When you hear the word "audit," you probably immediately go into panic mode. But not every audit has to conjure up scary images of boxes full of paperwork and scowling accountants. When it comes to a warmer house and saving money on your utility bill, an energy audit can be one of the best things you’ve ever done for yourself.
Simply put, an energy audit is an in-depth inspection and analysis of your home’s structural envelope to determine where you might be wasting energy, and then to provide solutions both large and small.
The auditor will take a number of measurements along the way, and perform a variety of different heat-loss and heat-gain calculations. All of this information is then used to determine how much heat your home is losing — or, in warmer climates, how much it’s gaining — and then offer solutions about how to reduce that loss or gain in order to make the home more comfortable and also reduce energy costs.
There’s no single set procedure for how an energy audit is performed, and they can vary in scope and complexity. Typically, however, all audits address several common factors, including insulation, windows, air infiltration, heating and cooling equipment, and ventilation.
Evaluating insulation levels
One of the first and most important aspects of the energy audit is to inspect the levels of insulation that are present in all areas of the home. Auditors typically start with the attic, as that’s one of the most important heat-loss areas in the home, as well as one of the easiest areas to improve.
They’ll measure the average levels of insulation, as well as the type and condition. Also in the attic area, the auditor will note the insulation levels on knee walls and skylight shafts.
They’ll also note the amount and distribution of attic ventilation, since that plays a key role in removing moisture from the attic and also preventing ice damming. For the same reasons, auditors also pay close attention to the condition of ventilation fans, chimneys, and other sources of moisture.
After the attic, the crawlspace and basement will be checked, with the auditor looking for the same basic factors: insulation levels, proper amount of ventilation, and good moisture control. Finally, they’ll use probes to check the levels of insulation in the walls wherever possible. Some auditors also use thermal imaging cameras to look for heat loss through walls and other areas of the home.
Inspecting for air infiltration
Air infiltration is the leakage of cold outside air into the house, and heated inside air to the outside. In other words, it’s a fancy term for drafts, and it can be a significant factor in both comfort and wasted money. In fact, depending on the age and style of the home, the U.S. Department of Energy estimates that reducing air leaks can account for energy savings of 5 percent to 30 percent per year.
The auditors will look at some of the obvious areas of concern, such as window and door weatherstripping. They’ll inspect caulking around windows, doors and other penetrations through the exterior walls. They’ll often inspect flashings, intersections, vent dampers, crawlspace doors, the areas where siding overlaps the foundation, and any other areas where air can leak into or out of the house.
In more complex energy audits, a blower door test may be performed. For this test, the auditor removes the building’s front door, and replaces it with a specially sealed panel that has a blower motor in it. All of the other doors, windows, fans, and other penetrations in the home are sealed off and the blower is activated, pulling air out of the house.
This lowers the air pressure inside the house, which results in outside air being pulled in through any available gaps or cracks. The auditor then uses a smoke stick to locate those otherwise hidden air leaks.
Windows and doors are another key factor in the audit. Imagine that you have a wall insulated to R-19. The average double-pane window is less than R-2, so that’s a pretty big energy loser in the middle of the wall — even worse if it’s single-pane. As such, the auditors will pay a lot of attention to the home’s windows.
They’ll measure the size of each one, and note its frame type, glass coating, and even the thickness of the space between the panes. Skylight sizes and types are also noted.
The same is true for all of the exterior doors. Auditors will note the size and material of the doors, and whether there’s glass in them.
An inspection of the heating and cooling equipment
Finally, auditors will examine the home’s heating and cooling equipment. They’ll usually begin with an inspection of the furnace and, if there is one, any central air conditioning equipment. They’ll look at the size, general condition, types of filters being used, and location of cold-air returns. They’ll also make note of the type of thermostat being used, and what settings are available for the homeowner to make use of.
A lot of attention will be paid to the duct system, because that can be a real energy loser in a lot of homes. The auditor will inspect the type of ductwork being used, the way it’s installed, the condition of the joints, and the level of insulation. Ductwork in the attic, crawlspace and basement will all be inspected.
Tying it all together
All of this crawling and measuring and calculating doesn’t mean much until the auditor pulls all the information together into some conclusions that you can understand and implement, and that’s a big part of his job.
The auditor will put together a written set of recommendations, covering everything from increasing insulation levels and replacing old single-pane windows, to the little things like caulking air leaks or upgrading your thermostat.
Typically, the more expensive components of the package, such as replacing windows or changing out a heating system, will be accompanied by projected payback periods to help you with the financial decision-making.
To find an energy auditor in your area, start by contacting your local utility company. Some utility companies have auditors on staff, or else they can direct you to reputable local companies who do audits. You can also do an Internet search under "energy audits, (your city)."