Duct Leakage Testing in Bellingham, MA — Stretch Code HERS 42/45
RESNET-certified duct leakage (duct blaster) testing for new construction, HERS Ratings, Mass Save programs, and MA Stretch Code compliance in Bellingham, MA.
2026 Massachusetts Energy Code Facts — Bellingham
Bellingham enforces the Massachusetts Stretch Energy Code (225 CMR 22), adopted effective 1/1/2020. Under the 2025 code update (current for 2026 permits), new homes in Bellingham must reach a maximum HERS Index of 42 (mixed-fuel) or 45 (all-electric) — up to 48 with qualifying credits — verified by a RESNET-certified HERS rater. ADUs must meet HERS 52–58, and major alterations, additions or change-of-use projects HERS 65–75, depending on fuel type and on-site solar.
- Energy code status: Stretch Code (effective 1/1/2020) — 1 of 242 MA municipalities (as of the June 2026 Mass.gov adoption list).
- Required testing & verification: blower door (air infiltration) testing, duct leakage testing, balanced mechanical ventilation (ERV/HRV), plus EV-ready and solar-ready provisions on the HERS compliance path. Under IECC 2021, total duct leakage may not exceed 4 CFM25 per 100 sq ft of conditioned floor area.
- Mass Save® 2026 new-construction incentives: up to $25,000 per all-electric single-family home (Passive House tier; $7,500 base tier, $15,000 ENERGY STAR® NextGen tier — HERS ≤45), up to $40,000 for a 4-unit building, up to $3,750/unit for 5+ unit multifamily, and up to $30,000 for major all-electric renovations. Every tier requires enrollment and verification by an approved HERS rating company.
Related Bellingham services: HERS Rating Bellingham · Blower Door Testing Bellingham · Stretch Code Compliance Bellingham · MA Energy Codes Guide — or get a free quote from our RESNET-certified team (617-584-1809).
Sources: 2025 DOER Massachusetts Stretch & Specialized Codes Technical Guidance (Sept 2025); Mass.gov Building Energy Code Adoption by Municipality (June 2026); Mass Save 2026 Residential New Construction program.
Common Questions About the Bellingham Energy Code
Do I need a HERS rating for a new home in Bellingham?
Yes. Bellingham has enforced the Massachusetts Stretch Energy Code since 1/1/2020, so new dwellings need a certified HERS rating from a RESNET-accredited rater — with blower door and duct leakage testing — before the certificate of occupancy.
What HERS index do new homes in Bellingham need to hit?
Homes permitted in Bellingham today must score HERS 42 or lower (mixed-fuel) or HERS 45 or lower (all-electric), up to 48 with qualifying credits. ADUs fall in the HERS 52–58 range and major alterations/additions in the 65–75 range, depending on fuel type and on-site solar.
Is Bellingham a Stretch Code or Specialized Code community?
Bellingham is one of 242 of Massachusetts’ 351 municipalities enforcing the Stretch Energy Code (225 CMR 22) per the June 2026 Mass.gov adoption list; 60 towns have gone further to the Specialized Code and 49 remain on the Base Code.
Official Maximum HERS Index Scores (Table R406.5)
These are the official maximum HERS Index scores that apply to projects in Bellingham under Table R406.5 of the current code (2025 DOER Technical Guidance):
| Building type | New construction (permits after 7/1/2024) | New construction w/ embodied-carbon credit (R406.5.2) | Accessory Dwelling Units | Major alterations, additions, change of use |
|---|---|---|---|---|
| Mixed-fuel building | 42 | 45 | 52 | 65 |
| Mixed-fuel + solar electric | 42 | 45 | 55 | 70 |
| All-electric building | 45 | 48 | 55 | 70 |
| All-electric + solar electric | 45 | 48 | 58 | 75 |
Scores are measured before counting on-site renewable generation (per R406.5). Historic buildings may opt out for alterations under R503.1.1. Embodied-carbon credits (+3 points) come from low-GWP concrete and insulation EPDs per Table R406.5.3/R406.5.4.
