This will save you some utility costs and keep moisture from condensing in your walls and attic.
It only take about 3 minutes per outlet because there is no measuring or transferring of dimensions required.
This is a fun, satisfying, no cost, energy saving project. Cutting this stuff is a little like popping bubble-wrap. It's mildly addictive. I can quit any time I want.
Step 1: Simple Tools and Material
It's made of HDPE (High Density Poly Etheline) or LDPE (Low Density Poly Etheline)
Tools: Scissors, Exacto or utility knife, Screwdriver
For safety you can turn off the circuit breakers. (So I hear.) [ Mrs. Woodenbikes calls me "Sparky"] But I digress....
Thrill-seekers can leave the circuit breakers on and stand in a bucket of water while doing the project blindfolded.
I'm kind of middle of the road on the safety spectrum.