REScheck & COMcheck Lexington MA - Quick Facts
Local energy code in Lexington
- As of January 1, 2024, Lexington enforces the Massachusetts Specialized (Opt-In) Energy Code on top of the Stretch Code baseline - IECC Climate Zone 5A.
- The Opt-In code goes further than the Stretch baseline: new fossil-fuel homes must be pre-wired for electrification and include on-site solar where roof space allows.
- New all-electric homes rely on heat pumps for heat and hot water; large fossil-fuel homes over 4,000 sq ft must hit net-zero (HERS 0), and multifamily over 12,000 sq ft must be Passive House.
- Lexington also participates in the Massachusetts Municipal Fossil Fuel-Free Building Demonstration Program - new construction and major renovations must be built fossil-fuel-free (all-electric), a step beyond the Specialized Code.
REScheck & COMcheck in Lexington
- REScheck documents the prescriptive residential path for Lexington additions, alterations and renovations (from $300); new-construction performance projects use a full HERS energy model instead.
- Commercial projects use COMcheck for the prescriptive path (from $600); larger new commercial buildings need third-party performance certification under the Stretch Code.
- 24-48 hour turnaround - documentation ready to upload with your Lexington permit application.
Mass Save rebates for Lexington (2026)
- All-electric renovations and additions can earn Mass Save incentives up to $20,000 (Level 1) or $30,000 (Level 2) for a single-family home, verified by a RESNET-certified HERS rater.
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REScheck & COMcheck Lexington MA
Fast, accurate REScheck and COMcheck energy code compliance reports for residential and commercial projects in Lexington, Massachusetts. We prepare the documentation your building department needs to issue a permit — without the cost of a full performance-path energy rating when your project does not require one.
What we deliver
A signed compliance report matched to your plans and ready to upload with your Lexington building permit application.
What Is a REScheck and What Is a COMcheck?
These are the two standard software tools plan reviewers accept for energy code compliance. Developed by the DOE, they let a Middlesex County project demonstrate that its envelope (and, for commercial, lighting and mechanical) meets the IECC.
What is a COMcheck?
COMcheck handles commercial work and high-rise residential of four stories or more. The DOE tool evaluates envelope, lighting (interior and exterior), and mechanical systems against either the IECC or ASHRAE 90.1, with trade-offs allowed across components.
What is a REScheck?
For homes, REScheck is the go-to. This DOE program checks residential envelopes — detached houses and multifamily up to three stories — and allows insulation and fenestration trade-offs to show prescriptive or component-based IECC compliance.
REScheck Projects in Lexington
REScheck is the simplest path for smaller residential projects in Lexington that do not need a HERS rating. It is typically the right tool for:
- New residential construction or an addition of 1,000 sq ft or less that does not require a HERS rating
- Window and insulation upgrades that must be documented for a building permit
- Projects where insulation and window trade-offs are enough to demonstrate compliance
- Permit applications needing residential envelope documentation on the prescriptive or UA trade-off path
- Detached accessory structures with conditioned space
Commercial Work That Needs a COMcheck in Lexington
COMcheck is required for commercial and larger projects in Lexington. Reach for a COMcheck when your project involves:
- High-rise residential buildings of four stories or more
- Tenant fit-outs and interior or exterior lighting alterations
- New mechanical (HVAC) or service water heating systems in commercial spaces
- Commercial buildings — offices, retail, restaurants, warehouses, and mixed-use
- Restaurant build-outs and retail white-box improvements
Inside Your REScheck or COMcheck Report
COMcheck report
The COMcheck Envelope, Lighting, and Mechanical Compliance Certificates plus the Plan Review Checklist — the full package a commercial plan reviewer expects for permit submission.
Plans matched to code
We enter your assemblies, fenestration, and (for commercial) lighting and mechanical details exactly as designed, so the report reflects what you are actually building in Lexington.
Fast, permit-ready turnaround
We deliver documentation ready to upload with your building permit application, and we answer plan-review questions if the department asks for revisions.
REScheck report
A signed REScheck compliance certificate matched to your plans, the inspection checklist, and the UA trade-off summary showing your insulation R-values and window U-factors meet the residential energy code.
Serving Lexington and Middlesex County
Lexington sits in Middlesex County, Massachusetts, in IECC climate zone 5A — the cold-climate zone that drives the insulation and air-sealing levels your REScheck or COMcheck must document. We prepare compliance reports for projects throughout Middlesex County, matched to the code edition Lexington currently enforces.
REScheck & COMcheck Pricing in Lexington
Transparent starting prices. Final cost depends on project size, number of assemblies, and scope.
