Location: Cambridge, MA
Size: 14 units
Completed: 2022
Architect / Designer: Davis Square Architects
GC: Callahan Construction
CPHC: New Ecology, Inc

Squirrelwood Apartments Reaches Passive House Building Milestone

Callahan Construction Managers, a full-service construction management company, announced an exciting milestone has recently been achieved with the construction and testing for Passive House Certification at their Squirrelwood Apartments project, an affordable housing development located in Cambridge, Massachusetts.

“We are very proud of our team and partners Davis Square Architects, New Ecology, Inc., Just-A-Start, and Tierney Development Services, LLC for accomplishing these impressive results at Squirrelwood,” said Patrick Callahan, President of Callahan Construction Managers. “The construction process is rigorous, but the team’s attention to detail and commitment to sustainable building and the resident environment have contributed to our success in achieving this together.”

The Passive House verification is a lengthy process which consists of numerous inspections and tests to confirm that the construction meets the PHIUS minimal air infiltration standards.  A standard building will have three full air changes per hour, which equates to air infiltration of 3.0 Air Changes per Hour at 50 Pascals of pressure (ACH50).   A building that meets Passive House standards is expected to take 1 hour and 40 minutes to do the same air cycling, meaning it is significantly tighter at an air infiltration rate of 0.6 ACH50. 54 Market Street far exceeds Passive House standards, with one full air change taking four hours, an air infiltration rate of 0.27 ACH 50.

“New Ecology’s mission is to bring the benefits of sustainable development to underserved populations, and even by those high standards, this is an impressive and rare accomplishment,” said Maciej Konieczny CEM, CPHC, LEED AP, Senior Project Manager, New Ecology. “When this project began, there were no affordable multifamily Passive House projects in Massachusetts, but working with Callahan’s experienced team, a dedicated design team, and an owner that plans for a long-term investment was an example of what’s possible when solving challenges collaboratively.”

Squirrelwood is considered the fourth tightest multifamily building in the country and the tightest building on the East Coast (excluding duplexes). This result along with the other Passive House criteria, such as having the building super insulated, creates a more efficient building because it minimizes heat loss.