As one of the leading Energy Auditor, being realistic, you should realize that depending on how old your home is, you might save a lot of money after a while, but if you follow the advice, you will save a lot over time. Many variables affect the cost of a home energy evaluation, making it challenging to assign an exact figure. Ultimately, the price is determined by the difficulty of the work and the number of hours a professional works on your house. The following variables will affect the amount of time and level of difficulty. How hard it is to complete a home energy audit depends partly on how big your house is. In addition to the fundamental square footage, other essential factors are the quantity of windows, light fixtures, HVAC units, and other equipment.