Energy Calculator The last big question is "What in my house accounts for the energy being used?" The energy calculator lists many household systems and appliances and estimates of their monthly KWH usage. Check the appliances that apply to your home and change any of the default values in the Avg. Monthly kWh column as necessary. Also check out our Energy House to learn how to save on your energy usages. It is very important to remember, however, that these numbers are only estimates, and due to the wide range of conditions which vary from home to home it is very difficult to get a good estimate which is accurate for everyone. To determine a more accurate estimate, use the guided worksheet (PDF format).Click here for the Energy Calculator