If you’ve been considering a major home remodel or addition in Massachusetts but have been scared off by the insanely difficult energy efficiency requirements of the past few years, we’ve got some game-changing news.
For years, the state's energy code made it nearly impossible to complete larger home renovations without gutting your entire house—even if you only wanted to expand or update part of it. But the latest energy code changes, which took effect in February 2025, have finally made home renovations far more achievable and budget-friendly.
Here’s why this is a huge deal for homeowners and builders alike.
First, what’s a HERS Rating?
Before we get into the details, let’s quickly cover what a HERS rating is and why it matters.
HERS stands for Home Energy Rating System, which is the standard used to measure a home’s energy efficiency. The lower the HERS score, the more efficient the home.
A HERS 100 home is built to the efficiency standards of the 2006 energy code (not very efficient by today’s standards).
A HERS 42 home is extremely energy-efficient—think of a new construction high-performance build with triple-pane windows, thick insulation, and near-perfect air sealing.
A HERS 65-75 home is much easier to achieve and is roughly in line with a well-insulated home built in the 2010s with standard 2x6 walls and double-pane windows.
The problem until now? Massachusetts required many additions and remodels to meet the nearly impossible HERS 42-52 standard, which meant gutting and rebuilding large portions of homes. Now, with the 2025 code update, that requirement has been relaxed to HERS 65-75 for remodels and additions, making projects much more achievable.
The HERS 42 Nightmare: When an Addition Meant a Full Gut Reno
Before this update, if you wanted to:
✔ Add more than 1,000 sq. ft. to your home
✔ Remodel more than 50% of your existing home
✔ Build an addition that was 100% of your home’s current size
You were forced to bring your entire home up to a HERS 42 energy rating—a standard so extreme that, in many cases, it was only possible if you completely gutted and rebuilt the rest of your house.
For context, a brand-new, all-electric, super-insulated house might barely scrape by with a HERS 42 rating if built from scratch. Expecting homeowners with older houses—many with outdated insulation, standard double-pane windows, and existing mechanical systems—to hit that mark? A logistical and financial nightmare.
What Did This Mean for Homeowners?
Massive unexpected costs. Many homeowners had to replace all their windows, add exterior insulation, air seal the entire home, and even upgrade HVAC systems—even if their main project was just an addition or partial remodel.
Permits denied or projects scrapped. Some people gave up on their home renovations altogether because they couldn’t afford the required upgrades.
Builders had to turn down projects. Many contractors struggled to meet these requirements while keeping projects on budget, leading to higher bids and fewer completed projects.
The 2025 Energy Code Fix: HERS 65-75 for Remodels & Additions = Finally Doable
Massachusetts finally listened to builders and homeowners and updated the energy code to something far more reasonable. Under the February 2025 energy code update, major remodels and additions only need to achieve a HERS rating of 65-75, rather than 42-52.
Why This Is a Game-Changer
Most homes can hit a HERS 65-75 with minor upgrades. Standard 2x6 walls with blown-in insulation and basic double-pane windows are usually enough to comply.
No need to gut your whole house. If you’re adding or remodeling, you don’t have to upgrade every single component of the existing home—just ensure the new work meets modern standards.
Much lower project costs. Homeowners can now expand and improve their homes without breaking the bank on unnecessary retrofits.
Key Changes in the 2025 Energy Code Update:
Major Additions & Alterations (1,000+ sq. ft. or 50%+ of home remodeled): Required HERS rating increased from 42-52 to 65-75
Accessory Dwelling Units (ADUs): The rating was kept at 52-58 instead of dropping to the stricter 42-48 range.
What Homeowners Need to Know
New additions still need to meet energy code for insulation, windows, and HVAC. But you won’t be forced into extreme measures just to make the project possible.
If your existing home has decent insulation and windows, you may not need any additional upgrades beyond your remodel or addition itself.
Builders can now price projects more competitively since they don’t have to budget for full-house retrofits.
Final Takeaway: Renovations Are Back on the Table
For the past few years, many Massachusetts homeowners faced outrageous costs or outright abandoned their home expansion dreams due to impossible energy requirements.
But now?
✅ You can expand your home without gutting it.
✅ You can remodel without ridiculous extra costs.
✅ You can work with your existing home instead of being forced to rebuild it entirely.
If you’ve been holding off on your dream renovation or addition because of complicated energy code hurdles, now is the time to revisit your plans.
This is a win for homeowners, a win for builders, and a win for practical energy efficiency in Massachusetts! 🎉
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