Solar for Hamptons New Construction: HERS Requirements Explained
Building or substantially renovating on the East End? Your home has an energy score to hit before it gets a certificate of occupancy.
By Steve Maroney, founder of Power House Home Energy · Updated October 2026
The Towns of Southampton and East Hampton require new and substantially rebuilt homes to meet a HERS score (Energy Rating Index, or ERI), verified by a RESNET-certified rater before the certificate of occupancy. In both towns, homes up to 4,500 square feet need an ERI of 50 or less. Larger homes need 35 or less in Southampton and 31 or less in East Hampton. Neither town mandates solar outright, but solar lowers a home's score, and on large homes it's often the most practical way to reach those targets.
What each town requires
| Home size (conditioned space) | Town of Southampton | Town of East Hampton |
|---|---|---|
| Up to 3,000 sq ft | ERI 50 or less | ERI 50 or less, or the prescriptive path |
| 3,001–4,500 sq ft | ERI 50 or less | ERI 50 or less |
| Over 4,500 sq ft | ERI 35 or less | ERI 31 or less |
East Hampton also adopted the NYStretch Energy Code for building permits submitted after January 1, 2023. Incorporated villages, such as Southampton Village, Sag Harbor and East Hampton Village, can have their own rules, so we confirm the requirements for your exact address.
How solar helps a home hit its HERS score
A HERS score compares a home's energy use to a standard reference home: the lower the number, the more efficient the home. Insulation, windows and efficient heat pumps bring the score down, and on-site solar production brings it down further. On a large home, reaching 35 or 31 with envelope and equipment upgrades alone can be expensive or impractical. Adding the right amount of solar closes the gap.
How we work with East End builders
Designed to the HERS target
We size the solar system with your HERS rater's numbers, so the home hits its required score without overbuilding.
On your construction schedule
We plan around your build, from rough-in to roofing to certificate of occupancy, so solar keeps pace instead of holding things up.
Solar, roofing and heat pumps
One team for the systems that drive the HERS score, coordinated directly with your builder, architect or project manager.
Permits and PSEG Long Island
We handle the solar permit, PSEG Long Island interconnection, inspection and Permission to Operate.
Recent East End new-construction and major-renovation projects with solar by Power House.
Steve Maroney, our founder, has been working on the East End for more than a decade, and Power House works with many East End builders and design/build firms on new construction and major renovations. See our Southampton and East Hampton pages.
Code summaries are based on the Town of Southampton's Energy Conservation code and the Town of East Hampton's Chapter 102 as published. Requirements can change and villages differ. Your HERS rater and building department have the final word.
Common questions
Does Southampton require a HERS rating for new homes?
Yes. The Town of Southampton requires new and substantially reconstructed homes to meet an Energy Rating Index (HERS score) of 50 or less up to 4,500 square feet, and 35 or less above 4,500 square feet, verified by a RESNET-certified rater before the certificate of occupancy.
What HERS score does East Hampton require?
The Town of East Hampton requires an ERI of 50 or less for homes up to 4,500 square feet (homes up to 3,000 square feet may use the prescriptive path instead), and 31 or less for homes over 4,500 square feet.
Is solar required for new homes in the Hamptons?
Neither town mandates solar outright. But solar lowers a home's HERS score, and on larger homes it's often the most practical way to meet the required score.
Do you work directly with builders and architects?
Yes. We work with many East End builders and design/build firms, design the solar to the project's HERS target, and schedule around the construction timeline.