When our clients purchased a tired 1920’s house in a desirable, walkable neighborhood, their mission was to renovate and stay a while.  As the structure needed major work, they seized the opportunity to go well beyond the minimum code requirements for energy efficiency and do what is called a Deep Energy Retrofit (DER).  By taking a whole-building approach, much greater energy efficiency could be achieved than with a piecemeal approach to renovations and replacement of components.      

With a typical renovation, insulation is installed between the exterior studs and the roof rafters (shown in pink).  This leaves many paths for heat loss through structural members and small gaps in the framing.  In a Deep Energy Retrofit, an additional continuous, air-tight layer of high-performance insulation is installed over the roof, the exterior walls, and the foundation shown in blue).  It is akin to putting a “Cozy” over a teapot for keeping the tea warm.

In addition to the air-tight, high-performance insulation, the following were specified:

• new electric mini-split, heat pump HVAC units

• a heat recovery ventilator (HRV)

• triple glazed windows

• preparations for future photo-voltaic solar panels on the roof.

AFTER:

It is estimated that the Deep Energy Retrofit process will make the home over three times as energy efficient as when they purchased it.