Find a power outlet that is on an outside wall of your home. Unscrew the cover on the plug outlet and feel the air drafting from outside to the inside of your home. In the picture below this outlet is in a bedroom where the other side of this wall is our driveway. It is a chilly spring day today and the cold air can be felt pouring from around the outlet.
Run to your local hardware store and pick up some packs of Outlet Gaskets. (They are usually by the switch plate covers). They come in all sizes and for both plug outlets and light switches and are usually less than two dollars a pack.
You usually have to pop out the perforated sections where the plugs, switches and screws go. Then place it over the plugs so it is tight fitting:
Replace Plug cover and screw into place as usual.
You now have a much more energy efficient home and all it took was some loose change and a few minutes of your time! Easy Peazy!