What Is a Blower Door Test?
A blower door is a tool used to measure air leakage in homes. It uses a variable-speed fan mounted in a door frame to create pressure which helps identify where and how much air is escaping. It’s a key tool in diagnosing and improving home performance.
Pro tip: A smart air sealing strategy can help you hit blower door targets for rebates–without slowing down your build. Avoid delays and get ahead of common on-site corrections with these air sealing tips →
What’s a Good Blower Door Score?
If you’ve ever wondered how airtight your home really is, the blower door test is the go-to method for measuring it. But what score should you be aiming for?
3ACH50 is the magic number. If you can get there, you’re doing pretty darn good.
| ACH Score | Meaning |
|---|---|
| 5 ACH | Current building code requirement in North Carolina |
| 4 ACH | Target to qualify for Duke Energy rebates |
| 3 ACH | Considered a “tight” house |
| 2 ACH | Typically achieved with spray foam insulation in most markets |
| 0–1 ACH | Passive House standard; requires advanced air sealing strategies |
Why Blower Door Scores Matter
Lower is better when it comes to blower door scores. A lower score means less air leakage which improves comfort, indoor air quality and durability. While also increasing your odds to qualify for utility rebates, like Duke Energy’s HERO code.
Pro tip: Getting to 3ACH50 isn’t magic — it’s strategy. Don’t let air leaks cost you rebate money. Ask us about our air sealing services to keep your builds tight and your timelines on track.
Want to Hit 3ACH? Start Here!
Check out some of our most popular guides for air sealing tips and getting your blower door score down:
- Wall Top Air Sealing – What to Know
- Top 5 Air Sealing Strategies for Townhome Party Walls
- Top 5 Air Sealing Tips to Save Time & Money
- Energy Rebates & Incentives
Ask us how to get to 3ACH — we have the solutions! #buildtightventilateright
