A smart solution for two families reducing their carbon footprint.

Two different households (representing three generations of the same family) moved from two larger single-family homes to this structure on a quiet Belmont street within walking distance of MBTA bus lines, shops, and services. The primary reason for the move was a strong desire to make a substantial reduction in their carbon footprint. Their newly acquired two-family home needed everything: new kitchens, bathrooms, siding, windows, roofing, and HVAC — a perfect candidate for a deep energy retrofit.

Two Family Retrofit

  • Belmont two family before
  • Belmont two family after rear view
  • Belmont two family retrofit exterior insulation
  • Belmont two family window and exterior foam
  • Belmont two family siding in process

Byggmeister's Solution

Environmental crusaders, the owners were eager to participate in National Grid's deep energy retrofit pilot program. And, in fact, theirs was the second home to succesfully complete the program.

In addition to implementing the National Grid prescriptive goals of R-20 basement walls, R-40 above-grade walls, R-60 roof, and R-5 windows, the project team was able to achieve an impressive air leakage reduction of nearly 90% (from 5700 cfm@50 to 590 cfm@50) and a HERS reduction from 197 to 32.

This home has met the prestigious Thousand Home Challenge, a program that recognizes verified deep energy reductions in existing homes. It has also been featured as a case study on the website of the Building Science Corporation.

Project Location

Belmont, MA