How to Improve Your HERS Score Massachusetts | Builder Tips

Published: May 2026 | HERS ScoreEnergy EfficiencyMassachusetts Builders

Under the MA Stretch Code, new residential construction must achieve a HERS score of 55 or below. If your energy model is coming in too high, here are the most effective strategies to improve your HERS score.

What Is a Good HERS Score in Massachusetts?

Under the MA Stretch Code, the maximum allowable HERS score is 55. A typical new home built to minimum code scores around 100. An Energy Star certified home typically scores 55–75. Net-zero homes score 0 or below.

Highest-Impact Improvements

1. Air Sealing (Biggest Bang for Buck)

Improving air tightness from 5.0 ACH50 to 2.0 ACH50 can drop your HERS score by 5–10 points. Focus on attic bypasses, top plates, band joists, electrical penetrations, and plumbing penetrations. Air sealing is typically the most cost-effective way to improve both HERS score and blower door results simultaneously.

2. Insulation Upgrades

Adding insulation above code minimums — especially in the attic and walls — can significantly reduce the HERS score. Continuous exterior insulation (ci) is highly effective for wall assemblies. Spray foam in the attic and rim joist provides both insulation and air sealing value.

3. High-Efficiency HVAC Equipment

Upgrading from a standard 80% furnace and 13 SEER AC to a 96%+ furnace and 16+ SEER AC (or heat pump) can drop the HERS score by 5–15 points depending on the home’s mechanical load. Cold-climate heat pumps have become increasingly popular in Massachusetts due to their very high HERS improvement and Mass Save incentives.

4. Windows and Doors

Specifying triple-pane or high-performance double-pane windows (U-factor 0.25 or below) improves the HERS score, especially in homes with significant glazing area.

5. Mechanical Ventilation

Switching from exhaust-only to balanced ventilation (ERV or HRV) improves indoor air quality and can modestly improve the HERS score by reducing the energy penalty of ventilation.