What HERS Score Is Required in Boston?
If you are building a new home, adding an ADU, renovating an existing property, or converting a building to residential use in Boston, knowing the required HERS score early can save time, money, and permit headaches.
Boston projects commonly follow the Massachusetts Stretch Energy Code and Specialized Code pathways, and the exact HERS target depends on building type, fuel type, and whether the project is new construction, multifamily, or existing-building work.
Boston HERS Score Requirements Explained
A HERS score, or Home Energy Rating System score, is a measurement of a building’s projected energy performance. Lower numbers are better. In Boston, the allowed HERS score depends on whether the home is all-electric or mixed-fuel, whether it is an ADU, and whether the project is new construction, multifamily, or a major alteration, addition, or change of use.
That is why it is so important to review the code path and the HERS model before equipment is ordered. HVAC systems, ventilation systems, insulation levels, windows, and water heating all affect whether the project will meet the required target.
What HERS Score Is Required in Boston?
Boston projects typically follow the Massachusetts Stretch Energy Code / Specialized Code pathways, and the required HERS score depends on whether the project is all-electric, mixed-fuel, an ADU, a major renovation, or a multifamily building.
All-Electric New Construction
For new construction dwelling units under the residential stretch pathway, all-electric buildings are capped at HERS 45.
Code Reference: R406.5
Mixed-Fuel New Construction
For new construction dwelling units under the residential stretch pathway, mixed-fuel buildings are capped at HERS 42.
Code Reference: R406.5
Accessory Dwelling Units (ADUs)
ADUs are allowed higher HERS caps than standard new construction dwelling units under the same stretch and specialized code framework.
Code References: R406.5, RC102, RC103, RC104
Major Renovations, Additions, or Change of Use
Major alterations, additions, and change-of-use projects can have higher permitted HERS scores than new construction. Mixed-fuel existing-building work may be around HERS 65, while solar-electric or all-electric combinations can reach the 70 to 75 range depending on the exact pathway.
Code Reference: R406.5
Multifamily Buildings
58 / 55 major alterations
Multifamily and mixed-use buildings using the commercial HERS path follow a separate table from low-rise residential projects. New construction is generally 45 all-electric and 42 mixed-fuel. Major alterations or change of use are generally 58 all-electric and 55 mixed-fuel.
Code Reference: C407.4
Boston HERS Code References
R406.5 — Residential Stretch Energy Code ERI/HERS pathway, including new construction, ADUs, and existing-building project categories.
C407.4 — Commercial / multifamily stretch HERS pathway for multifamily and mixed-use buildings.
RC102 — Zero Energy Pathway.
RC103 — All-Electric Pathway.
RC104 — Mixed-Fuel Pathway.
These sections are the code references commonly used for the HERS limits summarized above.
Important Note
The exact HERS target can still vary based on building classification, permit date, project scope, solar, embodied carbon credit, and whether the project is being reviewed under residential or multifamily/commercial provisions. For that reason, multifamily and change-of-use projects should always be modeled and reviewed before equipment is ordered.
Massachusetts HERS Reference Chart
Use this chart as a quick reference for the HERS caps commonly discussed for Massachusetts code pathways.
Why Boston Projects Need HERS Planning Early
Avoid Ordering the Wrong Equipment
HVAC systems, water heaters, windows, and ventilation equipment all affect whether the project matches the energy model.
Keep Permits Moving
Preliminary HERS support helps many projects move through permit review with fewer surprises.
Reduce Expensive Redos
Catching issues before installation is usually far easier than fixing them after the job is already in progress.
Common Boston Project Types
- New construction homes
- Multifamily buildings
- Triple-decker renovations
- ADUs and detached accessory units
- Additions and major alterations
- Whole-house renovations
- Commercial to residential conversions
- Permit-stage preliminary HERS reports
Boston Neighborhoods We Serve
We provide HERS ratings, energy code compliance, blower door testing, duct leakage testing, and permit support throughout Boston, including Allston/Brighton, Back Bay, Beacon Hill, Charlestown, Chinatown, Dorchester, East Boston, Fenway/Kenmore, Jamaica Plain, Mission Hill, North End, Roslindale, Roxbury, South Boston, South End, West End, West Roxbury, Bay Village, Downtown/Financial District, Fort Point/Seaport, Hyde Park, Longwood, and Mattapan.
We provide HERS ratings and energy code compliance throughout all Boston neighborhoods, helping projects meet stretch code requirements and pass inspection the first time.
Allston/Brighton
Allston/Brighton is known for students, young professionals, and a busy housing market. Renovation and rental property projects here often need HERS ratings and energy code compliance.
Back Bay
Back Bay is known for Victorian brownstones and historic homes. Projects here often require HERS ratings and energy code compliance for renovations, additions, and multifamily buildings.
Beacon Hill
Beacon Hill is a historic neighborhood with older rowhouses and tight urban conditions. Many projects here need HERS ratings and careful energy code planning to improve efficiency.
Charlestown
Charlestown includes historic homes and dense residential areas. Many projects require HERS ratings and energy code compliance for additions, renovations, and multifamily work.
