What Is It and How Does It Work?

While a DIY home energy assessment is a good idea to familiarize yourself with your home's energy-efficiency issues, the best way to get a detailed idea of where your home is costing you money is by having a professional home energy assessment done by a qualified Energy Auditor. A comprehensive home energy audit consists of a room-by-room visual assessment, a blower door test, and a thermographic scan. Some Energy Auditors will also do a PFT air infiltration measurement, but it is not necessarily standard practice.

Why Should I Consider It?

A home energy audit is a very useful tool to determine where your money is best spent in making your house more energy efficient. By seeking advice, consultation, and investigation from a qualified professional, you will be getting the best available data regarding all of the energy-consuming components of your home. Then you can make a more informed decision regarding your next steps in reducing energy consumption in your home and lowering your energy bills.

What Are the Options?

Many Energy Auditors, utility companies, and retailers of energy-efficient equipment offer free or low-cost visual assessments. This type of assessment can be a good starting point and should include a consultation to determine your desires and to discuss findings from past energy bills; a visual inspection of your walls, windows, and doors; inspection of mechanical equipment and lighting; and identification of obvious moisture problems. This basic energy audit is very similar to what you can do on your own, although it can be good to have a trained auditor at your side, especially since many utility companies provide this service for free.

A blower door test is a very effective way to determine where your home is suffering from infiltration, or air leaking in from the outside. The blower door fits within an exterior door of your house and includes a fan that decreases the pressure inside your house by blowing air out. As the house depressurizes, air will come in through all unsealed cracks and unintended openings. While the blower door is operating, the Energy Auditor will investigate your house for leaks using either a smoke pencil or a thermographic scanner.

A thermographic scan can be done either with a blower door operating or on its own. The benefit of using thermography with the blower door is that the blower door makes the locations of infiltration even more obvious. Thermography is useful because the scanner sees light that is in the heat spectrum, so the image on the screen indicates the different temperature of each object. Cool air flowing into a warm house will show up as black on the screen, while well-sealed interior surfaces will show up in white. Thermography will also show areas of your walls that are poorly insulated, something that is very difficult to detect in a visual inspection.

The PFT air infiltration measurement technique is a different type of measurement than the thermographic scan. Although this measurement does not tell you the exact locations of infiltration, it will tell you how much infiltration is occurring over time. The PFT technique is performed with two long, thin devices that are about the size of a pencil. One of these devices emits a small amount of perfluorocarbon gas, while the other device absorbs the gas. If a high concentration of the gas is absorbed, than the building is not leaking much air. However, if a lower concentration of the gas is absorbed, the building is leaky.

How Much Does It Cost?

Many utility companies offer free or discounted energy audits to help their customers conserve energy. Chances are, a free audit is a visual assessment rather than a detailed technical audit, but it still may be a useful step in determining what energy-efficiency measures you can take and whether you need a more comprehensive audit. Also, some contractors and product retailers offer free audits, but in many cases these are also a way for a company to market their services. This still may be a productive inspection, becauseyou may actually need whatever products or services the company provides, but it may be best to get a second opinion.

If you can't get a reliable, low-cost visual assessment from your utility company, you should expect to pay between $150 and $300 for a basic audit from a consultant or contractor. A detailed, technical energy audit that includes a blower door test and a thermographic scan will likely range from $300 up to $1,500. As always, be sure you solicit price quotes from several Auditors, and make sure you know what you are paying for so you can accurately compare different bids.

What Else Should I Know?

Before the Energy Auditor arrives, there are a few things you should do to prepare your home and to provide the Auditor with useful information. If you have any particular trouble spots, such as interior condensation or a tangible draft, make a list before the Auditor arrives. Also, collect your energy bills for the previous year. Be prepared to answer questions about the occupation patterns in your home, such as the times your home is occupied, which rooms are used more often than others, the temperature you set your thermostat, and so on.

Where Do I Start?

Selecting a qualified Energy Auditor is very important. You can use Energy Star’s Partner Locator to find trusted Auditors in your area, but you should also use word-of-mouth to find out if any of your friends or neighbors have had an experience working with an Energy Auditor. It is always good to speak with a few different qualified consultants or contractors before narrowing it down to one. Some good questions to ask before selecting an Auditor include:

How many audits have you performed?
Do you have references that I can contact?
What is your BBB accreditation rating?
What certifications do you have? (Look for Home Energy Rating System [HERS] Certification)
What types of inspections and tests will you perform?
Will you create a report of your findings?

Where Can I Get More Information?

U.S. Department of Energy
U.S. Department of Energy Weatherization Assistance Program
Energy Star Partner Locator