Heating and cooling account for 50-70% of the energy consumed in the average American home. Heating water accounts for another 20%. A poorly insulated home loses much of this energy, causing drafty rooms and high energy bills. This fact sheet discusses how to determine if your home needs more insulation, the additional thermal resistance (called R-value) you would need, and what kind of insulation you should buy. It describes options for installing insulation, including do-it-yourself installation, and selecting a professional. A list of agencies and organizations providing more information about energy conservation and nine references are given. (YP)