What to look for in a high-quality energy audit

A home energy audit is a 2-to-3-hour process that uncovers issues in your home that may endanger your health or safety, waste energy, or prevent you from feeling comfortable. Energy audits are conducted by an energy auditor (or energy analyst) that has been certified by one of these organizations. Certified energy auditors may also work as HVAC or weatherization contractors, but they don’t have to.

Home energy audits are a great first step for going electric in your home and they typically cost a few hundred dollars. There are federal, local, and utility incentives available to lower the cost. 

If you recently purchased a home, have never had an energy audit, or you’ve experienced sudden changes in your energy bills or comfort due to drafts or inconsistent temperatures we recommend getting an audit. 

But not all energy audits are created equal. There are often free audits which identify easy opportunities to improve efficiency, like installing LED light bulbs, low-flow shower heads, and smart thermostats. These are great steps, but basic audits will not give you an in-depth understanding of your home. 

This article will help you identify what to look for in a high-quality energy audit.

Areas of concern

A high-quality energy audit will address three main areas: health and safety, comfort, and energy efficiency.

Health and safety

When we talk about health and safety in energy audits we’re usually referring to indoor air quality. Appliances, chemicals, allergens, and other pollutants can all impact your health. A good energy audit will identify sources of poor air quality and suggest solutions. In extreme cases such as high levels of carbon monoxide from leaky fossil-fuel appliances it may be necessary to take immediate action, like turning off the appliance or leaving the home. 

An auditor may also identify other safety hazards like outdated or exposed electrical wiring which could pose a safety risk.

Comfort

After assessing any health and safety concerns one of the first questions your auditor will ask is if there are any parts of your home that are more uncomfortable than others. Be sure to have a list of any issues (however small) that you have noticed or experienced in your home. This could include rooms that are too hot or too cold, drafts, moisture buildup, mold, loud appliances, or odors. These symptoms can help your auditor identify underlying issues that might not be obvious.

Energy efficiency

The older your home, the more likely that air sealing and insulation will save you money by preventing your home from wasting energy. Poor construction in new and remodeled homes may also result in wasted energy and high bills. If you experience a sudden increase in your bills or have consistently high bills — for electricity, natural gas, or water — an energy audit can identify opportunities for cost reductions.

An auditor may not address upgrading to electric appliances during the audit, but they should be familiar with electric upgrades such as heat pumps, heat pump water heaters, and induction stoves as possible solutions to issues in your home. 

Critical energy audit items

Auditor certification

To receive the federal tax credit an auditor must be certified by one of several organizations. Even if you don’t pursue the tax credit choosing a certified auditor is important because they’ll have the training necessary to complete the following tests.

Ask your auditor: What certifications do you have?

Combustion appliance testing

Fossil fuel appliances burn explosive gasses and exhaust pollutants which pose a threat to your health if they aren’t safely vented outside. Combustion appliance testing ensures that carbon monoxide and explosive gas levels aren’t dangerously high.

Ask your auditor: Will you conduct carbon monoxide and explosive gas testing on my [stove, hot water heater, fireplace, furnace, etc.]?

Blower door testing

A blower door test uses a door-sized piece of canvas and a large fan to measure how tightly your home is sealed. The test determines the ACH or CFM (air changes per hour or cubic feet per meter), a single number that measures air leakage in your home. This number helps determine whether air sealing would be a good investment, whether ventilation work might be necessary, and how large a heat pump you would need to heat and cool your home.

Some rebate or incentive programs (including the forthcoming home efficiency rebates) might require a blower door test before or after the work to ensure it meets performance requirements. 

Ask your auditor: Does your audit include a blower door test and will you provide the blower door number (typically expressed as air changes per hour or cubic feet per minute) in your report?

If you need air sealing improvements to your home, it’s common to conduct a blower door test after your home has been air sealed to confirm that the air sealing was effective. This is called a "test out." This may be required for programs such as the Weatherization Assistance Program or to claim efficiency incentives. It’s also a great way to prove that your air sealing work was completed effectively.

Ask your auditor: What is the cost to conduct a second blower door “test out” after air sealing improvements have been made?

Insulation inspection

An auditor should inspect the condition of your existing insulation and identify any areas where insulation should be added or replaced. Attic insulation is often easiest to check, but ideally your auditor will have methods for checking walls as well (see thermal imaging below).

Ask your auditor: How will you inspect existing insulation in the home?

Prioritized list of improvements

Energy audits can produce many suggestions. It’s important that your energy auditor identify the most valuable improvements that can be done to your home to increase health and safety, comfort, and efficiency.

Ask your auditor: After you complete your audit, can we discuss your top 3 to 5 recommendations to improve the home’s safety, comfort, and efficiency?

Important energy audit items

The following are important aspects of an energy audit but may be okay to skip if you can’t find an auditor to complete them.

Thermal infrared imaging and/or diagnostic pressure testing

A blower door number is great for determining the overall air leakage in your home but it doesn’t identify the specific areas that need improvements. Thermal infrared imaging uses an infrared camera during a blower door test to identify the areas of your home with the biggest temperature differences. This indicates where you might have air leakage. In addition to air leakage, infrared imaging may detect where your insulation might be inadequate.

Saving and sharing thermal images with your weatherization contractor can help ensure their work addresses the biggest problem areas in your home.

As an alternative to thermal imaging, your auditor might do diagnostic pressure testing during a blower door test to measure differences between multiple zones in your home, such as hallways and bedrooms. Auditors may also check for leakage around vents, switches and outlets. Diagnostic pressure testing is not always as clear or helpful as thermal infrared imaging but it may be useful if the difference between indoor and outdoor temperatures is not great enough to use infrared imaging.

There are other methods such as smoke testing or manually feeling for drafts, but thermal infrared imaging or diagnostic pressure testing are the most effective. If you think your home is leaking air or needs improved insulation, one of these tests is good to include as part of your audit.

Ask your auditor: Will you provide thermal infrared images in your audit report? If not, what method do you use for identifying air sealing opportunities.

Energy bill analysis

An energy bill analysis identifies your seasonal and typical energy use from historical energy bills. The analysis may also show you how much you might save overall by completing certain home improvements.

Ask your auditor: Will you need copies of my energy bills? What sort of calculations will you conduct to identify where I can best invest my money for energy savings?

Optional energy audit items

Manual J and duct pressure testing

If you plan to get a new heating and cooling system in the near future it can be useful to ask your energy auditor to do duct pressure testing and Manual J calculations at the same time as your audit. This work often costs extra and not every energy auditor does them, but the calculations can be useful for designing a future heat pump system. A high-quality HVAC contractor can often handle these calculations as part of their process, but contractors may be biased to design a larger system than an energy auditor might recommend. An independent opinion can be useful.

Ask your auditor: Are you able to provide a Manual J load calculation? Do you offer duct pressure testing? Are these included, and if not, how much extra do they cost?

Water use analysis

If you have high water bills or live in a drought-prone area consider asking your energy auditor to analyze your water use and make recommendations to improve efficiency. You may also consider reaching out to your local water utility to see if they have programs which can help you decrease your water usage.