Massachusetts Stretch Energy Code Mattapan, MA
Expert Massachusetts Stretch Energy Code compliance services in Mattapan, MA. RESNET-certified HERS raters helping builders meet IECC 2021 requirements and obtain certificates of occupancy.
Get Compliance Help Call 617-584-18092026 Massachusetts Energy Code Facts — Mattapan
Mattapan enforces the Municipal Opt-in Specialized Energy Code (225 CMR 23), effective 1/1/2024 — one of only 60 Massachusetts municipalities to adopt it (a Stretch Code community since 7/1/2011). For 2026 permits, new homes 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: Specialized Opt-in Code (adopted 1/1/2024) — 1 of 60 MA municipalities (as of the June 2026 Mass.gov adoption list).
- Specialized Code requirements in Mattapan: new multifamily buildings over 12,000 sq ft must be Passive House certified; all-electric homes must use heat pumps for heating and hot water; homes that keep fossil fuels need electrification pre-wiring and rooftop solar, and fossil-fuel homes over 4,000 sq ft must certify net-zero (HERS 0).
- 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.
- 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 Mattapan services: HERS Rating Mattapan · Blower Door Testing Mattapan · Duct Leakage Testing Mattapan · 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 Mattapan Energy Code
Do I need a HERS rating for a new home in Mattapan?
Yes. Mattapan follows the Municipal Opt-in Specialized Energy Code (effective 1/1/2024) on top of the Stretch Code it adopted in 7/1/2011. New dwellings need a certified HERS rating from a RESNET-accredited rater before the certificate of occupancy.
What HERS score is required in Mattapan?
New homes in Mattapan must score HERS 42 or lower (mixed-fuel) or HERS 45 or lower (all-electric) — up to 48 with qualifying credits. Fossil-fuel homes over 4,000 sq ft must certify net-zero (HERS 0), and multifamily over 12,000 sq ft needs Passive House certification.
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Mattapan is one of only 60 of Massachusetts’ 351 municipalities on the Specialized Opt-in Code (225 CMR 23) per the June 2026 Mass.gov adoption list — the state’s most stringent energy code tier.
Official Maximum HERS Index Scores (Table R406.5)
These are the official maximum HERS Index scores that apply to projects in Mattapan 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 Mattapan
Beyond the HERS maximums above, every new dwelling in Mattapan 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 Mattapan 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 Mattapan.
Mattapan’s Specialized Code: Three Ways to Comply (Appendix RC)
- Zero Energy Pathway (RC102): certify HERS 0 or lower — the home produces as much energy as it uses. Before counting on-site solar, the design must still score ≤45 (all-electric) or ≤42 (mixed-fuel) and meet IECC 2021 envelope U-factors. Alternative: Passive House plus a Phius ZERO design certification — the only Specialized option that can credit off-site renewable energy.
- All-Electric Pathway (RC103) — the most common route in Mattapan: comply with the R408.2 HVAC and water-heating efficiency packages (electric-resistance primary heating is excluded — heat pumps required), meet EV-Ready and Solar-Ready, then either achieve a final certified HERS of 45 or less without on-site power (with ERV/HRV, R406.2 lighting, and base-code U-factors) or pre-certify to Phius CORE / PHI. With load-management design, most all-electric homes run on a standard 200-amp panel.
- Mixed-Fuel Pathway (RC104) — only for dwellings under 4,000 sq ft: score HERS 42 or less without on-site power, plus electric-readiness (RC104.3), on-site renewables (RC104.4/RC105) and EV-Ready — or pre-certify Passive House with electric readiness. Electric readiness in Mattapan means a 250-volt/40-amp outlet within 3 feet of any gas or propane range, a 250-volt/30-amp outlet within 3 feet of the clothes dryer, a reserved branch circuit for a future heat-pump heating system, and a heat-pump water-heater location with 7-foot clearance.
Detail sourced from the 2025 Massachusetts Stretch & Specialized Codes Technical Guidance (DOER, Sept 2025), Table R406.5 and Appendix RC.
MA Stretch Energy Code Compliance in Mattapan
HERS Rating Company provides comprehensive Massachusetts Stretch Energy Code compliance services in Mattapan, MA. Our RESNET-certified HERS raters guide builders, developers, and contractors through the full IECC 2021 compliance process — from energy modeling to final certification.
The Massachusetts Stretch Energy Code applies to all new residential construction and major renovations in Mattapan and most Massachusetts municipalities. Non-compliance can delay or prevent your certificate of occupancy. Our team ensures your project meets every requirement, on schedule.
What Is the Massachusetts Stretch Energy Code?
The Massachusetts Stretch Energy Code is an optional appendix to the base Massachusetts energy code that sets higher performance standards for buildings. Since its adoption, the Stretch Code has become mandatory in most Massachusetts communities — including Mattapan — and is based on IECC 2021 with Massachusetts amendments.
The Stretch Code requires third-party verification by a certified HERS rater for all new residential construction. Key requirements include: maximum air leakage of 3.0 ACH50, duct leakage limits, minimum HERS Index scores, and mandatory blower door and duct leakage testing.
MA Stretch Code Requirements in Mattapan
- HERS Rating Required — Third-party HERS certification by a RESNET-accredited rater
- Blower Door Test — Maximum 3.0 ACH50 air leakage at 50 Pascals
- Duct Leakage Test — Maximum 4 CFM25 per 100 sq ft of conditioned floor area
- Energy Modeling — REM/Rate or equivalent software used to verify compliance
- Insulation Verification — Confirmed R-values for walls, roof, and foundation
- Window Performance — U-factor and SHGC requirements per IECC 2021
- Mechanical Ventilation — Balanced ventilation system verification
Our Stretch Code Compliance Services in Mattapan
- Pre-construction energy modeling and compliance review
- HERS Index rating and certification
- Blower door air tightness testing
- Duct leakage and duct tightness testing
- Pre-drywall and final on-site inspections
- Complete documentation package for Mattapan building department
- Certificate of occupancy support and follow-up
Why Choose HERS Rating Company for Stretch Code in Mattapan?
We specialize exclusively in Massachusetts energy code compliance. Our team has helped hundreds of builders in Mattapan and across Massachusetts navigate the Stretch Code process efficiently. We understand exactly what Mattapan’s building department needs, and we deliver complete, accurate documentation every time.
We also help identify opportunities to improve energy performance beyond minimum code requirements — helping your Mattapan clients qualify for Mass Save rebates and green building certifications like Energy Star and Zero Energy Ready Home.
Need Stretch Energy Code compliance help in Mattapan, MA? Contact our experts today.
Get a Free Consultation Call 617-584-1809Related Services in Mattapan
HERS Rating Mattapan MA | Blower Door Testing Mattapan MA | Duct Leakage Testing Mattapan MA