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Leaky 1900's Farmhouse turned into a cozy, comfortable, energy efficient home through National Grid's Deep Energy Retrofit Pilot Program. Currently on track to meet the Thousand Home Challenge.

What You Need to Know


Deep Energy Retrofit included the following: • Roof: R-60+ In the new addition – 11.25” rafters with dense-pack cellulose inside and 4” foil-faced polyiso outboard of the sheathing. In the main house – 7” of dense-pack cellulose in the existing rafters and 4” rigid foam board. • Walls: R-40+ in the new portion – 2x6 walls blown with cellulose, and 4” foam board on the exterior. • Existing Brick Foundation: R-20+ 4” spray-applied closed cell foam with protective barrier applied to the exterior of the foundation • Windows: R-5 Triple-glazed casement windows with low-e coating by Accurate Dorwin. • Doors: R-5 Therma-Tru fiberglass exterior doors. • Air Sealing Final Test: .083cfm/SF @ 50 PA • Heating and Water heating: Retain existing Veissmann hot water boiler. • Ventilation: Venmar EKO 1.5 ERV for heat and moisture recovery. Very low energy consumption: >2cfm/Watt • 3.8 kW PV System

Other Benefits:

Air tight house removes the need for air conditioning in the summer by simply using nighttime ventilation.

Efficiency or Sustainability Improvements:

Removed a dormer to optimize space for new 3.6 kW grid-tied PVarray. A new roof replaced a leaky slate + cedar shingle roof.

My Motivation:

For us the priority was to use less fossil fuels and have a smaller carbon footprint long term.


Get a whole house energy plan before embarking on improvements. When we needed to replace the burner 6 years ago, we could have saved considerable money by focusing on the envelope first, which would have allowed for a much smaller HVAC system.

Experience with Installer:

Steve Ferrari is an expert in energy efficient building and was excellent on the details, so important to get right. He's constantly educating himself on new technologies and is in the front of the field when it comes to deep energy retrofits.

Open House Info:

Open House Hours: 9:00 am - 12:00 pm Address: 24 Hampden St (off South Street) in Northampton.

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