Blower Door Testing Truro MA
Certified blower door testing in Truro - we measure your home's air-tightness in ACH50, pinpoint leaks, and document a passing result for your building permit.
Air-tightness at a glance
Blower Door Testing Truro MA
A blower door test is the code-required way to prove how airtight a home in Truro really is. A calibrated fan depressurizes the house to 50 Pascals so we can measure exactly how much air leaks through the envelope, reported as air changes per hour (ACH50). New construction must reach 3.0 ACH50 or lower, while remodels are allowed up to 5.0 ACH50.
| Project type | Max ACH50 | Notes |
|---|---|---|
| New construction | 3.0 or lower | Mandatory blower-door test under R402.4.1.2 |
| Remodel / alteration | 5.0 | Realistic target for existing assemblies |
| Addition < 1,000 sq ft | Exempt* | May be exempt from testing (R502.3.1) |
| Passive House / Specialized | 0.6 | Whole-building test, Phius/PHI protocol |
*Confirm with your local building department. Requirements per the 2025 MA Stretch Energy Code Technical Guidance.
How Blower Door Testing Works in Truro
The fan mounts in an exterior doorway and holds the home at a fixed 50-Pascal pressure difference - about what a 20 mph wind would exert. The airflow required to maintain that pressure, in CFM, converts to ACH50 using the home's conditioned volume.
The code converts the result to Q50 (CFM at 50 Pa) with Q50 = (Volume × ACH50) ÷ 60. A 2,700 sq ft home at 2 ACH50 works out to roughly 810 CFM50.
Keeping Heat In During Truro Cold Spells
During a New England cold snap the stack effect goes to work: warm indoor air rises and slips out near the top of the house, and that pulls cold outdoor air in through gaps down low. The colder it gets, the harder this effect pushes - so a leaky home loses the most heat exactly when it can least afford to.
Once the leaks are found and sealed, the home retains heat far longer between heating cycles. Floors stay warmer, temperatures hold steady on windy nights, and the reduced heating load shows up directly on winter utility bills.
Lower heating load
Less infiltration means a smaller winter heat-loss load and equipment that can keep up.
Retain paid-for heat
Warm air stays in the living space instead of escaping out the top of the house.
Steadier comfort
Fewer cold-floor drafts and a temperature that holds between heating cycles.
Where Truro Homes Leak Air
During depressurization the leaks are exaggerated, making them easy to find. In Barnstable County's older housing stock the usual suspects are rim joists, top plates, attic hatches, recessed lights, and penetrations for plumbing and wiring. Coastal and exposed sites feel wind-driven infiltration most, so a tight, verified envelope pays back quickly here.
Best Fit for Projects Like
- Custom and high-performance builds
- Pre-drywall diagnostic testing for builders
- New single-family homes needing a code compliance test
- Mass Save incentive and rebate projects
- Multi-family and townhouse units
Blower Door Testing Truro MA Facts
Fail and reseal
If a result comes in above target, the leaks are located and sealed and the home is retested - the goal is a documented pass, not a single reading.
Retaining the heat you paid for
A tight, tested envelope keeps the warm air you have already paid to heat inside the living space rather than letting it leak out the top of the house.
Small-addition exemption
Additions under 1,000 sq ft can be exempt from air-leakage testing under R502.3.1, though the connected existing home may still benefit from a test.
Smaller design heating load
Because infiltration is a major line in the winter heat-loss calculation, verifying tightness lets a designer lower the design heating load and right-size equipment.
Trusted for Blower Door Testing Truro MA
One of the most reliable companies that I've worked with in Somerville, Massachusetts.
I worked with this HERS rating company in South Boston on a remodel project and was able to get back 30,000 in rebates.
Great job — thank you so much for your service. They helped me with the HERS ratings and guided me through the building process to help me reach passing scores! Thank you!
Our Massachusetts Service Locations
Serving clients from our Massachusetts locations in Everett, Somerville, and Framingham.
Everett Location
371 Main St
Everett, MA 02149
Somerville Location
519 Broadway
Somerville, MA 02145
Framingham Location
68 South St
Framingham, MA 01702
FAQ About Blower Door Testing Truro MA
Do you work with builders and homeowners?
We work with builders, remodelers, designers, and homeowners - from single tests for permit sign-off to pre-drywall diagnostics that catch problems early.
Can a blower door test find where my home is drafty?
Yes. Depressurizing the home exaggerates the leaks so a rater can pinpoint exactly where outdoor air is entering, which guides targeted air sealing.
How tight is a Passive House?
Passive House projects on the Specialized Code path target around 0.6 ACH50 - roughly ten times tighter than base code - verified with a whole-building blower-door test.
When in construction should the test be done?
A pre-drywall diagnostic test is ideal for catching leaks while they are easy to reach, followed by a final compliance test near completion.
Why does my house feel drafty and cold in winter?
Much of that is the stack effect - warm air leaking out up high draws cold outdoor air in through gaps down low, chilling floors and lower rooms. A blower door test pinpoints exactly where that air is entering so it can be sealed.
What happens if my home fails the test?
The rater locates the leaks with smoke, an infrared camera, or by feel, those areas are sealed, and the home is retested until it meets the target.
Get Started With Blower Door Testing Truro MA
Book a certified blower door test and get a permit-ready air-tightness report. Call 617-501-6788.
