A picture of the doorway with a blower door test attached in our attainable net zero energy solar home. The door is opened with the testing machine creating an airtight seal and a fan inside it.

Is your home drafty? Do you feel the cold air regularly? If so, then it’s time to find out what’s going wrong. A blower door test can help identify any leaks in your home that let outside air in or see if inside conditioned air is escaping!

Both commercial buildings and residential properties should occasionally consider the benefits of a blower door test, especially if you’re concerned about air leakages and overall energy efficiency.

If you put forth the time and expense for one of these tests, what kind of benefits can you expect? In today’s article, we’ll explain blower door testing in detail and then expound further on the above benefits.

We’ll also touch on the cost of blower door testing, money savings and wealth-building, and a few more points.

The Benefits of Doing a Blower Door Test

  • Measure your home’s exact amount of air leakage.
  • Discover especially leaky spots in the house with use of smoke tests.
  • See where hot or cold air is coming in with an infrared camera.
  • Pass building code requirements when blower door tests are required for renovations or new home builds.
  • Gives an overall picture of how tight the building envelope is, and if you need mechanical ventilation, make sure the air stays healthy and fresh.

What Is a Blower Door Test?

Before you can decide whether you want a blower door test for your home, you need to know what this test is. 

Blower door testing involves certified professionals coming to your home to check whether the property has any air leaks, often as part of an energy audit. They use a machine that attaches to your sealed doorway, which depressurizes the home by using a fan to force air out of the house. This measures how leaky the home is.

The operator doing the testing should be certified through the Residential Energy Services Network (RESNET) or the Building Performance Institute (BPI).

A Quick Note on Insulation vs. Air Leakage

It’s important to note that insulation may not have a direct relationship to air leakage or blower door tests. Insulation acts as a blanket over your own – but it doesn’t necessarily mean your home will have a tighter building enveloper or be less leaky. This is why a blower door test and checking air leakage is of higher priority than insulation on these projects in most cases.

A man standing near the doorway with a blower door test installed. The main is reading the measurements so we can look at the benefits of blower door test.
Before we started our renovation – testing our net-zero home renovation project with a blower door test. The house scored a 6.8 ACH50, indicating a mediocre score yet quite a leaky house.

How a Blower Door Test Works

On the day of the test, the operator will mount a fan to one of your exterior doors around a canvas-covered frame. The exhaust fan will depressurize the air, which is another way of saying the fan sucks the air from your home. This is how the testing operator can tell whether your home has openings, leaks, or cracks, as the air will come through these unsealed spaces.

With a pressure gauge, the operator will determine how much air is being released. The result is expressed in air changes per hour (at 50 pascals of pressure) or ACH50. The ACH is dictated by your home air volume as well as the dimensions of the property. For a North American home, an ACH of about 3-6 is considered good. If your home is older, expect a considerably higher ACH rating, maybe 6 to 10 ACH and up.

Southwest Florida – An Example

For example, in Florida, you are required to get a blower door test for any new home build or renovation, and it has to score under 7 ACH50. If it scores under 3 ACH50, you are required to install mechanical ventilation.

Single vs. Multi-Point Blower Door Testing

You may request either single-point or multi-point blower door testing. A single-point test will add or remove pressure at a rate no higher than 50 pascals. Then the operator will use a manometer for tracking air leakage. With a multi-point blower door test, the operator will do a few readings at pressures of 0 to 60 pascals to identify tricky leaks. 

Shows a man with clear large duct tape taping over the HVAC intake return in the ceiling during our blower door test.
Bud Fahey of Florida Blower Door helped us to decrease air leakage in our first net-zero home renovation project by 44%! He’s shown here sealing and testing the air leakage in the HVAC duct systems.

How Long Does Getting A Blower Door Test Done Take?

Getting a blower door test done isn’t very time-consuming. The operator will be in and out in a few hours if that. Setting up the testing may take about an hour and a half, and the test itself requires five to 15 minutes.

Should the blower door test find a leak, you have to determine how you want to repair and optimize your home. 

Some More Benefits of Optimizing Your Home Based on the Blower Door Test Results

Now that you understand how blower door tests work, let’s discuss the multitude of benefits from acting upon the information that blower door testing can tell us. We touched on in the intro. Because just like every other test – nothing changes unless you actively make upgrades or optimizations based on the results. 

Your Home Can Become More Energy Efficient

Energy efficiency is something you care very much about, which is why it’s a good idea to schedule a blower door test or an energy audit sooner than later. If your home has air leaks throughout, that means in the spring and summer, hot air comes in. You can’t spend all day sweating, so you crank your air conditioner.

