Deep energy retrofit strategy, illustrated.

Graphic depicts the suite of building energy performance retrofits employed to decrease a Boston apartment building’s energy consumption by 73%.

Home energy retrofits, assessments and building science have been front-and-center in our minds lately at Hammer & Hand as we complete dozens of home performance energy audits and energy remodels.

So, it was in this context of “total home performance immersion” that our building science team leader Skylar Swinford shared this link about an inspiring multifamily deep energy retrofit in Boston, Massachusetts.  It’s an impressive story, accompanied by great “visual communication” that succinctly explains the project’s retrofits measures to a lay audience.

The Castle Square Apartments in Boston is a 1960s affordable housing project that will soon become the nation’s largest deep energy retrofit.

The development is resident-owned and the deep energy retrofit project is spearheaded by the building’s denizens.  They describe the retrofit project as “enclosure driven”, meaning that it will focus primarily on the six sides of the building (four walls, roof, and foundation) to dramatically reduce Castle Square’s heating and cooling demand.  The retrofit will wrap the development’s buildings in a new, airtight, super-insulated shell, a measure that will reduce heating needs by 61% and cooling by 68%.  Residents will live in their units throughout retrofit construction.

The website’s illustrations – well worth a closer look – depict their deep energy retrofit approach, with close parallels to the advanced building science strategies of Passive House.  Here’s the suite of retrofits, arranged in what appears to be order of priority:

1.    super insulate
2.    air seal
3.    scale down heating and cooling equipment
4.    improve indoor air quality
5.    harness the sun
6.    reduce plug load

Result: A whopping 73% reduction in building energy consumption.

This Boston project will quickly become a national model of deep energy retrofits at the multifamily building scale.  We trust that Portland won’t be far behind, with growing interest in Passive House design and construction bubbling up in our city’s affordable housing community.  Here’s to a little friendly bi-coastal rivalry!

– Zack

P.S. Image courtesy of Deep Energy Retrofit – Castle Square.