The first vaopr-out Deep Energy Retrofit in the National Grid DER pilot program using Roxul exterior rockwool for insulation and Tyvek for air sealing

What You Need to Know


As part of the National Grid DER Pilot Program, this residence is being retrofitted with R-60 roof, R-39 walls, R-20 basement, R-5 windows and doors as well as comprehensive air sealing and a HRV for ventilation.

Other Benefits:

HVAC is the #1 residential energy consumer thus minimizing heating load typically has the most "bang for the buck".

Maintenance Requirements:

N/A; insulation and air sealing is a completely passive system requiring no additional maintenance; that is the elegance of this approach.

Efficiency or Sustainability Improvements:

All energy Star appliances as well as CFL or LED lighting throughout.

My Motivation:

We needed a new roof and siding but were holding off until eventual plans for a small addition came to fruition. When we learned about National Grid's DER pilot program it transformed into an exciting endeavor in energy efficiency.


It takes time, attention to details and care but in our case thanks to our builder/architect as well as open-minded contractors it has been thankfully a smooth project so far (knock on wood)!

Experience with Installer:

The one thing I learned in this process is that contractors work on small margin so they typically like to do what they know quickly so they can keep work flowing. Unusual projects intrinsically take more time and a contractor can look at it one of three ways: 1) A potential time rathole that could eat up all margin 2) A challenge 3) An opportunity to learn sustainable building methods on the job (getting paid to learn). Many contractors (reasonably) see these projects as #1 so it can be tricky to find the right people. In our case we were extremely lucky; our GC as well as all his subs saw this project as either #2 or #3.

Additional Notes:

This project has four very tough challenges: 1.The structure had a internal polyethylene vapor barrier and the we did not wish to disturb the interior, which necessitated the envelope be vapor-out. 2.Structures in this urban neighborhood are close together and after witnessing a local fire in the past, the we were interested in the fire ratings of insulation. 3.Basement water problems 4.Funds for the project were limited Our architect, National Grid and Building Sciences Corporation were up for the challenge!

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