Arlington HERS 44 Zoning Exemption & Solar Rule

The HERS 44 Exemption for Energy Efficient Homes

Under Arlington Zoning Section 5.4.2.B(8), the minimum frontage and lot area rules do not apply to a home on an R0, R1 or R2 lot with an existing principal building if it is built to HERS 44 or lower (or the code maximum, if lower). That can make it possible to replace an older house on an undersized lot without a variance.

Written by Dominic Zammuto, RESNET-certified HERS Rater (#3385643) and Phius Certified Verifier, Multifamily Qualified (Phius ID 124235). Checked against Town of Arlington sources in November 2026. Zoning changes often, so confirm with the city or town before you design.

Item	What Section 5.4.2.B(8) says
Where	R0, R1 or R2 lots with an existing principal building
What it waives	The minimum frontage and lot area requirements
Energy standard	The lower of HERS 44, or the maximum HERS score in the Massachusetts energy code
When it applies	The new house is built within the existing foundation footprint, or with an addition that is not a Large Addition, or by special permit

How to Hit HERS 44

Arlington is a Specialized Code town

The code already asks new homes for HERS 42 mixed-fuel or 45 all-electric. An all-electric home has to beat its code target by a point to reach 44.

Tight construction

Air sealing is the cheapest HERS point. We blower door test at pre-drywall so leaks are fixed while they are easy to reach.

Heat pumps and ventilation

Efficient cold-climate heat pumps, an ERV and a heat pump water heater move the score the most.

Solar

Rooftop solar lowers the HERS score directly and is often the easiest way to close the last points.

See HERS ratings and blower door testing.

Solar Requirement for Larger Projects

Environmental Design Review projects also submit a LEED checklist with a narrative. HEEC does not do LEED; that part comes from your LEED consultant.

Item	What Section 6.4 says
Who	Projects that need Environmental Design Review by the Arlington Redevelopment Board, including six or more dwelling units, mixed-use, and sites on Massachusetts Ave, Pleasant St, Broadway and other listed streets
Solar	At least 50% of the roof area; parking structures need solar over 90% of the top level
Exemptions	No solar-ready zone or more than 50% shading; existing buildings without the structural capacity; historic district denials; change of use alone
Bonus	In the MBMF Overlay District, one extra story for LEED Gold certified or an equivalent green building standard approved by the Redevelopment Board

How We Help in Arlington

Check the rules before design is locked

We read the Arlington requirement against your plans early and pick the cheapest pathway that passes.

Energy modeling

We run a preliminary HERS rating from your plans and show the cheapest set of upgrades that reaches HERS 44, so you know the exemption works before you design around it.

Documents for permits and review

We prepare the energy code paperwork for the building department and the energy numbers your architect or permitting team needs. HEEC does not do LEED; if your project needs LEED, your LEED consultant handles that part.

Testing and verification

We do the inspections, blower door and duct leakage testing and final verification with our own crew as a RESNET HERS Rater and Phius Certified Rater and Verifier (Multifamily Qualified).

More: Net zero and Passive House rules in other Massachusetts cities · Phius Passive House verification · Multifamily HERS, ENERGY STAR and Phius

FAQ: Arlington HERS 44 Exemption and Solar Rule

What HERS score do I need for Arlington's lot area and frontage exemption?

HERS 44 or lower, or the maximum HERS score in the Massachusetts energy code if that is lower.

Which lots does the Arlington HERS exemption cover?

R0, R1 and R2 lots that already have a principal building, when the new home is built within the existing foundation footprint, with an addition that is not a Large Addition, or by special permit.

Does Arlington require solar on new buildings?

Yes, for projects that need Environmental Design Review, such as six or more dwelling units or mixed-use projects. Solar must cover at least 50% of the roof area unless an exemption applies.