The audits can cost $100 to $400, but they can lower both summer cooling bills and winter heating bills by finding leaks and other sources of wasted energy. How much you save depends on how much repairs cost, the size of the leaks found, how big your home is, and your electricity price.
Knowing whether or not you need a home energy audit—and whether it will pay off—is tricky. Amann says you should get one if you feel like you are paying too much for electricity (who doesn’t!), and she suggests talking to friends and neighbors. Some utilities are making it easier to see how your usage compares with others nearby, either as part of your bill or with online tools.
If you opt for an audit, Amann suggests using a contractor who participates in the Department of Energy’s Energy Star home performance program.
A thorough audit—more than just a walk-through of your home—will include something called a “blower door test.” A device is attached to your front door that sucks air out of your home, allowing leaks to be detected. It also establishes a baseline to test the home again after leaks are fixed to determine how effective the repairs were.
Some repairs will be clearly cost-effective, like adding insulation or closing up cracks with caulk or weather-stripping. Others might not be. Windows and central cooling and heating systems are so expensive that the savings might not justify replacing them if they are still working well.
If a new central air-conditioning system costs $5,000, including installation, and it cuts power consumption by 20 percent, it would take 18 years for it to pay off for a typical power customer. If it is time to replace the system anyway, buying the most efficient one available usually pays off more quickly.
The auditors will have tips for reducing energy use in other ways, like unplugging devices that aren’t being used or replacing inefficient appliances and lighting. They’ll recommend changes in behavior, too, such as not running appliances like dishwashers that add heat and humidity to a home during the hot part of the day.
“These are simple, common sense things but sometimes people just don’t think about it,” Amann says. “We all have our habits.”
(Jonathan Fahey can be reached at http://twitter.com/JonathanFahey.)