Blower Door Testing Pembroke MA
Certified blower door testing in Pembroke - 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 Pembroke MA
A blower door test is the code-required way to prove how airtight a home in Pembroke 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 Pembroke
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 Pembroke Cold Spells
In winter the biggest enemy of a warm home is often invisible air movement. The stack effect drives heated air out through the top of the envelope and draws frigid air in near the floor, robbing heat all season - Cornell extension research describes it plainly as the effect that steals warmth from your home every winter.
A tight, tested envelope shrinks the infiltration share of your heating load. That lets the equipment keep up during cold spells, holds rooms at a steadier temperature between cycles, and often lets a designer right-size the heating system rather than oversizing it to cover leakage.
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 Pembroke Homes Leak Air
During depressurization the leaks are exaggerated, making them easy to find. In Plymouth 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
- Homes chasing Passive House or net-zero targets
- Drafty existing homes seeking targeted air sealing
- Certificate-of-occupancy sign-off
- Multi-family and townhouse units
- Custom and high-performance builds
Blower Door Testing Pembroke MA Facts
Helping heat keep up
Sealing the envelope shrinks the infiltration portion of the heating load, so the furnace or heat pump can actually hold temperature through a cold spell instead of running flat-out and falling behind.
What a blower door measures
A blower door is a calibrated fan sealed into an exterior doorway. It pressurizes and depressurizes the home to 50 Pascals so the exact volume of leaking air can be measured in cubic feet per minute.
Coastal wind exposure
Homes near the coast face steady wind-driven infiltration, so a tight, well-tested envelope pays back faster in exposed and shoreline locations.
Finding the leaks
During depressurization a rater uses a smoke pen, an infrared camera, or simply feel to locate leaks at rim joists, top plates, recessed lights, and wall penetrations.
Trusted for Blower Door Testing Pembroke MA
As a builder, I need accurate and dependable HERS ratings to keep projects on track. This company never disappoints. Always on time, always professional.
Had a pleasure working with Dom. Everything in the building turned out great and air tight for the coming winter.
Very thorough, informative and prompt! Highly recommend!
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 Pembroke MA
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.
What is a blower door test?
It is a diagnostic that measures how airtight a building is. A calibrated fan mounted in a doorway pressurizes or depressurizes the home to 50 Pascals and measures the airflow needed to hold that pressure, which is reported as ACH50.
How long does a blower door test take?
For a typical single-family home the test itself usually takes well under an hour once the fan is set up and the home is prepared.
What is the threshold for a remodel?
Remodels and alterations to existing homes are allowed up to 5.0 ACH50, a more realistic target given that older assemblies are harder to seal than new framing.
Will sealing my home cause moisture problems?
No - controlled tightness plus proper ventilation actually reduces moisture problems, because you stop humid air from moving through and condensing inside assemblies.
What documentation do I receive?
You receive the measured ACH50 result on a RESNET/HERS-style report suitable for the building department, plus notes on any sealing performed.
Get Started With Blower Door Testing Pembroke MA
Book a certified blower door test and get a permit-ready air-tightness report. Call 617-501-6788.
