In the quest to stop the temperature in your home from rocking between too hot and too cold, you've no doubt changed the weatherstripping, had the AC tuned up pre-season, changed the filters, and ensured that all vents in your home were open. But there's one more thing you need to check: your electrical outlets, cable outlets, and phone jacks. These outlets often let small drafts into rooms in winter and let AC-cooled air seep out in summer. But fixing this problem is really easy.
Other Rooms' Window Into Your World
What's happening is that each outlet box has several small cracks and holes in the casing, usually in the corners where the sides of the box meet, or where the wiring for the outlet enters the box. These openings allow whatever is in the room (such as cool air) to flow into the walls, and thus into other rooms through the openings in the outlets in there.
These openings sometimes exist because the outlet boxes were poorly made or poorly installed, but they can exist on even good-quality boxes that were installed well. Age and the constant pulling and pushing the box can experience when you unplug and plug in appliances can create small openings over time.
An Entry or Escape Route for Cold and Warm Air
As a result, you can feel cold drafts wafting into the room from outlets (and even if you can't feel them yourself, you can hold a candle flame in front of the outlet and see the flame move), as well as have warm air in summer seep in. That makes the temperature in the room more volatile and makes your AC and heater work harder. That also raises your bills.
Block It Easily
The solution, though, is very simple: Install special foam insulation sheets. These are cut to fit standard outlets and light switch plates. All you do is unscrew the screws holding the plate to the wall, remove the plate, position the piece of insulation, put the plate back on top, and reinstall the screw. Look for brands that use flame-retardant foam.
These sheets will help stop drafts and seepage. A great side effect is that they might also stop odors from coming up through the outlets as well.
If the insulation doesn't seem to help, though, and nothing else seems wrong, call an AC replacement and repair company back in to double-check the unit itself. There could be a problem that wasn't spotted during the last inspection or that formed after the last inspection.