Blower Door Testing in Dennis, MA — Stretch Code HERS 42/45
RESNET and BPI-certified blower door air leakage testing for new construction, Mass Save programs, and MA Stretch Code compliance in Dennis, MA.
2026 Massachusetts Energy Code Facts — Dennis
Dennis enforces the Massachusetts Stretch Energy Code (225 CMR 22), adopted effective 7/1/2019. Under the 2025 code update (current for 2026 permits), new homes in Dennis 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 7/1/2019) — 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. New homes in Massachusetts (Climate Zone 5) must test at or below 3.0 ACH50 on the blower door test.
- 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 Dennis services: HERS Rating Dennis · Duct Leakage Testing Dennis · Stretch Code Compliance Dennis · 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 Dennis Energy Code
Do I need a HERS rating for a new home in Dennis?
Yes. Dennis has enforced the Massachusetts Stretch Energy Code since 7/1/2019, 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 is the maximum HERS score allowed in Dennis?
Homes permitted in Dennis 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.
What building energy code is Dennis on right now?
Dennis 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 Dennis 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 Dennis
Beyond the HERS maximums above, every new dwelling in Dennis 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 Dennis 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 Dennis.
Detail sourced from the 2025 Massachusetts Stretch & Specialized Codes Technical Guidance (DOER, Sept 2025), Table R406.5 and Appendix RC.
Professional Blower Door Testing Services in Dennis, Massachusetts
RESNET and BPI-certified blower door air leakage testing for new construction, Mass Save programs, and MA Stretch Code compliance in Dennis, MA. We measure air infiltration in CFM50 and ACH50 — the standard metrics required for Stretch Code compliance.
New construction in Dennis must achieve 3.0 ACH50 or less under the MA Stretch Code. Our certified test results are accepted by all Massachusetts building departments, utilities, and Mass Save program administrators.
Our Blower Door Testing Process in Dennis
- Free Quote: Contact us for a transparent quote for blower door testing in Dennis. Package pricing with HERS Rating available.
- Schedule Test: We schedule at a time convenient for your construction timeline — including intermediate tests during framing.
- On-Site Testing: Our certified technician installs the blower door fan and records CFM50 and ACH50 measurements.
- Report Delivery: Certified blower door report delivered within 24 hours — ready for permits, Mass Save, and HERS Rating.
Related Services in Dennis
HERS Rating in Dennis
Blower door testing is included in every HERS Rating.
Learn More →
Duct Leakage Testing in Dennis
Often scheduled together to minimize mobilization costs.
Learn More →
MA Stretch Code in Dennis
Full IECC 2021 compliance — blower door is required at 3.0 ACH50.
Learn More →
Frequently Asked Questions — Blower Door Testing in Dennis
How much does blower door testing cost in Dennis, MA?
Blower door testing pricing in Dennis: Single-family homes $1,850–$2,500 (when combined with HERS Rating) · Standalone blower door tests start from $1,850. Contact us for a free quote — package pricing available when combined with duct leakage testing and HERS Rating.
What is the blower door requirement in Dennis?
New residential construction in Dennis under the MA Stretch Code must achieve 3.0 ACH50 or less. The IECC 2021 base code requires 5.0 ACH50 or less.
How long does a blower door test take in Dennis?
The on-site blower door test in Dennis takes 1–2 hours. We deliver your certified test report within 24 hours.
Is blower door testing required for Mass Save rebates?
Yes. Blower door testing is required for Mass Save air sealing and insulation rebates in Dennis. Our certified results are accepted by all Mass Save program administrators.
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Also Serving Nearby Cities
We provide Blower Door Testing services throughout the region. Nearby cities we serve: Yarmouth · Barnstable · Brewster · Harwich