Deep Energy Retrofit

Definitions vary, but a Deep Energy Retrofit (DER) is frequently considered to be a carefully designed set of improvements to an existing home that can achieve a 50%, 75% or greater reduction in annual energy use.

There is currently a great deal of interest in DERs by some utility companies, notably National Grid and NSTAR, which have launched their Deep Energy Retrofit Pilot Programs  in Massachusetts. 

An overview of this project, a three story, two family home in Belmont, MA.  is available here.

An overview of a single story ranch in a western suburb of Boston, is available here.

An overview of a three story three family in Boston is available here.

An overview of a three story 'Philly style' two family in Medford, MA is available here.

An overview of a three story two family home in Somerville, MA is available here.

An overview of the first National Grid DER certified as Zero Net Energy is available here.


A portfolio of our Deep Energy Retrofit work, complete with 'all the numbers' is available here.

Excellent DER resources, program description at 1000 Home Challenge