Blower Door Testing Randolph MA - Quick Facts
Local energy code in Randolph
- New construction and major renovations in Randolph follow the Massachusetts Stretch Energy Code. IECC Climate Zone 5A.
- Massachusetts has three energy-code levels - base (2021 IECC), Stretch, and Specialized (Opt-In) - and Randolph is on the Stretch Code.
Blower door requirement in Randolph
- New homes in Randolph must test at 3.0 ACH50 or tighter under the Massachusetts Stretch Code.
- Air-leakage testing is mandatory, measured with a calibrated blower-door fan to the RESNET / ASTM protocol - there is no inspection-only substitute for the result.
- Companion duct leakage limit: 4 CFM25 per 100 sq ft of conditioned floor area when ducts run outside conditioned space.
- Same-day preliminary results; final report in 24-48 hours, filed with the Randolph building department.
What you can get back: 2026 Mass Save
- A tight result unlocks Mass Save all-electric incentives ($7,500 to $25,000 per new single-family home); an all-electric renovation testing at 3.0 ACH50 or better reaches the Level 2 tier, up to $30,000.
- Incentives require a Mass Save-approved, RESNET-certified HERS rater.
RESNET-certified · 15,000+ ratings completed · 5.0 stars across 135 Google reviews · (617) 501-6788
Blower Door Testing Randolph MA
Certified blower door testing in Randolph - 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 Randolph MA
A blower door test is the code-required way to prove how airtight a home in Randolph 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 Randolph
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 Randolph 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.
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 Randolph Homes Leak Air
During depressurization the leaks are exaggerated, making them easy to find. In Norfolk 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
- Additions over 1,000 sq ft that trigger testing
- New single-family homes needing a code compliance test
- Drafty existing homes seeking targeted air sealing
- Certificate-of-occupancy sign-off
Blower Door Testing Randolph MA Facts
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.
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.
Moisture protection
Controlling air movement also controls the moisture that rides with it, protecting insulation and framing from condensation and mold over the life of the home.
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.
Trusted for Blower Door Testing Randolph MA
I had an excellent experience. Friendly, knowledgeable, and very responsive. I will definitely be coming back.
One of the most reliable companies that I've worked with in Somerville, Massachusetts.
Had a pleasure working with Dom. Everything in the building turned out great and air tight for the coming winter.
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 Randolph MA
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.
Do additions need a blower door test?
Many do, but additions under 1,000 square feet can be exempt from air-leakage testing under R502.3.1. We can confirm what your specific project requires.
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.
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.
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 does air sealing help during a cold spell?
In winter the stack effect drives warm air out the top of the house and pulls cold air in low down, and it gets stronger the colder it is. A tight, tested envelope blunts that effect, so you retain more of the heat you have paid for and your heating system can keep up during a deep freeze.
Get Started With Blower Door Testing Randolph MA
Book a certified blower door test and get a permit-ready air-tightness report. Call 617-501-6788.
HERS Ratings Across Randolph and Nearby Communities
Home Energy Efficiency Consultants rates new homes, additions, and major renovations throughout Randolph — including Randolph Center, North Randolph, and South Randolph. Every Randolph project is filed with the Town of Randolph Building Department, and we handle the energy model, blower door and duct leakage testing, and the compliance paperwork from start to finish.
We also serve the communities right around Randolph, including Milton, Braintree, Holbrook, Canton, and Stoughton. Our Somerville office at 519 Broadway is the closest of our four Massachusetts locations — see our Somerville office or call (617) 501-6788 to get a Randolph rating on the schedule.
More Massachusetts Towns We Serve
Certified HERS ratings, blower door testing and energy code compliance across all 351 Massachusetts cities and towns.
