An energy audit should be undertaken before energy-improvement measures are implemented. The audit evaluates the building’s current thermal performance and identifies any deficiencies in the building envelope or mechanical systems. Local utilities may offer simple audits at no cost or more in-depth audits for a reasonable fee.

The energy audit measures the R-value of various components of the building envelope including walls, ceilings, floors, doors, windows, and skylights. The R-value is a construction industry standard of measurement of resistance to thermal transfer, commonly known as heat loss; the higher the number, the better the resistance is to heat loss. The audit also includes inspection of the building envelope to identify areas of air infiltration. Tools such as a blower door test blower door test or infrared thermography may be used to identify specific areas of infiltration, lack of insulation or thermal bridging. The type and age of mechanical systems and major appliances are also recorded.

The results of the energy audit will identify current deficiencies in the building and will help you select the most cost-effective remedial measures, such as added insulation, caulking, lighting improvements, and repair or replacement of mechanical systems or major appliances. Once you diagnose where problems exist you can determine which improvements will be the most cost effective and will provide the maximum comfort and energy savings.

Find more information about home energy audits at Energy Star or learn how to perform a simple energy audit yourself.