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Everything You Need to Know About a Blower Door Test

Energy efficiency has become a hot topic in recent times, and for good reasons. As the world grapples with an unprecedented climate crisis, it has become imperative to take measures to reduce the amount of energy we consume in our daily lives.

A blower door test is one such measure that has gained prominence in recent times. In this blog, Jarboe's Heating, Cooling & Plumbing will explore everything you need to know about a blower door test, its purpose, the steps to conduct it, and its benefits.

What is a Blower Door Test?

A blower door test is a controlled method of measuring the air tightness of a building. Blower door tests using a powerful calibrated fan fitted into an adjustable door frame to generate negative pressure inside the building and test pressure. The resulting pressure differences between the inside and outside of the building creates a situation where all air leakage through the building envelope is revealed. By measuring the amount of air and pressure required to maintain constant air pressure inside throughout the building during blower door testing, it is possible to determine the air tightness of the building.

A blower door test is a diagnostic tool that is usually conducted at the end of the building process, when retrofit works have been carried out on a home or building, or as part of an energy audit. The aim is to detect any uncontrolled outdoor air infiltration and indoor air exfiltration that is happening through the building envelope. By pinpointing the location of warm air leaking, it is possible to take corrective measures to ensure energy efficiency, occupant comfort, air quality, and building durability are all maintained.

Benefits of Conducting a Blower Door Test

Conducting a blower door test on your home can provide several advantages, which include:

Increased Energy Efficiency

A blower door test helps you identify interior air leaks in your home, making it easier to address them. By repairing those leaks, you can make your home more energy efficient by reducing energy consumption and energy costs.

Improved Indoor Air Quality

Air leaks are not only responsible for energy loss but can also cause indoor air quality issues. A blower door test can help you locate these leaks and take appropriate action to address them, which can help to improve indoor air quality.

Increased Comfort and Safety

A blower door test can help you locate areas in your home where hot and cold spots could be most significant. By identifying these areas, you can take corrective measures to balance the temperature in your home, making it a more comfortable and safe environment.

Improved Durability

With a blower door test, you will know how airtight your home is, helping to reduce moisture and mold growth, which can lead to decay, rot, and structural damage over time.

Conducting a Blower Door Test: Step-by-Step

Blower door testing is conducted by a qualified HVAC professional using the following steps:

Step 1: Pre-Test Preparation

Before conducting the first blower door test, the test technician evaluates the structure to determine if it is safe to conduct the test. Interior doors and windows are closed, and all vents, exhaust fans, and fireplaces are temporarily sealed.

Step 2: Setup and Calibration

The blower door fan is attached to the frame of one of the main exterior doors using a mounting panel. All fossil fuel-burning appliances are turned off so they do not operate during blower door tests, including the forced air heating system, sealed combustion water heater, and gas stove. Once secured, the fan is calibrated to measure the pressure of the structure concerning the outside.

Step 3: Use the Blower Door Fan's Air flow

The blower fan is used to draw air out of the building envelope, creating a pressure difference between the inside and outside of the building. Pressure and airflow measurements during this phase of the test enable the technician to measure how much air leaks from the structure and determine the airtightness of the home or building.

Step 4: Detect Air Leaks

During the depressurization phase, the technician investigates the location, size, and severity of air leaks in the building envelope using various techniques. These can include a smoke wand, infrared camera, or even a simple handheld device like a tissue paper. Locating air leakage helps the technician to determine the most cost-effective air sealing solutions to fix the problems.

Step 5: Post-Test Review

After completing blower door testing, a report of the test results, including air changes per hour (ACH), is produced. The homeowner or building owner can use this multi point test report as a basis for taking corrective measures to improve the energy efficiency and the airtightness of the building, including air sealing.

Common Air Leakage Spots Found During Blower Door Testing

When performing a blower door test on your home, it is important to identify and correct any areas that may be showing air leaks. These leaks can cause energy waste and increase monthly expenses on heating and cooling bills. Here are some problem areas that you should pay attention to during blower door testing and how to properly address these issues with an air sealing strategy.


Air leaks around windows are quite common and can lead to energy wastage. Look for gaps between the window frame and the wall, around the window sash, and between the window and the window frame. To address these leaks, sealing them with weatherstripping or caulking will help.


Like windows, doors can also be a major source of air leakage. Pay close attention to gaps between the door and the door frame, as well as the threshold. Weatherstripping and door sweeps can be used to address these issues.

Ventilation System

Improperly installed or clogged vents and ducts can be another source of energy wastage and leaking air. Check for any gaps or damaged ducts and ensure proper installation and sealing.

Recessed Fixture Housing

Recessed lighting fixtures are commonly found in homes, and they can be significant sources of air leakage. Check to see if the fixtures are poorly sealed or have gaps. Installing airtight fixtures or sealing existing ones can help solve this problem.

Unsealed Attic Hatch

The attic hatch can be a major source of air leaks, especially if it is not properly sealed. Check for gaps or poorly fitting hatches, and then seal them with weatherstripping or insulation.

Exterior Walls

Any area where the exterior wall assembly meets other elements of your home, such as pipes or ducts, can be an area for air leakage. Check for gaps and ensure proper sealing to minimize this energy wastage.

Electrical Wiring

Electrical wiring is often overlooked, but it can also contribute to air flowing out of the home. Check around electrical outlets and switch plates for gaps and seal them with foam gaskets.

It's important to note that air leaks can occur anywhere in a building, not just in the areas listed above. Regular blower door testing can help to identify problem areas and guide improvements to increase energy efficiency and indoor air quality. By paying close attention to these problem areas and taking the necessary steps to address them, you will be well on your way towards creating a more energy-efficient home.

Duct Sealing to Eliminate Air Leaks

One of the biggest challenges homeowners face is maintaining the energy efficiency of their homes. A major contributor to this is the presence of air leaks, which can cause the loss of hot or cold air and put a strain on your HVAC system. One way to detect these pesky leaks is through blower door testing.

Blower door testing involves using a special fan system to measure the air pressure within the home. By simulating outdoor conditions, technicians can evaluate how much air is escaping through doors, windows, and various other openings. This includes finding leaks in the duct system, which can be a major cause of energy loss.

Jarboe's understands the importance of duct sealing in order to improve the energy efficiency of your home. Professional duct sealing can eliminate leaks and prevent air from escaping through the ducts. With their skilled technicians, Jarboe's uses state-of-the-art equipment and materials to ensure that all leaks are sealed effectively.

Not only does duct sealing improve energy efficiency, but it also improves the air quality in your home. Leaks in the duct system can allow for the entrance of harmful pollutants such as dust, mold and radon, which can cause health problems. With Jarboe's expert duct sealing services, you can be assured of an airtight, healthy home environment.

Blower Door Tests for Louisville Home and Business Owners

A blower door test can help you identify air leaks, which can potentially save you money on energy costs, improve your indoor air quality, and increase the comfort and safety of your home. If you're looking for a reliable and professional contractor to conduct a blower door test in Louisville, Jarboe's is your go-to company.

With our experienced technicians and state-of-the-art technology, you can be confident that you are getting accurate test results and solutions to improve the energy efficiency and air tightness of your home. Contact us today to schedule blower door testing and professional services to air seal your ductwork.

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