And the opposite happens in the winter. Either way, the air is leaking in and out, stressing your heating and cooling systems more than they have to be.

A Quick Note On Being Green With Heating and Cooling

AC units use refrigerants, the most common of these being hydrofluorocarbon or HFC. On the greenhouse gas potency scale, HFCs are far more concerning greenhouse gas than even carbon dioxide. When your home has no air leaks, you don’t have to run your AC nearly as often, reducing your carbon footprint and making your home greener. 

Might Help You Get More Years Out of Your HVAC System

Another downside of running your air conditioner fervently all summer is that you strain the unit. Even if you have expensive central cooling, no HVAC unit is meant to last forever. The same is true of your furnace or heater, by the way. Blasting the heat can be the only way to combat that frigid air chill from your leaky home in the winter, but overuse will kill your heater sooner than later.

Shows an infrared camera with yellow areas on the screen, showing higher heat infrared readings on the HVAC duct return vent in our net-zero home.
In the picture above you can see us using the infrared camera during the blower door test on our first net-zero home renovation project. You can see the heat coming in through the air vent, and it also shows a piece of fiberglass insulation missing above the drywall. It was about 90 degrees outside during the Florida summer.

Having To Replace Your HVAC Early

According to HomeAdvisor, the average cost of a new heater in 2021 is $2,000 to $40,000, depending on your home size. An oil-running heater can cost $6,750 to $10,000, an electric heater $2,000 to $7,000, and a gas heater $3,800 to $10,000. If you want a geothermal heater, that’s going to be the most expensive of all at $10,000 to $40,000 and up.

Those are just the costs for the heater itself. Installation, HomeAdvisor says, is $4,467 on average but may be as high as $6,320.

If you need to replace your air conditioner, PickHVAC notes that a new AC in 2021 starts at $2,375 for cheap models and can cost upwards of $7,500 for a higher-end air conditioner. 

Prematurely having to replace these units is a major financial hit. You want to get all the years you can out of your HVAC. 

Bumps up Your Home’s Resale Value

Everyone wants their home to have a high resale value, but you don’t need to remodel your kitchen to get there. Energy efficiency is top of mind for today’s homebuyers. By making your home eco-friendlier after getting your blower door test results, your home will be attractive to buyers. 

Betters the Quality of Indoor Air

Outdoor air can be polluted with contaminants such as ozone, nitrogen dioxide, sulfur dioxide, and lead. You normally get a reprieve from these health dangers when you’re in your home, but that’s not the case when outdoor air constantly leaks into your home. You might as well leave your front door wide open, as it’s practically the same thing.

If you’re prone to allergies, the lower-quality indoor air can make your life miserable. You won’t be able to escape pollen even behind closed doors, so your allergy symptoms will persist and may be more severe. 

Money Savings And Wealth-Building Benefits

A blower door test can help you to pocket more money in so many ways. First, as we talked about in the paragraphs above, you’ll get more years out of your current HVAC units with less air leakage, which can save you thousands and thousands of dollars. 

Your energy bill will go down as your reliance on your heater and AC does the same. The savings over the short-term and especially in the long-term will be like putting money back in your pocket month after month. 

Increase Home Value

With your home resale value higher, you’d likely earn more money for your home if you decided to sell. Even if you choose to stay, with a blower door test, you’re preventing disastrous scenarios that can cost you tens of thousands of dollars in some cases to repair or replace, all while saving on your monthly energy bills to boot.

After all, when air leaks, it’s usually very warm, even in the winter. If the warm air enters your home’s wall assembly, it can become moist air that’s a hotbed for mold and mildew. Redoing the walls of your home–even if it’s just a few rooms–is going to be an extremely costly endeavor.  

How Much Does a Blower Door Test Cost?

For all the benefits you can reap from a blower door test, you may be surprised to learn that testing costs $300 to $400 as a national average, according to Family Handyman. That said, we do recommend you contact a blower door testing local operator for a quote, as the cost could be higher or lower than stated.  


A blower door test is incredibly beneficial, saving you so much money over time that the few hundred dollars you may spend on the test is small potatoes.

While you can also be confident that your home is more energy-efficient, this is also one of the lowest-hanging fruits and one of the first things you’ll want to do on your energy efficiency journey.

One Comment

  1. Thank you for discussing how a blower test works. I am starting a new business and I want to have air testing done to keep things safe. I will find an air testing service locally to assist.

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