Chinatown
Chinatown is a dense urban neighborhood near downtown Boston. Projects here often need HERS ratings, ventilation planning, and energy code compliance to stay on track.
Dorchester
Dorchester features many multifamily and triple-decker homes. These projects commonly require HERS ratings, ERV systems, and energy code compliance to pass inspection.
East Boston
East Boston includes waterfront homes, multifamily buildings, and active residential development. New construction and renovation projects here often need HERS ratings and code support.
Fenway/Kenmore
Fenway/Kenmore has a heavy student population and a mix of residential buildings. Projects here often require HERS ratings and energy code compliance for upgrades and renovations.
Jamaica Plain
Jamaica Plain has a mix of older homes and renovation projects. Achieving compliance often requires HERS ratings, upgraded insulation, and efficient HVAC systems.
Mission Hill
Mission Hill is known for triple-deckers and dense residential blocks. Projects here often require HERS ratings, air sealing, ventilation upgrades, and energy code compliance.
North End
North End has tight streets, older buildings, and compact urban lots. Renovation projects here often need HERS ratings and careful energy code planning before work begins.
Roslindale
Roslindale has many residential additions and renovation projects. Homeowners here often benefit from early HERS ratings and energy code guidance before equipment is selected.
Roxbury
Roxbury includes new construction and redevelopment activity. These projects often need HERS ratings and energy code compliance to stay efficient and permit-ready.
South Boston
South Boston has a mix of new construction and renovations. Many projects require HERS ratings, energy modeling, and code compliance to meet Boston stretch energy code requirements.
South End
South End is known for brownstones and renovation work. Projects here often need HERS ratings and energy code support to balance older buildings with modern efficiency targets.
West End
West End includes dense urban residential projects near downtown. Many jobs here require HERS ratings and energy code compliance to keep permitting and construction moving smoothly.
West Roxbury
West Roxbury has many residential renovations, additions, and new homes. These projects often require HERS ratings and code-compliant equipment planning from the start.
Bay Village
Bay Village is a compact historic neighborhood with older building stock. Projects here often need HERS ratings and practical energy code solutions for tight spaces.
Downtown/Financial District
Downtown and the Financial District are becoming more residential. Conversion and mixed-use projects here often need HERS ratings and careful code-path review.
Fort Point/Seaport
Fort Point and Seaport feature newer waterfront development and higher-end residential work. These projects often require HERS ratings and energy code compliance.
Hyde Park
Hyde Park includes many single-family and residential renovation projects. These jobs often need HERS ratings and early code guidance before systems are ordered.
Longwood
Longwood is a dense medical and academic area with nearby residential projects. These jobs often require HERS ratings and careful mechanical planning for energy code compliance.
Mattapan
Mattapan is a diverse residential neighborhood with many renovation and addition projects. These often require HERS ratings and efficient system planning to meet code.
Boston HERS Score FAQ
What HERS score do I need for an all-electric home in Boston?
For new construction under the residential stretch pathway, all-electric dwelling units are generally capped at HERS 45.
What HERS score do I need for a mixed-fuel home in Boston?
For new construction under the residential stretch pathway, mixed-fuel dwelling units are generally capped at HERS 42.
What HERS score is required for an ADU in Boston?
ADUs are generally capped at HERS 55 for all-electric and HERS 52 for mixed-fuel under the stretch and specialized code framework.
What HERS score is required for renovations or additions in Boston?
Major alterations, additions, and some change-of-use projects can fall in a higher HERS range, often around 65 to 75 depending on the exact pathway and configuration.
What HERS score is required for multifamily projects in Boston?
For multifamily projects using the commercial HERS pathway, new construction is generally capped at HERS 45 for all-electric and HERS 42 for mixed-fuel, while major alterations or change-of-use projects may be capped at HERS 58 for all-electric and HERS 55 for mixed-fuel.
Helpful Boston Service Pages
Boston HERS Rating
Need a Boston HERS rater for your project? Visit our dedicated Boston HERS rating page for direct help with preliminary and final reports.
Boston Energy Code Help
Need help understanding what your project needs to pass code? Visit our Boston energy code help page for support.
Serving Boston from Greater Boston
We work with projects throughout Boston and surrounding communities and provide responsive help for homeowners, builders, developers, and architects.
Code Reference Summary
The HERS values on this page are based on the Massachusetts code summary for residential stretch, multifamily/commercial stretch, and specialized code pathways. Residential stretch code R406.5 includes 42 for mixed-fuel new construction, 45 for all-electric new construction, 52 for mixed-fuel ADUs, 55 for all-electric ADUs, and roughly 65 to 75 for major alterations, additions, or change of use depending on configuration. Multifamily commercial path C407.4 includes 42 mixed-fuel and 45 all-electric for new construction, plus 55 mixed-fuel and 58 all-electric for major alterations or change of use. The specialized code sections RC102, RC103, and RC104 repeat the all-electric, mixed-fuel, and ADU caps used in those pathways.
Need Help With a Boston HERS Rating Project?
We help with HERS ratings, preliminary reports, energy code compliance, blower door testing, duct leakage testing, and project support throughout Boston.
