• After a two-year deep-energy renovation, the 500-unit Castle Square Apartments in Boston's South End received LEED-Platinum certification.

    Credit: Lynne Damianos

    After a two-year deep-energy renovation, the 500-unit Castle Square Apartments in Boston's South End received LEED-Platinum certification.

When WinnDevelopment and Castle Square Tenants Organization partnered to renovate a 540,000-square-foot property in Boston, they forged the nation’s largest deep-energy retrofit of an affordable housing community, while managing little interruption to the residents.

“Often people will say there’s little disruption, and there ends up being maximum interruption,” says Larry Curtis, president of Boston-based WinnDevelopment. "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.” 

Residents at Castle Square Apartments were temporarily displaced in furnished units for about a week while their units were renovated with myriad new high-efficient cooling/heating equipment and appliances.

But the driving element was the non-standard method of intensive air sealing, which helped the 500-unit building receive LEED-Platinum certification after the building reached a 72 percent reduction in energy use.

“We basically wrapped it in a blanket,” Curtis says. A 5-inch super-insulated skin coated the outside of the building, giving an added facelift to the property, which had been in poor condition and lacked proper insulation. The exterior took months to complete, and the total renovation spanned two years.

Although it can be incrementally more costly up-front to work around residents, Curtis says, in the end they were left with a fully occupied building that maintained its affordability. What’s left is the educational aspect: The developers are ensuring residents know how to use the new services and equipment to reap the most benefits from the building, which will see a $227,578 reduction in utility bills annually.

The property serves as a large-scale illustration of not only the importance of preserving affordable housing, but the possibility of doing so in a way that far improves upon the original design.

"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,” Curtis says.

The $50.5 million renovation was financed through a series of funding sources, including MassHousing, the Department of Housing and Urban Development, Massachusetts Department of Energy Resources, Boston Redevelopment Authority, Bank of America, NSTAR, and National Grid, as well as grants from The Kresge Foundation and Enterprise.