Well, it depends. That’s no surprise, right? Calculating payback on an energy audit can be complicated, much like life. My favorite response is that the energy audit pays for itself on the first day you commit significant cash to your home energy upgrade.
Often I will ask homeowners what they think is the first thing they should do to improve the energy performance of their home.
No matter how much homeowners may know about their homes, they invariably are way off base for their first choice. The physical systems of houses interact and behave in ways that are not always intuitively obvious.
The goal for a good home energy upgrade strategy is to prioritize a list of actions ranked by cost effectiveness. Some of these items should be performed sequentially to get the maximum benefit. Some items are low-cost or no-cost; these may have low or moderate impact, but because they are inexpensive, they are usually very cost effective. Some mid-priced items can yield large returns; these are the ones we want to identify and implement.
Sometimes big ticket items are necessary to get large efficiency and performance improvements, such as when the heating and air system is due for replacement.
Other big ticket items may give surprisingly small improvements despite advertisers’ and contractors’ claims. These are the items that need to be examined closely, and are often pitfalls for homeowners. An unfortunate decision on a big ticket item can lead to an unpleasant experience with the energy efficiency industry.
Professional, objective advice based on data, measurement, observation and experience is a smart investment when significant resources are about to be committed to a project.
Meanwhile, back to the checkbook. For many homes, energy bills can be decreased 10% just by occupant behavioral changes.
An excellent payback! A more comprehensive energy upgrade invoilving a number of different measures can typically yield savings of 20–30%, and sometimes more.
The cost of such a comprehensive upgrade obviously can vary greatly, depending on the size and age of the home, the nature and extent of the improvements, and whether mechanical equipment replacement is involved, among others.
Note that the payback of the energy audit is not the same as the payback of the individual improvement items, which can range from months to 20 years or more. Obviously, we expect, and generally can get, short, attractive payback times for low-and moderately priced items.
For some big ticket, capital improvement items such as heating and air conditioning, we expect them to pay for themselves over their service lifetimes.
The whole topic of payback is further complicated by the fact that many of the benefits of an energy audit are not monetary; indeed, for some people saving on utility bills is not the primary benefit.
Increased thermal comfort, enhanced indoor air quality, reduced home maintenance and increased self-reliance are just some of the other benefits of an energy audit. Fortunately, this kind of complication just sweetens the pot.
