With so many different types of energy efficiency services available to the consumer, today, the term "energy audit" is being used in a variety of contexts that can be confusing to the average person. Hopefully, this will clear up some of the confusion.
1. What is an "energy audit?"
Depending upon who is performing it for you, it can be a variety of things. Here are common examples.
a. Diagnostic energy audits - Conducted by a Building Performance Institute trained and certified energy auditor that measures the existing conditions of the home with a variety of sophisticated tests (blower door, combustion analysis, infrared inspection, etc) and information from the occupant(s) to collect information that will be used to model the home. With the model, the certified auditor will be able to determine the amount of energy that is being wasted, diagnose specific actions to eliminate or reduce the waste, and project actual energy savings derived from the recommended actions.
b. Non-diagnostic "energy audits" - Conducted by trained data collectors will provide the occupant of the building with a "rating" or other form of statistic allowing the owner to compare the assumed energy efficiency to other homes who have received the same type of non-diagnostic rating inspection. Because the data collectors are usually not certified to perform blower door tests and other sophisticated measurements they cannot safely diagnose specific issues or recommend physical changes to the air exchange rate of the building. They will, instead, focus on behavioral issues (lowering thermostats, improving insulation levels, weather-stripping, etc) and will refer the occupant to a certified Building Analyst or equivalent for a diagnostic energy audit.
c. "Free" or inexpensive energy audits - Conducted by contractors who are selling windows, heating/cooling systems, and/or insulation or some utility companies and are generally promotional in nature. The objective is to promote energy efficiency through the use of their specific type or brand of merchandise or utility. The "audit" is similar to a non-diagnostic rating which usually will result in a recommendation for the purchase of the offerings of their company. Electric company auditors will offer rebates on electric water heaters, gas company auditors will offer rebates on gas water heaters...and so on.
2. Who should I allow to do my energy audit?
The most economical and efficient means of determining what steps to take to improve the performance of your home in regard to its efficient use of energy is to receive a diagnostic energy audit from a Building Performance Institute certified professional Building Analyst. This saves the step of paying someone to come and "rate" your home without being able to provide you with all of the information that you will require to take the necessary steps to improve your home's energy performance.
Implementing modifications to the home without the full diagnostic analysis and recommendations has resulted in numerous instances of wasted money in errant purchases, increases in energy use and serious adverse affects on the home's indoor air quality in terms of mold growth and other issues affecting health.
Anyone can perform a "rating" for you after completing the requirements of the agency that they are rating for, but first speak to a certified energy auditor since many of them include the "rating" as a free service when conducting a diagnostic energy audit.
3. Typically, what is the leading source for energy waste and higher utility bills in a residential building?
In the typical home, the costs of heating and cooling a building can be reduced from between 5% and 40% by simply reducing the amount of air that is escaping from it. Improvements in these areas are usually the least expensive and have the greatest result (or "return on investment (ROI)". Because of its effect on the indoor air quality and the sustainability of the building, however, no modifications to the building's air exchange with the outdoors should be made without a diagnostic energy audit conducted by a BPI certified energy auditor.
4. Can I stop air leakage by adding insulation?
No. Insulation over air leaks and by-passes simply acts as a filter to clean the air as it leaves your building.
Prior to adding insulation, insist that your contractor FIRST test (with a blower door), locate and seal all air leaks and by-passes BEFORE covering them with new and expensive insulation. Going back to seal the air leaks later will disturb and reduce the effects of the new insulation.
If you have additional questions please ask them in the "Comments" or you may email them to me at firstname.lastname@example.org .