

    Joined:
    Jun 19, 2008
    Messages:
    311
    Loc:
    Richmond, RI
    I've already did all the lines. The local cheapo store here has the pipe insulation 6 ft lengths for .89 cents! As for the water heater, replumbing really isn't an option. Though I will keep that in mind in the summer. It's only a 40 gallon tank and every year we seem to run low on hot water faster and faster.
  6. billb3

    billb3 Minister of Fire

    Joined:
    Dec 14, 2007
    Messages:
    3,473
    Loc:
    SE Mass
    I'd be working on the drafts myself.

    Some recommend draining the tank once a year to make sure there is no sediment build up on the bottom.
  7. Backroads

    Backroads Feeling the Heat

    Joined:
    Jun 19, 2008
    Messages:
    311
    Loc:
    Richmond, RI
    As for the drafts, without boring you with all the details, all the windows were replaced last year. All 25 of them. And on the other side of the building is a garage door that is opened quite frequently. There is no heat in the basement due to me running the stove 24/7 so the temp in there is very cool, sometimes just above freezing. Mainly because of the garage door I think.
  8. billb3

    billb3 Minister of Fire

    Joined:
    Dec 14, 2007
    Messages:
    3,473
    Loc:
    SE Mass
    If that is garage under, can you box in a stall ?

    Blankets are usually recommended on (especially older) electric heaters. Payback may be sooner on yours if the basement isn't terribly wind and weather tight.
  9. struggle

    struggle Minister of Fire

    Joined:
    Oct 24, 2006
    Messages:
    727
    Loc:
    NW Iowa
    Mine looks horrible but since I covered it with attic insulation and raised it off the floor like was mentioned and put insulation under the support box under it my electric bill went down lower than it had ever been. The top of my water heater was always warm so I knew I was losing heat and also my floor was always cold so getting it off the floor helps a lot since you break the heat sink of the concrete to the bottom of the tank.
    [​IMG]
  10. Hansson

    Hansson Feeling the Heat

    Joined:
    Jul 2, 2008
    Messages:
    393
    Loc:
    Sweden,Leksand
    My heater whit extra insulation and whit no extra

    Attached Files:

  11. captaintone

    captaintone New Member

    Joined:
    Dec 30, 2008
    Messages:
    43
    Loc:
    upstate new york/orange county
    I am not to sure about electric hot water heaters, but I just had to replace my nat gas HWH that had an insulation blanket on it. My plumber told me thats the worst thing you can do to them. They are already insulated, and the outer insulation causes them to retain moisture and rust then rot away.
  12. jebatty

    jebatty Minister of Fire

    Joined:
    Jan 1, 2008
    Messages:
    4,405
    Loc:
    Northern MN
    Insulation considerations are different for a gas vs an electric HWH. Mine are electric and my comments are related only to them. I am hard pressed to find how moisture can be trapped under an electric HWH insulation blanket to rust out it out. I suppose if you had a water leak into the insulation, it would be good to dry it out. But where else would the condensation come from? The tank is hot, heat permeates the insulation. My elecric HWH has been tightly wrapped with 6" fiberglass on the top, bottom and sides, plus plastic/foil bubble wrap on the sides and top, for many years. The only loss I have suffered is the 50% reduction in my hot water electric heating bill (hot water pipes also insulated).
  13. brink

    brink New Member

    Joined:
    Dec 31, 2008
    Messages:
    64
    Loc:
    Western Central New Jersey
    What about in summer with condensation? My electric HW heater is in the basement and I was thinking of wrapping it with 6 inch batts of fiberglass insulation. then I recalled how it is covered with condensation on some of those humid summer days. Does using the 6 inch fiberglass prevent condensation as well as heat loss?
  14. gpcollen1

    gpcollen1 Minister of Fire

    Joined:
    Oct 4, 2007
    Messages:
    2,026
    Loc:
    Western CT
    Get a Heat Pump water heater to attach to that thing and then you can dehumidify for the summer months while making hot water. I have mine off right now for the winter as my basement/garage is running around 40 degrees right now.

    http://www.nyletherm.com/waterheating.htm
  15. billb3

    billb3 Minister of Fire

    Joined:
    Dec 14, 2007
    Messages:
    3,473
    Loc:
    SE Mass
    Condensation is from temperature diffrentials and humidity in the air.
    The insulation removes the temperature diffferentials.
  16. semipro

    semipro Minister of Fire

    Joined:
    Jan 12, 2009
    Messages:
    2,345
    Loc:
    SW Virginia
    Backroads,
    I've wondered the same thing. The tank is already insulated with foam so I'm not sure whether the additional fiberglass is worth the money or effort. As my water heater is in my basement I figure any heat lost is just going to heat the house anyway. Maybe your situation is similar.

    Someone's comment about raising the water heater off the floor makes a lot of sense though. Even in a heated basement there's not much use in heating the concrete under the water heater. That's conductive heat loss too, not convective, so it might be a higher rate loss.

    Seeing as there's no air in contact with the metal tank, just foam, condensation should not occur. At least, not unless the outside surface of the foam falls below the temp where condensation would occur (dewpoint?). I wouldn't worry about the rust issue, at least not on an electric heater.
  17. Jack Straw

    Jack Straw Minister of Fire

    Joined:
    Dec 22, 2008
    Messages:
    2,161
    Loc:
    Schoharie County, N Y
    What am I missing here??? If the inside is full of water why would you worry about the outside getting wet??? :question:
  18. struggle

    struggle Minister of Fire

    Joined:
    Oct 24, 2006
    Messages:
    727
    Loc:
    NW Iowa
    Me thinks it is like when a toilet tank sweats. If the hot water heater is covered with insulation then this would not occur. I have personally never seen any condensation on our tank prior to covering mine with a blanket plus.
Thread Status:
Not open for further replies.

Share This Page