Install foam gaskets. Install foam gaskets behind outlet and switch covers on exterior walls.
Fireplace damper. Keep your fireplace damper tightly closed when not in use. A chimney is designed for smoke to escape, therefore, until you close it, warm air will escape 24 hours a day.
Seal pipes through walls. Where pipes or wires come through a wall, floor, or ceiling, seal the hole around them using either caulk or low-expansion foam.
Close vent cap dampers completely. Check your exterior dryer and bath fan vent caps to ensure that the damper closes completely when not in use.
Look for dirty spots. Dirty spots in your insulation or on your carpet and ceiling paint often indicate holes or cracks where air leaks in and out of your home. These joints can be sealed with caulk or low-expansion foam.
Check your weather stripping: Check the weather stripping around your doors and windows to ensure that it is tight and continuous.
Install storm windows. Install storm windows over single pane windows or consider replacing them with more efficient windows, such as double-pane.