Blower Door Testing Southwick MA
Certified blower door testing in Southwick - 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 Southwick MA
A blower door test is the code-required way to prove how airtight a home in Southwick 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 Southwick
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 Southwick 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.
Sealing and verifying the envelope with a blower door test blunts that stack effect. You keep more of the heat you have already produced, cold-floor drafts fade, and the furnace or heat pump can actually hold temperature through the coldest stretches instead of running flat out and falling behind.
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 Southwick Homes Leak Air
During depressurization the leaks are exaggerated, making them easy to find. In Hampden 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
- Gut renovations and deep-energy retrofits
- Additions over 1,000 sq ft that trigger testing
- New single-family homes needing a code compliance test
Blower Door Testing Southwick MA Facts
The ACH50 metric
Results are reported as ACH50 - air changes per hour at 50 Pascals. It tells you how many times per hour the home's entire volume of air would be replaced under that test pressure.
Air leakage and heating cost
Uncontrolled air leakage can raise a home's heating and cooling costs by 30% or more, which is why the code treats envelope tightness as a mandatory measure.
New construction target
New residential construction in Massachusetts must test at 3.0 ACH50 or lower. Tighter is better, and many high-performance builders aim well under that number.
Who needs a test
New homes, gut renovations, many additions, and Mass Save incentive projects all rely on a blower-door number to demonstrate performance.
Trusted for Blower Door Testing Southwick MA
Very thorough, informative and prompt! Highly recommend!
Top notch service from start to finish.
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 Southwick MA
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.
Is a blower door test required by code?
Yes. Air-leakage testing is mandatory under R402.4.1.2 for new residential construction, verified with a blower door at 50 Pascals.
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.
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.
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.
How is ACH50 converted to CFM?
The code uses Q50 = (conditioned volume x ACH50) / 60. For example, a 2,700 sq ft home with 9 ft ceilings at 2 ACH50 equals about 810 CFM50.
Get Started With Blower Door Testing Southwick MA
Book a certified blower door test and get a permit-ready air-tightness report. Call 617-501-6788.