Complete Stretch Code Compliance Requirements in Bellingham
Beyond the HERS maximums above, every new dwelling in Bellingham on the HERS pathway must satisfy four code sections — R403.6 (Ventilation), R404.4 (EV Ready), R406 (HERS) and Appendix RB (Solar Ready) — per the 2025 DOER Technical Guidance:
- Balanced mechanical ventilation (R403.6): an ERV or HRV system meeting minimum system airflow, heat/energy-recovery efficiency, fan sound ratings and regulated air-inlet and exhaust locations — verified by field testing.
- EV-Ready parking (R404.4): pre-wiring with a connection point and dedicated electrical panel capacity for future vehicle charging.
- Solar-Ready roof (Appendix RB): a dedicated solar zone with structural-load verification, an electrical interconnection pathway and reserved panel space — unless the project installs solar directly.
- Air-tightness & duct sealing: blower door result of 3.0 ACH50 or lower (Climate Zone 5) and duct leakage within 4 CFM25 per 100 sq ft.
Passive House alternative (R405): Phius or PHI certification satisfies the code in Bellingham in place of a HERS score — with a Certified Passive House Consultant for design and a Phius Certified Verifier/Rater during construction — and still requires EV-Ready and Solar-Ready compliance. Prescriptive path: allowed only for buildings without individually separate dwelling units, additions, and alterations — and a whole-building prescriptive project must implement 2 of the 3 additional-efficiency packages in R408 (enhanced envelope, higher-efficiency HVAC, or reduced water-heating energy). Additions of 1,000 sq ft or more (or exceeding 100% of the existing floor area) must meet both R502.3 prescriptive and the R406.5 HERS limits. Level III alterations (work area over 50% of the home and over 1,000 sq ft) also trigger HERS compliance; historic buildings are exempt under R501.6. Note that ENERGY STAR® is no longer a compliance path — HERS and Passive House are the two certification routes in Bellingham.
Detail sourced from the 2025 Massachusetts Stretch & Specialized Codes Technical Guidance (DOER, Sept 2025), Table R406.5 and Appendix RC.
Professional Duct Leakage Testing Services in Bellingham, Massachusetts
RESNET-certified duct leakage testing for new construction, HERS Ratings, Mass Save programs, and MA Stretch Code compliance in Bellingham, MA. We measure total duct leakage and leakage to outdoors — the two metrics required by all Massachusetts energy codes.
New construction in Bellingham with forced-air HVAC must achieve total duct leakage of 4% or less of system airflow under the MA Stretch Code. Our certified reports are accepted by all Massachusetts building departments and Mass Save administrators.
Our Duct Leakage Testing Process in Bellingham
- Free Quote: Contact us for a transparent quote for duct testing in Bellingham. Package pricing with HERS Rating available.
- Schedule Test: We schedule your duct blaster test at a convenient time — including pre-drywall tests.
- On-Site Testing: Our technician connects the duct blaster fan and records total leakage and leakage-to-outside.
- Report Delivery: Certified duct leakage report delivered within 24 hours — ready for permits, Mass Save, and HERS Rating.
Related Services in Bellingham
HERS Rating in Bellingham
Duct leakage testing is included in every HERS Rating.
Learn More →Blower Door Testing in Bellingham
Often scheduled together to minimize mobilization costs.
Learn More →MA Stretch Code in Bellingham
Full compliance: HERS 55, ACH50 3.0, duct leakage 4%.
Learn More →Frequently Asked Questions — Duct Leakage Testing in Bellingham
How much does duct leakage testing cost in Bellingham, MA?
Duct leakage testing pricing in Bellingham: Single-family homes $1,850–$2,500 (when combined with full HERS Rating package) · Standalone duct tests start from $250. Contact us for a free quote — package pricing available with blower door testing and HERS Rating.
What is the duct leakage limit in Bellingham?
Under the MA Stretch Code, total duct leakage in Bellingham must be 4% or less of system airflow. The IECC 2021 base code allows up to 8%. Leakage-to-outside must be 4 CFM25 per 100 sq ft under both codes.
How long does duct leakage testing take in Bellingham?
The on-site duct blaster test in Bellingham takes 1–2 hours. We deliver your certified report within 24 hours.
Is duct leakage testing required in Bellingham?
Yes. Duct leakage testing is required for new residential construction with forced-air HVAC in Bellingham under both the MA Stretch Code and IECC 2021 base code, and as a component of every HERS Rating.
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