- REScheck (residential): starting at $300
- COMcheck (commercial): starting at $600
- Revisions to match plan-review comments are handled promptly
REScheck reports start at $300 and COMcheck reports start at $600 for projects in Lexington. Send your plans for an exact quote.
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Which Energy Code Report Does a Lexington Project Need?
Lexington has adopted the Massachusetts Specialized Code (the municipal opt-in code, 225 CMR 22.00 Appendix RC for homes and 225 CMR 23.00 Appendix CC for commercial and multifamily). New homes must be built to the net-zero-ready Specialized paths, new homes over 4,000 sq ft must use the all-electric or zero-energy path, and new multifamily buildings over 12,000 sq ft must be Passive House certified.
| Your Lexington project | What the energy code paperwork usually is |
|---|---|
| New single-family home or low-rise residential building | A HERS rating or Passive House certification on a Specialized Code path. REScheck is not accepted for new homes. |
| Residential addition of 1,000 sq ft or less (and not over 100% of the existing home) | REScheck (REScheck-Web, 2023 Massachusetts Stretch Code) or the prescriptive tables |
| Residential addition over 1,000 sq ft or over 100% of the existing home | A HERS rating of the whole house (HERS 65 or lower mixed-fuel, 70 or lower all-electric) |
| Basement or attic conversion with no change to footprint or roofline | No HERS rating required; REScheck or prescriptive documentation |
| Residential renovation or alteration | Prescriptive alteration rules; REScheck can document the envelope. Large "extensive" alterations over 1,000 sq ft may need a HERS rating. |
| New commercial building up to 20,000 sq ft | COMcheck: Envelope, Lighting and Mechanical certificates plus the Plan Review Inspection Checklist |
| New commercial building over 20,000 sq ft | COMcheck Lighting and Mechanical, with the envelope shown by backstop and thermal-bridge calculations, on a performance path (Targeted Performance/TEDI or ASHRAE 90.1 Appendix G) or Passive House |
| Commercial addition, alteration, or lighting/HVAC change | COMcheck for the altered systems |
| Multifamily building over 12,000 sq ft | Passive House certification (Phius or PHI) |
Based on 225 CMR 22.00 and 23.00 (Massachusetts energy code, 2025 edition). Building departments make the final call, so we confirm the path for your project before we start. Lexington is in Middlesex County, served from our Somerville (519 Broadway) office.
How We Prepare Your Lexington REScheck or COMcheck
Send your plans
Email the permit set for your Lexington project. We tell you the same day whether you need a REScheck, a COMcheck or a HERS rating.
We model the building
We enter every assembly, window, light fixture and HVAC unit as designed and flag anything that fails before the plan reviewer sees it.
Permit-ready report
You get the signed compliance certificates and checklists, ready to upload with your Lexington building permit application.
Plan review support
If the building department asks for changes, we revise the report and answer the reviewer's questions.
REScheck & COMcheck for Lexington Permits
Lexington put the Specialized (Opt-In) Code into effect on January 1, 2024. It had been on the Stretch Code since January 1, 2011. The town runs its permitting on OpenGov, where building permit applications are routed for building, zoning, conservation and planning review.
Houses and additions
Most residential permits in Lexington fall into one of three groups:
- REScheck: small additions up to 1,000 sq ft that are not more than 100% of the existing home, and alterations where the prescriptive path is allowed.
- HERS rating for new homes: HERS 42 mixed-fuel or 45 all-electric.
- HERS rating for larger additions and major renovations: HERS 65 mixed-fuel or 70 all-electric.
A teardown-and-rebuild counts as a new home, so it needs a HERS rating, not a REScheck. Plan the HERS rating before framing starts so insulation and air sealing can be inspected at rough-in.
Hartwell Avenue and commercial work
COMcheck covers the envelope, lighting and mechanical systems of commercial buildings. A commercial building over 20,000 sq ft needs more than COMcheck under the Stretch and Specialized codes. That matters along Hartwell Avenue, where the Hartwell Labs office and R&D building has been designed near all-electric. At 7 Hartwell Avenue, a 130-apartment building with a small café was approved by the Planning Board in 2025 and financed in 2026, a mixed-use project that needs both residential and commercial energy documentation.
HEEC's Somerville office at 519 Broadway is the closest to Lexington. Send us your drawings and we will confirm which reports your permit needs.
REScheck & COMcheck Questions for Lexington Projects
Do I need a REScheck or a HERS rating in Lexington?
For a new home in Lexington, you need a HERS rating or Passive House, because Lexington is on the Specialized Code. REScheck is used for smaller additions (1,000 sq ft or less and not over 100% of the existing home), basement and attic conversions, and renovations.
When is a COMcheck required in Massachusetts?
