Just in time for the start of a brand new year, the nation’s largest deep energy retrofit of an affordable multifamily housing project — or any type of building, as far as I'm aware — was awarded with LEED Platinum certification last month following an extensive, non-gut renovation that's been two years in the making.

Built in the 1960s with little regard for energy efficiency, the Castle Square Apartments was, until recently, a hulking, brick and concrete monstrosity on the edge of Boston’s South End near Interstate 90. Once upon a time, I lived and worked in the neighborhood and frequently passed Castle Square's quartet of mid-rise towers on bustling Tremont St. (and if I recall correctly, there was a decent hardware store located in one of the ground-level commercial spaces). But that was over 10 years ago and, just like the rest of the South End, the massive, 540,000 square foot housing complex for low- and moderate-income folks has been subject to some sweeping changes as of late.

Spearheaded by the complex's owners, Castle Square Tenants Organization and WinnDevelopment, the $50.5 million deep green retrofit project has resulted in a 72 percent reduction in energy use with annual utility bills costs are anticipated to drop by a staggering $227,578 due largely in part to the installation of an innovative, super-insulated exterior shell measuring 5-inches thick. Not only did the shell treat the dated façade of the towers to a much-needed aesthetic makeover, but bumped the insulating value of the walls from a measly R-3 up to R-40. In combination with extensive air sealing work, the shell is expected to reduce the buildings' heating needs by 61 percent and cooling needs by 68 percent.

“We basically wrapped it in a blanket,” WinnDevelopment president Larry Curtis explains to EcoHome. He adds: “We wanted to effectively prove a case that the existing inventory of apartments, especially inventory of affordable housing apartments, are a great candidate for rehabilitation for savings and energy.”

Castle Square Tenants Organization president Ann Moy speaks more on the makeover-y"fitting in" aspect of the shell in a Dec. 10 press release announcing the LEED Platinum achievement: “The Deep Energy Retrofit renovation has transformed Castle Square Apartments from an outdated 1965 red brick structure to a modern contemporary design that blends in with the increasingly affluent neighborhood that surrounds our community."

In addition to the insulating shell, the towers of Castle Square were topped with new, super-insulated reflective roofs (R-40) and solar thermal panels. High-efficiency fiberglass casement windows (R-5), high-performance HVAC equipment, Energy Star appliances, and energy efficient lighting was also installed in the units and in the common areas.

And although a bulk of the retrofit work took place in the four seven-story towers that are home to 192 units, all of the apartments in the 500-unit complex, including the 308 units located in the 19 multifamily townhouses directly behind the towers, were treated to green makeovers including fresh coats of low-VOC paint, improved ventilation systems, recycled content flooring, and various energy-related upgrades resulting in energy savings of 48 percent. This figure is notably lower than the more significant savings achieved in the newly insulated towers — it doesn't quality for "deep" energy retrofit status which, by definition, applies to projects with energy savings of greater than 50 percent — but it's still higher than the standard savings of 20 to 30 percent found in most green buildings.

The complex also received an environmentally sensitive landscaping re-do and the addition of a green community center for residents, that according to the aforementioned press release, will be used to further expand the community’s “academic partnerships and program offerings” including an “Early Education Childcare (EEC) licensed after school and middle school program, Environmental Science technology, and youth leadership and entrepreneurship.” The center will also provide the Castle Square Tenants Organization with the raw space to start and expand additional programs for both teens and seniors.

This is all mighty impressive stuff but perhaps notable is the fact that such an extensive/effective energy retrofit only minimally disrupted the tenants of Castle Square (keep in mind that this wasn’t a gut renovation and that the insulation was added to the exterior of the building). In most cases, residents were put up in furnished apartments for a week while their own units were outfitted with new appliances, windows, etc. The residents themselves were actively involved —or at least invited to be actively involved — throughout the design and renovation processes.

Larry Curtis explains to EcoHome: “Often people will say there’s little disruption, and there ends up being maximum interruption. We created hospitality units on-site within a section of the project so that we could effectively hopscotch people through the building and move them one section at a time.”

In additional to several other honors, WinnDevelopment and the Castle Square Tenants Organization were jointly awarded with a “Green Residential Award” and named a “Climate Action Leader” by Mayor Thomas Menino back in May. I should also point out that the project, financed in part by the Department of Housing and Urban Development (HUD), the Massachusetts Department of Energy Resources (DOER), and the Boston Redevelopment Authority (BRA), created 655 new construction jobs. Local firm Elton + Hampton Architects served as the architect for the project while Biome Studio and Building Science Corporation both served as environmental consultants.

There's a lot, and I mean a lot, more about Castle Square's deep energy retrofit including additional info on the team and the financing along with plenty of before and after photos over at the project’s homepage.

Via [EcoHome], [Deep Energy Retrofit Castle Square]

Matt Hickman ( @mattyhick ) writes about design, architecture and the intersection between the natural world and the built environment.

Boston's Castle Square Apartments receives royally efficient retrofit
After the nation's largest deep energy retrofit, the Castle Square Apartments in Boston's South End achieves LEED Platinum status.