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  1. #1
    Join Date
    Feb 2011
    Location
    oregon
    Posts
    139

    insulating electrical plug boxes

    I have a finished old farm attic that has electric boxes on the ceiling. I was using a thermal temp gun and noticed at each box there is a 15 to 20 degree difference in temperature. I have sealed around the boxes but that did not do anything. I know there was insulation above the boxes before sheet rock went up so I am not sure why there is such a big difference. Does anyone have ideas how I can get more insulation around the box now that it is finished. I was thinking about drilling a hole in the box and pumping foam above it. Not sure if that is a good idea though. Any thoughts would be appreciated.

    Thanks

  2. #2
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    I wouldn't worry too much about it. They are fairly small. You could put in a lot of effort for nothing. I suppose you could repalce them with plastic electrical boxes to reduce the thermal conductivity. The most improtant thing it to get it air sealed around it.... which it sounds like you did.

  3. #3
    Join Date
    Aug 2011
    Location
    Kingston, Ontario
    Posts
    207
    I have been sealing the boxes above each lamp in our house. There are a lot of them (20). Some have as much as 1/4" gap all round, but some less! For all 20, area could be 50 sq.in. (or a 4" diam hole in ceiling!). About same for ceiling registers, so 100 sq.in. in ceiling leaks. Blower door test indicated we had 230 sq.in. of leakage area. Fixing those and a couple of windows and we are more than 1/2 way there

    I used some duct-seal putty to close the holes inside the boxes. Some had a knockout missing, so used some aluminum tape on those. Stuffed packing in gaps and covered with latex sealant.

    One problem we have and perhaps you too, is that mice are attracted to those warm spots. They make a cavity and that of course messes up the insulation. I went up in attic and fixed some of them and on some I was able to drop box and insulate from below.

  4. #4
    Join Date
    Feb 2011
    Location
    oregon
    Posts
    139
    Thanks to the thoughts. I have sealed them the best I can but was just concerned with the temp difference. Is it normal to have that kind of temp difference between the box and the finished ceilings? I was also worried that come winter time there would be condensatiomn that would form on the boxes. Any worries or thoughts on that?

  5. #5
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    I doubt the temperature difference is any worse that the surface temp of even double pane windows. I bet all you windows have a good 20F difference on a cold winter day.

  6. #6
    Join Date
    Feb 2011
    Location
    oregon
    Posts
    139
    Yea. Now that you say that I think the temp was close to the windows. Will check tonight. Thanks for another way of looking at it.

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