Weatherization reduces your energy bills for a long time. Some measures, such as insulating your walls or roof, for example, will continue to provide you savings for the lifetime of your house—30 years or more. Others, such as making your heating or cooling equipment more efficient, will provide savings for 10 to 15 years. On average, the value of the weatherization improvement to your house is 2.2 times greater than the cost of the improvement itself.