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What is a Blower Door Test?

By Mid Michigan Spray Foam · July 25, 2026

What is a Blower Door Test — Mid Michigan Spray Foam

“blower door test near me”

“spray foam insulation contractor in Owosso”

“home energy audit Lansing MI”

“air sealing services Flint”

“why is my house drafty in Michigan?”

You’re in the right place.

Blower door testing is one of the most important tools used in modern building science to measure air leakage in homes and commercial buildings, and it directly impacts how well your insulation performs.

Whether you’re in Owosso, Lansing, Flint, Howell, Saginaw, Midland, Brighton, or Mount Pleasant, understanding blower door testing can help you save money and build smarter.

What Is a Blower Door Test?

A blower door test uses a calibrated fan mounted in an exterior doorway to:

Depressurize or pressurize the home

Measure how much air leaks through cracks and gaps

Quantify air leakage in CFM50 (Cubic Feet per Minute at 50 Pascals)

It tells you how drafty your building really is.

Why Air Leakage Matters in Michigan

Michigan’s climate (Zone 5/6) means:

Humidity problems in summer

Mold and condensation issues

Insulation alone does not stop air movement.

That’s where blower door testing and proper air sealing come in.

How Blower Door Testing Connects to Spray Foam Insulation

Spray foam insulation is one of the only insulation materials that:

Reduces moisture movement

Fiberglass and cellulose slow heat transfer, but they do not stop air leakage.

When we perform a blower door test before and after installing spray foam in areas like:

We can measure real, quantifiable improvement.

This is why people searching for:

“best insulation for Michigan homes”

“spray foam vs fiberglass”

“energy efficient insulation Lansing”

“closed cell spray foam cost Flint”

Often end up learning about blower door testing.

Because air leakage is the hidden energy thief.

What Happens During a Blower Door Test?

A powerful fan is installed in an exterior door.

The home is depressurized.

Air is pulled through all leaks.

We use smoke pencils or infrared cameras to identify leakage areas.

We measure total air changes per hour (ACH50).

This gives a clear picture of:

Where the biggest leaks are

What insulation or air sealing improvements will make the biggest difference

What Is a “Good” Blower Door Number?

Typical results in Mid-Michigan:

Older homes (pre-1990): 7–12 ACH50

Energy-efficient home: 3–5 ACH50

High-performance home: <3 ACH50

Modern building codes increasingly require lower ACH50 numbers.

If you’re building in areas like Lansing, Brighton, Howell, or Grand Blanc, blower door testing is often required for inspection approval.

Where Air Leakage Commonly Happens

In homes across Owosso, Corunna, Perry, Durand, Flint, and Saginaw, we commonly find leaks at:

Spray foam insulation is especially effective in these areas because it expands and seals gaps.

Blower Door Testing & Energy Savings

Reducing uncontrolled air leakage can:

Improve indoor air quality

For homeowners in Midland, Bay City, Mount Pleasant, Lansing, and Howell, energy savings often offset insulation upgrades over time.

Why Spray Foam Performs So Well Under Blower Door Testing

Improves R-value per inch

Great for attics and wall cavities

When paired with blower door verification, you’re not guessing, you’re measuring.

Who Needs a Blower Door Test?

You should consider blower door testing if:

You’re finishing a basement

You’re building new construction

You’re upgrading insulation

You want lower energy bills

You’re installing spray foam

You’re preparing for code inspection

It’s especially common in new builds around Lansing, East Lansing, Brighton, Howell, and Grand Blanc.

Building Science in Simple Terms

Building science looks at how:

Blower door testing measures air movement.Spray foam controls air movement.

That’s why the two are closely connected.

Final Thoughts for Mid-Michigan Property Owners

OwossoLansingEast LansingFlintGrand BlancFentonHowellBrightonSaginawMidlandBay CityMount PleasantCorunnaDurandPerry

Understanding blower door testing can help you make smarter insulation decisions.

Spray foam insulation paired with proper air sealing verification is one of the most effective ways to improve energy efficiency in Michigan’s demanding climate.

Learn more

Explore our Blower Door Testing service, or get a free quote.

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