Insulating electrical outlets

Last Updated on November 24, 2018 by Dave Farquhar

Insulating electrical outlets and light switches is a cheap way to reduce your energy usage. I insulated mine in 2004 and it’s a quick, easy project to make your house more energy efficient that will pay off for years to come.

Insulating electrical outlets
I installed this foam gasket to insulate this light switch in 2004.

Where to buy supplies for insulating electrical outlets

I was able to insulate my 3-bedroom house with three packages of foam gaskets made for the purpose, which sell for around $2 per package. These are a standard item at hardware stores. I found some at Big Lots, a closeout store, but their price wasn’t a bargain. They’re generally cheaper at the big-box home improvement stores or a hardware store.

The idea is pretty sound. Electrical boxes don’t leave much room for insulation. That makes outlets and switches a great place for warm air and cold air to escape through the empty space. The uninsulated outlets on your outside walls probably isn’t quite as bad as keeping a window cracked year round but the principle is the same. Stick a piece of insulated foam behind the outlet cover, and you’ve created an air seal and reduced the amount of space your inside air has to escape. The foam insert also has a higher R value than your cover plate or switch plate.

In the winter months, you may be able to feel a slight draft next to electrical outlets on your outer walls from warm air escaping and cold air coming in to replace it. The foam inserts make that draft less noticeable.

Installing the inserts

Installing the foam inserts is super-simple. Turn off the power to the room at the breaker box. Remove the screw holding the wall plate. The package contains inserts for standard light switches, standard outlets, and a third that matches GFCI outlets and decora switches. Punch out the knockout, then position the insert on the outlet or switch. Then put the wall plate back on and screw it back in.

For an added degree of energy savings, plug a child safety insert into any unused outlets, or replace the cover plate with a child safety cover plate. Also, if you notice a gap between the electrical box and the wall, you could spray some spray foam into that gap to add some more insulation. I didn’t bother. I didn’t have much of a gap, and spray foam gets pretty messy.

Turn the power back on in the room, then move on to the next room. That’s it. The hardest part is keeping track of those screws so you don’t lose any in the process. Insulating a room only takes a few minutes.

If you happen to find a loose outlet while you’re insulating a room, here’s advice on dealing with loose outlets. If your plates got latex paint on them, here’s how to clean off latex paint without replacing the plate.

Insulating electrical outlets on Interior walls vs exterior walls

You get more benefit from insulating electrical outlets on exterior walls than on interior walls, since wall boxes on exterior walls are exposed to the elements while wall boxes on interior walls are only exposed to the next room. Still, installing gaskets on your interior walls does reduce the chimney effect, which allows warm air to escape through the walls into your attic.

Insulating ceiling boxes

To really go the extra mile, you can take down the light fixture, cut a hole in one of the gaskets for the wires, then cut a slot so you can push the wires into the hole, and place the gasket up against the ceiling box. You may need to put a little bit of caulk on the edge of the gasket to hold it in place. Then replace the light fixture to insulate your ceiling box. Most light fixtures have fiberglass batting in them for insulation, but a gasket will provide an air seal and a little extra R value.

Taking down light fixtures is considerably more time consuming and presumably less beneficial, assuming the fiberglass batting is actually present in the fixture. But it can reduce the amount of warm air that can escape the room into the attic. If you’re comfortable replacing a ceiling light fixture, you can probably do this too.

More energy saving ideas

I’ve done a number of other things to help make my house more energy efficient over the years. Most are pretty inexpensive. I installed thermal blinds and thermal curtains. Then I insulated my hot water pipes. Of course I also use LED bulbs.

My electric usage dropped 19 percent in 2011, so these things work.

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4 thoughts on “Insulating electrical outlets

  • March 21, 2004 at 9:51 pm

    You can also blow insulation into the stud cavities; If it’s done right, it doesn’t leave any gaps. Usually it has to be done by professional installers, but sometimes you can get access from the attic and dump in bags of loose (flame retardant!) insulation.

    Of course, being more expensive, It might not pay.

    Glad to see you back; hope you’re feeling better.

    You and I are but earth.

    • March 21, 2004 at 10:26 pm

      Blowing insulation would be a bit difficult in this house, with where some of the outlets are placed. And it’s definitely beyond both my skill set and ambition.

      Thanks for the welcome back. My doctor did OMT on my neck on Monday and it helped a ton. Then I promptly got sick–nothing to do with the doctor, someone from church shared his cold with me. That was nice of him.

      Now I’ve got stuff hurting that I didn’t know was hurting, but it’s comparatively minor. I can concentrate now.

    • March 22, 2004 at 7:30 am

      Hi Dave,

      Depending on how old your house is, insulating the outlets on the inside of exterior walls can also be a good idea.

      Our house was built in 1917 and has NO insulation (other than the properties of the brick, plaster and lathing). Insulating the outlets with foam inserts made a detectable difference when "feeling" the air around the outlet.

      Interestingly, "This Old House" magazine recommends against using blown insulation if your house has active wiring of the “knob and tube" type. Our house still does for a few circuits and it is in excellent condition (based on our inspection during some remodeling where we have seen large sections of it).

      Good luck with your home!

      – Bruce

  • March 22, 2004 at 9:15 pm

    I did the same (70-yr old house) and it probably made some small difference. But replacing the old double hung windows made far bigger difference–for far bigger $$.

    IMHO the answer to most of these things is return on your investment. Generally the only way you stand a chance to break even is to stick with the cheap improvements. There’s lots of exotic expensive stuff out there with no hope of payback.

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