Home efficiency can easily be improved by taking several simple measures to reduce air leaks and drafts. By improving the homes efficiency you will not only save money on energy costs, but you will also be more comfortable in your own home. Air leaks are a major contributor to heat loss during the winter and cool air loss during the summer.
Weather stripping around doors should make a good tight seal when the door is closed. This is probably one of the largest contributors to gaps and drafts and is also a very easy one to fix. Determine how big the gap is before purchasing the weather stripping, getting weather stripping that is too small will only reduce the leak, not eliminate it. Clean off all the old weather stripping and glue to make a good surface to apply the new weather stripping.
Depending on the windows in your house they may also be quite leaky. A good way to check for leaks is with a lit candle. Hold the candle near windows and move it around, watch for the flame to shift from any drafting from the window. Be sure to keep any open flame away from drapes. The caulk is usually the culprit when a window is leaky. Remove the old caulk, use caulk softener if needed. Make sure the surfaces are all clean and apply a new bead of caulk to seal up the window.
With the lit candle you may also want to check for drafts around electrical and phone wire outlets. These are areas where the wall has been compromised that air can use to infiltrate the home. You may want to pick up some electrical outlet seals, they often come in multiple packs so you can do several outlets.
Other areas to check your house for leaks would be the dyer vent and kitchen vents. Make sure these vents close off tightly when not in use. The bathroom fan could also be considered a major leak. Don't run the fan longer than is needed as it pulls quite a bit of your conditioned air right out of the house.
Sealing up leaks can greatly improve your homes efficiency. Reducing the cold air drafts in the home should enable you to lower the thermostat a couple degrees in the winter and still feel comfortable. The items needed to seal up these leaks are inexpensive and none of the projects are that difficult. With a small investment of money and an investment of some time you will make your house more comfortable as well as save money.