Other DIY Air Leak Detection Methods 

You can also detect air leaks by shining a flashlight over potential gaps at night. 

You will need a partner to observe the house from outside for large gaps or 

cracks that will show up as rays of light. This method may not locate small 

gaps. You can also detect air leaks by shutting a door or window on a piece of 

paper. If you can remove the paper without tearing it, you have an air leak. 

Professional Home Energy Assessment

The professional home energy assessment is usually a much more detailed and 

quantitative evaluation of the energy efficiency of a house (or any building). The 

energy auditor uses special equipment to measure the rate of air flow between 

the inside and outside of the house. 

Guide to 

Home Energy 

Assessments 

A home energy assessment 

is the essential first step to 

lowering your energy bills. 

Why Have a Home Energy 

Assessment? 

A proper home energy assessment 

(also called a home energy audit) will 

tell you how much energy you use in 

your house, the most cost-effective 

measures you can take to improve the 

energy efficiency of your home, and 

how to save money on energy bills. 

Do-It-Yourself Home Energy 

Assessment

You can conduct a simple home 

energy inspection yourself, or hire 

a professional for a comprehensive 

analysis. The DIY assessment 

involves a simple but diligent walkthrough of your home during which 

you carefully look at the primary 

areas where air leaks occur: 

•	 Look at places where different 

materials, such as brick and wood 

siding, meet - between foundation 

and walls, and between chimney 

and siding.

•	Inspect the area around electrical 

outlets, switch plates, windows 

and door frames, baseboards, attic 

hatches, wall or window-mounted 

air conditioners, mail chutes, 

electrical and gas service entrances, 

cable TV and phone lines, and vents 

and fans.

•	Check to see that caulking and 

weather stripping are applied properly and are in good condition. 

A home energy assessment involves checking your home for areas (indicated by stars in the above picture) 

where you can save energy and money. 

Depressurization Test

If you have difficulty locating air leaks, try conducting a basic building depressurization test 

(ideally on a cool, windy day).

1. Close all exterior doors, windows, and fireplace flues.

2. Turn off all combustion appliances, including gas burning furnaces and water heaters. 

Note: If you do not wish to turn off your furnace, you can omit step 2 and go to step 3.

3. Turn on all exhaust fans that blow air outside, such as bathroom fans or stove vents. 

4. Light a smoke candle or incense stick and pass it around the edges of common leak 

areas. If smoke is drawn into or out of a room, then there is an air leak.

continued >
Finding a Certified Provider 

Make sure you use a certified energy 

auditor. Such auditors are typically 

licensed contractors in the home 

building and remodeling industry 

with experience installing heating 

and cooling systems, windows, and 

lighting. To find a certified auditor, 

check with your local electric or gas 

utility provider, your local state or 

local government energy or weatherization office, or follow the ENERGY 

STAR® link under Further Reading. 

Preparing for an Assessment 

Before the energy auditor arrives, 

make a list of any existing indoor 

problems you have noticed, such as 

condensation and uncomfortable or 

drafty rooms. Have copies or summaries of recent energy bills to share 

with the auditor. The auditor should do 

an initial walkthrough of your home to 

determine daily energy usage patterns, 

both overall and in specific rooms.

Assessment Techniques and 

Equipment 

The two most common techniques for 

carrying out a home energy assessment include the blower door test and 

a thermographic (infrared camera) 

scan, which are often done together. 

During the course of the assessment, 

the auditor may also inspect your 

heating and cooling systems, test for 

natural gas leaks, and check to see if 

your home is properly ventilated. 

Blower Door Test

The blower door test is designed to 

measure the airtightness of a house. 

A powerful fan called a blower door 

is mounted into a flexible panel and 

frame that fits in a doorway. The fan 

draws air out of the house, resulting 

in lower pressure inside the house. 

This allows outdoor air to flow in 

through unsealed gaps and other 

unwanted openings. Using a smoke 

pencil, the auditor can then determine 

the location of air leaks. 

Make sure the auditor uses a 

calibrated blower door. A calibrated 

blower door is connected to a pressure gauge called a manometer that 

measures the pressure difference 

between two locations as the fan is 

running. This results in a quantitative 

measurement of the air flow through 

the house. Uncalibrated blower doors 

can identify air leaks in the home, but 

not the amount of air leakage.

The auditor may also use a duct blower, 

a variable speed fan attached to a duct 

system with a hose to measure the 

amount of air leakage within ductwork. 

Thermographic Scan

A thermographic scan involves the 

use of an infrared scanner to detect 

differences in temperature in a building, in particular along walls, roofs, 

and around windows and doors. These 

differences show up in a video or 

camera still image as whiter (warmer) 

or darker (cooler) areas. Auditors use 

the images to determine the location of 

air leaks. When done together with a 

blower door test, air leaks show up as 

black streaks in the infrared image.

After the Assessment

Once the assessment is completed, 

the energy auditor should provide 

you with a report of the findings and 

recommendations for improvements. 

You can make an informed decision 

about what upgrades to make to your 

home, based on these findings. You 

may only need to air seal small gaps 

and add attic insulation. Or it may be 

cost-effective for you to make more 

substantial upgrades, such as replacing heating and cooling equipment. 

Cost & Financials

A professional home energy assessment can cost from approximately 

$100 to $500. Many contractors will 

perform the assessment at a reduced 

rate provided that you hire them to 

carry out subsequent upgrades. Tax 

rebates for assessments are available to lower income families, and 

the U.S. Department of Energy’s 

Weatherization Assistance Program 

also provides states with funding to 

help low income families weatherize their homes. There are also tax 

credits and incentives for switching to 

energy-efficient products. Please see 

below for more information. 

Further Reading 

DOE Weatherization Assistance 

Program

www.eere.energy.gov/wip/wap.html

Energy Savers: Home Energy 

Assessments 

www.energysavers.gov/

energy_assessments

Home Performance with ENERGY 

STAR Locations 

www.energystar.gov/index.

cfm?c=home_improvement.

hm_improvement_hpwes_partners

Financial Incentives

Tax credits, incentives and rebates may be 

available in your area. Please visit 

www.energysavers.gov/taxcredits for more 

information.

EERE Information Center

1-877-EERE-INFO (1-877-337-3463)

www.energysavers.gov

Printed with a renewable-source ink on paper containing 

at least 50% wastepaper, including 10% post consumer waste.

DOE/EE-0383 • February 2011