Scott, I took the home energy class last fall in South Bend, Indiana. It was an awsome class to take. They instructor even emailed us his presentation that he used for the class. On the second day we went out to a home and went thru it with the instructor.
Basically they have a program which is free to have but cost $20 to have them upload and run all the calculations.
Following the software you input size of windows what direction the house faces, age of appliances. insulation in the home and so on.
Using the zip code of the address the software knows what the local utility companies are charging for gas and electric.
Within 24 hours they will email backa report that list how much money can be saved. If the customer follows what is recommend in the report. This might be instlling new furnace or hot water heater or adding insulation. or new windows.
Theres alot more to it but if there is a class given by them I strongly recommend taking it.