Insulating drafty electrical switch box

[zzvyb6]

If thats a full basement or a crawl space, go look there to see if air is coming in (or going out) via the foundation plate. Since you say frost forms on the wallplate cover, I'd presume that humid interior air is leaving at that point. Many times, insulation is poorly installed there. And, air is probably following the wiring through the studs. Also check the attic. Air under pressure can find its way quite a distance. I'd send a can of foam along the outside of the electrical box (from the inside wall) on all sides. You can find extra-wide cover plates if you have to knock out a little drywall to get the job done. Also check the bottom of the siding on the outside where it meets the cement block. This is a notorious place for winf to enter. I have no problem with stuffing the box with glass insulation.

Check with your local fire department. They may have a F.L.I.R. gun or camera which can be used to locate the cold air chute. Forward Looking Infra-Red cameras are used to find fire in walls and bodies in burning homes. Some Utility companies will bring one when they come out to sell you inulation packages. The heat patterns may be able to tell you where the problem actually is.

 

[JDgreen227]

Cut power and drill a 1/4" hole in the back of the box to stick the straw through. Might also need a hole in the top/bottom depending on how the cavity is laid out.

Aaron Z

I


I like that idea...little mess and no damage and the wall is 2X4...another post asked about possible air infiltration from above or below, very good point. The interior wall area above the switch box is reasonably warm while the wall area below the switch box feels about 10 degrees colder than the upper area. The construction was a do-it-yourself project as was the insulation and I could have sworn we insulated fully inclusive of tucking a strip of fiberglass behind the boxes. I did all the caulking on the sills of the entire basement but because the basement walls and ceilings are studded, insulated, and drywalled it would a huge PIB trying to find a source of infiltration from underneath. Thanks to all, you have given me a lot of advice !!!

 

[Dutch445]

when you describe the location of the switchbox, is it on the same wall as that window? if so, could it be directly above that
black wire looking thing coming out of the siding near the bottom of the siding?
i would almost think that for now, get the foam insulator for under the cover,
and in summer start taking things apart, if you have that much air blowing thru,
then i doubt it has to do with the insulation around the box, but that
entire bay may have been missed, and/or there were some other areas that
weren't sealed well, maybe around the window. air could follow behind the
siding to a sheathing seam etc. but it sounds like a pretty substantial leak
on that side of the house.
the good thing, it's fairly easy to remove siding, and between the corner and window
is a piece of cake, you could do that this summer and see how everything is taped up
and how the housewrap looks

 

[JDgreen227]

when you describe the location of the switchbox, is it on the same wall as that window? if so, could it be directly above that
black wire looking thing coming out of the siding near the bottom of the siding?
i would almost think that for now, get the foam insulator for under the cover,
and in summer start taking things apart, if you have that much air blowing thru,
then i doubt it has to do with the insulation around the box, but that
entire bay may have been missed, and/or there were some other areas that
weren't sealed well, maybe around the window. air could follow behind the
siding to a sheathing seam etc. but it sounds like a pretty substantial leak
on that side of the house.
the good thing, it's fairly easy to remove siding, and between the corner and window
is a piece of cake, you could do that this summer and see how everything is taped up
and how the housewrap looks

Good point, and the switch box is located on same wall as the window and basically behind the inside corner trim of the siding. The black wire is a 10 year old cable that was run in from a dish at one time and has been heavily caulked. Although the sill of the concrete block wall has also been caulked and it has been fully insulated both in basement as well as above ground, the block foundation on the window side of the picture dates from 1951 (!!!!) and there may be cracks I am unaware of.

 

[Gunny]

Be carefull with that spray foam, I blew out a door jamb first time I used it.

Yessir, make sure you use the minimal expansion foam, I've saw one home where they had this same problem and used the regular foam, really blew it in there and popped the drywall away from the nails!

 

[JimRB]

If you do not have house wrap on the outside one might argue the house is not properly insulated. One problem with fiberglass insulation is air infiltration. Second is some installers just wad the stuff up behind electrical romex, water pipes or other obstacles instead of making slits to encapsulate the obstacles. But you still have air infiltration issues. That is why some folks do the hybrid spray foam first to stop air infiltration and then fiberglass. My house has blown in cellulose that is not supposed to have air infiltration problems like fiberglass but I suspect the cellulose insulation has sagged in some area that I cannot see. I did not know about the house wrap and failed to do it. It will be done if/when my siding needs to be replaced. We did caulk all bottom and top plate penetrations but lots more air sneaks in behind/around the outside plywood and foam board.

By the way I would have made a few 1/4" holes around the electrical box, inserted the low expanding foam straw and squirted foam around the box. The little holes would get sealed back up by the foam. I would also have done a squirt around where the Romex comes into the box and any other holes in the box. Same as what others have suggested. The bigger issue is if you see that much of a breeze via the electrical box you may very well have an insulation system that is not working well at all.

I keep saying I want to get an infrared thermometer to measure the house either in the dead of winter or just after sunset on a 100 degree day to see where the house is leaking heat or cool. The fancy infrared cameras would be a neat gadget but they are expensive.

 

[JDgreen227]

Original house was 2X4 construction with ZERO wall insulation and about 6" of rock wool in the attic. Back about 1993 I removed the weathered cedar siding and then the sheathing on the walls, rewired the entire house, added wall insulation then used 3/4" plywood sheathing to replace the original 1X6 boards. In the attic I spent a lot of time removing and disposing of the rock wool as there was no vapor barrier, then I added first R-23 fiberglass with a vapor barrier and covered that with R-16 unfaced batts. Made a HUGE difference in the heating bills. When I added on back in 2002 I wanted to use 2X6 studs but my ex-wife's brother said it would take a long time to get back the added cost of the thicker studs and insulation and interior window trim...and my ex sided with him. No, we did not use housewrap either. DARN.