By using our knowledge of the three methods of transferring heat, we can see how to save on our heating and cooling energy bills.

One way that heat can escape from your house is by conduction through the walls, ceilings, and windows. Most walls and ceilings contain material to stop this heat conduction called insulation. There are many types of insulation, depending on the location in the house and the degree of insulation that is desired. One popular measure of the effectiveness of insulation is called the "R" factor. The R factor is a measure of the resistance of the insulation to the transfer of heat. The higher the R factor, the more resistance, and the less heat that is transferred. The materials and labor to install insulation cost money, so depending on the size and location of the house, there is an R factor that is the most cost efficient. Most older homes were built when the cost of energy was lower and the insulation was more expensive for the same R factor rating. Therefore, it may save you both energy and money to invest in more insulation in your walls and ceilings.

The same concept of insulation applies to windows. Typically, the "insulation" that is used is air, since regular insulation is a bit hard to see through. The air is trapped between two panes of glass. These double paned insulated windows significantly decrease the loss of heat through the windows.

The main fluid available to transfer heat by convection in your home is air. Air can come in and out of your home in many different places: cracks around your windows, cracks under the doors, places where wires or pipes come into the house, and even from the electrical outlets. There is an amazing number of different products available to keep this air flow from occurring including: strip insulation for around windows; door stops for under door openings; caulking for around windows, pipes, and wires; and small pieces of insulation that fit behind your electrical outlet plates. Often you can find the places that need to be insulated by just placing your hand in front of the crack or electrical outlet. If you feel a cold draft during the winter, for example, you probably could save energy and money by stopping this air flow.

No matter what you do, some heat energy will radiate away from your house on a cold night. The lower the outside temperature of your house, the less energy that will be radiated. Therefore, the insulation you use to prevent conduction will also cut down on the losses from radiation.

The most obvious way to save energy and heat by using your understanding of radiation heat transfer is to close your drapes at night, and open them during the day. This will allow the sunlight to enter and heat the house during the day, and keep the warm insides of your house from radiating heat away at night. Of course, the drapes also provide insulation and prevent heat loss from conduction.