Certified HERS Rater serving Downtown Boston — helping residential high-rise developers, condo converters & owners meet the City of Boston Specialized Opt-in Stretch Energy Code and qualify for Mass Save incentives.
Get a Free QuoteCall 617-584-1809Downtown Boston 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.
Related Downtown Boston services: 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.

Yes. Downtown Boston 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.
New homes in Downtown Boston 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.
Downtown Boston 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.
These are the official maximum HERS Index scores that apply to projects in Downtown Boston 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.
Beyond the HERS maximums above, every new dwelling in Downtown Boston 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:
Passive House alternative (R405): Phius or PHI certification satisfies the code in Downtown Boston 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 Downtown Boston.
Detail sourced from the 2025 Massachusetts Stretch & Specialized Codes Technical Guidance (DOER, Sept 2025), Table R406.5 and Appendix RC.
HERS Rating Company provides certified HERS Index ratings across Downtown Boston, the dense core that blends the Financial District’s towering skyscrapers and Downtown Crossing with mid-1800s brick rowhouses and more than 15,000 dwellings. As historic buildings are converted to residences and new residential towers rise, Downtown’s housing mix is both old and brand-new. In climate zone 5A, our RESNET-accredited raters deliver fast, accurate energy ratings across this range while keeping projects compliant with Boston’s energy code.
Whether you are converting a historic office building near Downtown Crossing into condos or rating a new residential high-rise in the Financial District, our certified HERS raters provide every document the City of Boston Inspectional Services Department requires for permits and final inspections.
Boston has adopted the Specialized Opt-in Stretch Energy Code (225 CMR Ch. 22), built on IECC 2021, requiring new construction and major renovations to be verified by a certified HERS rater. Downtown Boston projects must meet air-tightness targets confirmed by blower door testing and duct leakage testing — critical for large multifamily towers and adaptive-reuse conversions alike. We provide all documentation required by the City of Boston Inspectional Services Department.
Ready to schedule your HERS rating in Downtown Boston? Get a fast, free quote today.
Schedule Your HERS RatingCall 617-584-1809HERS Rating costs in Downtown Boston typically depend on home size, design complexity, and the number of required site visits. For an accurate quote tailored to your Downtown Boston project, call our RESNET-certified team at 617-584-1809.
Yes. New residential construction in Downtown Boston, MA must demonstrate energy-code compliance, and a HERS Rating is the standard path under the Massachusetts Stretch Code. Call 617-584-1809 to confirm requirements for your build.
A HERS Rating in Downtown Boston generally involves plan review, a mid-construction inspection, and a final test with blower door and duct testing. Timing depends on your construction schedule. Reach us at 617-584-1809 to coordinate.
The Massachusetts Stretch Code sets maximum HERS index targets that vary by code version and home type, with lower scores indicating greater efficiency. Our Downtown Boston raters help you hit the required score—call 617-584-1809.
At HERS Rating Company, we are committed to providing the highest quality energy consulting services to homebuilders, architects, and developers across Massachusetts.
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