Blower Door Testing Arlington MA - Quick Facts
Local energy code in Arlington
- As of January 1, 2024, Arlington enforces the Massachusetts Specialized (Opt-In) Energy Code on top of the Stretch Code baseline - IECC Climate Zone 5A.
- The Opt-In code goes further than the Stretch baseline: new fossil-fuel homes must be pre-wired for electrification and include on-site solar where roof space allows.
- New all-electric homes rely on heat pumps for heat and hot water; large fossil-fuel homes over 4,000 sq ft must hit net-zero (HERS 0), and multifamily over 12,000 sq ft must be Passive House.
- Arlington also participates in the Massachusetts Municipal Fossil Fuel-Free Building Demonstration Program - new construction and major renovations must be built fossil-fuel-free (all-electric), a step beyond the Specialized Code.
Blower door requirement in Arlington
- New homes in Arlington must test at 3.0 ACH50 or tighter under the Massachusetts Stretch Code (Specialized Code town).
- 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 Arlington building department.
Mass Save rebates for Arlington (2026)
- 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 Arlington MA
Certified blower door testing in Arlington - 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 Arlington MA
A blower door test is the code-required way to prove how airtight a home in Arlington 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 Arlington
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 Arlington 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 Arlington Homes Leak Air
During depressurization the leaks are exaggerated, making them easy to find. In Middlesex 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
- Multi-family and townhouse units
- Custom and high-performance builds
- Certificate-of-occupancy sign-off
- Drafty existing homes seeking targeted air sealing
- Pre-drywall diagnostic testing for builders
Blower Door Testing Arlington MA Facts
The reference scale
For perspective, a very leaky older home can exceed 11 ACH50, current code sits at 3.0 for new builds, and certified Passive House projects reach 0.2 to 0.6 ACH50.
The winter stack effect
In cold weather warm indoor air rises and escapes near the top of the house, pulling cold air in down low. The colder the spell, the stronger this stack effect - and the more heat a leaky home loses.
Remodel threshold
Remodels and alterations to existing homes are held to a more achievable 5.0 ACH50, recognizing that older assemblies are harder to seal than new framing.
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.
Trusted for Blower Door Testing Arlington MA
Dominic did an excellent job guiding me through the HERS rating process, and it's clear he genuinely had my best interests in mind.
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!
I worked with this HERS rating company in South Boston on a remodel project and was able to get back 30,000 in rebates.
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 Arlington 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.
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.
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.
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.
Where do most leaks occur?
Common culprits are rim joists, top plates, attic hatches, recessed lights, plumbing and wiring penetrations, and gaps around windows and doors.
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.
Get Started With Blower Door Testing Arlington MA
Book a certified blower door test and get a permit-ready air-tightness report. Call 617-501-6788.
HERS Ratings Across Arlington and Nearby Communities
Home Energy Efficiency Consultants rates new homes, additions, and major renovations throughout Arlington — from Arlington Center, East Arlington, and Arlington Heights to Brackett and Morningside. Every Arlington project is filed with the Town of Arlington Inspectional Services 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 Arlington, including Cambridge, Somerville, Medford, Belmont, and Winchester. 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 Arlington rating on the schedule.
Arlington Specialized Energy Code — HERS Index Targets
Arlington enforces the Massachusetts Specialized (Opt-In) Energy Code. The required HERS score depends on fuel type and project scope — a lower index is stricter. As a fossil-fuel-free community, new construction in Arlington must be built all-electric, so the all-electric columns apply.
| Project type | Mixed-fuel | Mixed-fuel + solar | All-electric | All-electric + solar |
|---|---|---|---|---|
| New construction | HERS 42 | 42 | 45 | 45 |
| New construction — embodied-carbon credit | 45 | 45 | 48 | 48 |
| Accessory dwelling unit (ADU) | 52 | 55 | 55 | 58 |
| Major alteration / renovation / change of use | 65 | 70 | 70 | 75 |
A HERS rating is triggered by new construction, additions over 1,000 sq ft (or more than 100% of the existing conditioned area), and Level 3 alterations over 1,000 sq ft affecting more than 50% of the home. New homes must also pass a blower-door test at 3.0 ACH50 and include electrification-ready wiring for heat pumps, EV charging, and solar. We model your Arlington project up front so you know the exact target and the fastest path to hit it — call (617) 501-6788.
More Massachusetts Towns We Serve
Certified HERS ratings, blower door testing and energy code compliance across all 351 Massachusetts cities and towns.