A COMcheck documents commercial energy code compliance for new commercial buildings up to 20,000 sq ft (envelope, lighting and mechanical), for lighting and mechanical on larger buildings, and for commercial additions and alterations such as fit-outs, lighting changes and HVAC replacements. Massachusetts commercial code is based on the 2021 IECC with state amendments in 225 CMR 23.00.
What does a COMcheck include?
The COMcheck Envelope Compliance Certificate, the Interior and Exterior Lighting Compliance Certificates, the Mechanical Compliance Certificate, and the Plan Review Inspection Checklist. Massachusetts 225 CMR 23.00 Section C103.2 lists these as the construction-document requirements for buildings up to 20,000 sq ft.
What does a REScheck include?
A REScheck compares your home's envelope (insulation R-values and window U-values) to the code using a total UA trade-off, so stronger performance in one assembly can offset another. The report includes the compliance certificate and inspection checklist. Mandatory items such as air sealing and duct sealing still apply.
What size addition needs a HERS rating instead of REScheck?
In Massachusetts, a residential addition over 1,000 sq ft, or over 100% of the existing conditioned floor area, needs a HERS rating of the whole house (225 CMR 22.00 R502.1.1). Converting an existing basement or attic without changing the footprint or roofline does not.
What information do you need to prepare a REScheck or COMcheck?
Plans with wall, roof and floor sections, insulation types and R-values, the window and door schedule with U-factors and SHGC, and for commercial work the lighting fixture schedule with wattages, lighting controls, and HVAC and water heating equipment schedules.
Which software version is used in Massachusetts?
REScheck-Web with the 2023 Massachusetts Stretch Code option for residential, and COMcheck-Web set to the 2021 IECC (or ASHRAE 90.1-2019) for commercial, matching the code Massachusetts enforces.
How much does a REScheck or COMcheck cost in Lexington?
REScheck reports start at $300 and COMcheck reports start at $600. The final price depends on the size of the project and how many assemblies and systems need to be entered. Send your plans for an exact quote.
Do teardown rebuilds in Lexington need a HERS rating?
Yes. A rebuilt house is new construction, and Lexington has been on the Specialized (Opt-In) Code since January 1, 2024. New homes need a HERS rating (HERS 42 mixed-fuel or 45 all-electric) or Passive House. A REScheck only covers small additions and alterations where the prescriptive path is allowed.
Does a mixed-use project on Hartwell Avenue need REScheck or COMcheck?
Often both kinds of documentation. Apartments are residential and need a HERS rating or other residential compliance, while the commercial space (such as the café planned at 7 Hartwell Avenue) uses COMcheck. Commercial buildings over 20,000 sq ft in Lexington need more than COMcheck under the Specialized Code.
Related: HERS rating in Lexington · Blower door testing · COMcheck & REScheck reports
Need a REScheck or COMcheck in Lexington?
Send us your plans and we will tell you which report you need and get it back to you fast — ready for your Lexington permit.
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HERS Ratings Across Lexington and Nearby Communities
Home Energy Efficiency Consultants rates new homes, additions, and major renovations throughout Lexington — including Lexington Center, East Lexington, and Munroe. Every Lexington project is filed with the Town of Lexington Building Department, and we handle the energy model, blower door and duct leakage testing, and the compliance paperwork from start to finish.
We also serve the communities right around Lexington, including Arlington, Bedford, Burlington, Winchester, and Lincoln. Our Somerville office at 519 Broadway is the closest of our four Massachusetts locations — see our Somerville office or call (617) 501-6788 to get a Lexington rating on the schedule.
Lexington Specialized Energy Code — HERS Index Targets
Lexington enforces the Massachusetts Specialized (Opt-In) Energy Code. The required HERS score depends on fuel type and project scope — a lower index is stricter. As a fossil-fuel-free community, new construction in Lexington must be built all-electric, so the all-electric columns apply.
| Project type | Mixed-fuel | Mixed-fuel + solar | All-electric | All-electric + solar |
|---|---|---|---|---|
| New construction | HERS 42 | 42 | 45 | 45 |
| New construction — embodied-carbon credit | 45 | 45 | 48 | 48 |
| Accessory dwelling unit (ADU) | 52 | 55 | 55 | 58 |
| Major alteration / renovation / change of use | 65 | 70 | 70 | 75 |
A HERS rating is triggered by new construction, additions over 1,000 sq ft (or more than 100% of the existing conditioned area), and Level 3 alterations over 1,000 sq ft affecting more than 50% of the home. New homes must also pass a blower-door test at 3.0 ACH50 and include electrification-ready wiring for heat pumps, EV charging, and solar. We model your Lexington project up front so you know the exact target and the fastest path to hit it — call (617) 501-6788.
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