Planning for a HERS Rating in Massachusetts: What Homeowners Need to Know

Sep 25

If you’re building or renovating in Massachusetts, a HERS rating isn’t just another box to check — it’s your path to code compliance, efficiency, and long-term savings. The more prepared you are, the smoother (and often less expensive) the process will be.

Here are the key things homeowners should have in place before starting down the HERS pathway.

1. Budget for the Essentials

Your contractor should provide clear allowances or pricing for the categories that most affect your HERS score:

Windows
Insulation package
Heating and cooling equipment
Mechanical ventilation
Hot water system
Appliances

Having these details ready gives your rater the information needed to model your project accurately and avoids redesigns later.

2. Make Smart Equipment Choices

The specs you select can make or break your HERS score. Aim for these performance benchmarks:

Windows: U-Factor ≤ 0.27, SHGC ≥ 0.40
Heating & Cooling (ASHP): ≥ 10.4 HSPF2, 20 SEER2
Hot Water (HPWH): UEF ≥ 3.8
Appliances: ENERGY STAR® rated; induction cooktops are a great option for efficiency and all-electric design.

3. All-Electric vs. Fossil Fuels

Any use of natural gas, propane, or oil makes passing a HERS rating more difficult. In new construction especially, where the maximum score is capped at 42, fossil fuel equipment can be a major hurdle. All-electric designs are simpler, cleaner, and qualify for more incentives.

4. Heating and Windows Drive the Score

Massachusetts is a heating-dominated climate zone, which means heating equipment has the single largest impact on your HERS rating. High-efficiency heat pumps are the best option for lowering scores and operating costs.

Windows also play an outsized role. Higher SHGC values (≥0.40) capture passive solar gain in winter, reducing heating demand — one of the easiest ways to improve your score without extra labor.

5. Don’t Overlook Ventilation and Air Sealing

Ventilation: Most homes will need balanced mechanical ventilation (ERV or HRV) to meet code. This not only impacts your HERS rating but also ensures comfort and indoor air quality.
Air Sealing: In new construction, Massachusetts requires blower door results of ≤3 ACH50. Renovations have different thresholds, but in every case, tighter air sealing improves efficiency and your HERS score.

6. The Small Details Still Matter

Some requirements are easy to miss but carry weight:

Hot water lines must be insulated to R-3 or higher
All lighting must be 100% LED
Energy labels and stickers on windows, HVAC equipment, and appliances should be left in place until after inspections — they are required for documentation.

7. Know the Timing

A HERS rating isn’t just one visit at the end. It includes:

Design Phase Modeling – based on your chosen specs and plans.
Mid-Point Insulation Inspection - Verifies that installed insulation levels and placement meet modeled specifications before drywall installation.
Final Verification – inspections and performance testing once systems are installed.

Planning early makes both phases smoother and avoids surprises at final inspection.

Putting the Puzzle Together

Think of your HERS rating like a puzzle: every piece — from equipment specs and window selections to air sealing and documentation — needs to be in place for the picture to come together. Doing so allows for a much smoother modeling process and keeps your project on track from start to finish.