A pair of statewide incentive programs in Massachusetts is driving a surge of apartment buildings designed to the highly energy-efficient passive house standard.
In the past year, families have moved into 257 affordable housing units in complexes built to the standard, and about 6,000 additional units are now in various stages of development.
Early numbers indicate that this building approach costs, on average, less than 3% more than conventional construction and can slash energy use roughly in half. Air quality is higher in these buildings and residents report the units being more comfortable to live in. Many developers who have tried passive house building have been so pleased with the benefits for residents that they are eager to pursue more projects built to the standard.
“We’re getting closer and closer to the mainstream,” said Aaron Gunderson, executive director of Passive House Massachusetts. “The incentives help people get over that initial hesitancy to change and, once they discover what passive house is, there’s no looking back.”
Passive house is a performance standard that calls for a drastic reduction of energy consumption as compared to a similar, conventionally designed structure. Buildings that meet the standard have airtight envelopes, insulating windows, and continually insulated exterior walls.
In Massachusetts, single-family homes built to the passive house standard have been popping up since the early 2000s, Gunderson said. The approach is particularly suited for use in multifamily buildings: Because they contain many units within one super-tight building envelope, the ratio of exterior surface to living space can be very cost-effective, architects said. Until recently, however, developers were skittish about trying a new, higher-cost approach on these larger projects.
Targeting multifamily homes
In 2018, the Massachusetts Clean Energy Center stepped in with a grant program aimed at easing these financial concerns. The Passive House Design Challenge awarded eight affordable housing developments $4,000 per unit — for a total of $1.73 million — for new construction built to the passive house standard. The selected projects range from 30 units in the oceanfront city of Gloucester to 135 units in the Boston neighborhood of Mattapan.
Then, in July 2019, Mass Save, the organization that administers the utilities’ legally mandated energy efficiency programs, launched its own passive house incentives. Available to both affordable and market-rate developments, the incentives offer payments for each stage of building: Up to $5,000 is available for feasibility studies and up to $20,000 for pre-construction energy modeling. Additional money is paid out upon certification.
These incentives have been vital in sparking the growth of high-performance multifamily building, said Dave Traggorth, principal at real estate advisory firm Traggorth Companies, which is currently developing two passive house projects with a total of 57 units.
“Anything that takes some of the bite off of that cost is helpful, especially in an environment where the costs are going upward every day,” he said. “It’s definitely an important part of the equation.”
Within the Mass Save program, buildings that attempt to build to the standard but fall short of certification are also eligible for a performance incentive.
“This is good, because most people are scared of this idea of pass-fail,” said Beverly Craig, senior program manager at the clean energy center. “They’re giving you a bonus for trying.”
And the trying is yielding both information and inspiration, said architects and developers involved in these projects.
Five of the eight projects that received the clean energy center grants are now occupied, and the reports on the projects are very encouraging, Craig said. The results so far suggest that cost increases are mainly driven by the need for better ventilation systems, the price of high-performance doors and windows, and the expense of having the building’s performance professionally verified, she said. The costs for heating and cooling equipment, on the other hand, are generally lower in passive house construction, she noted, because less power is needed to control the climate inside the airtight envelope.
Professionals who have worked on these highly efficient multifamily projects are often eager to do so again.
Boston-based contracting company Haycon, for example, delved into high-performance construction techniques with an apartment development it built in 2020. Though that building was not passive house-certified, Haycon’s experience on the project convinced the company to pursue future passive house developments. The firm is currently building three multifamily projects according to the passive house process — one in Boston, one in the adjacent city of Chelsea, and one in the suburb of Hamilton.
“We learn something with every project,” said Haycon project manager Patrick Larcom. “Ultimately it will become easier and more mainstream and more achievable.”
Affordable and efficient
The affordable housing sector has taken a particular interest in passive house building. The increased attention to airflow and air quality, along with better temperature control, make these homes healthier places to live, an advantage for populations that generally face more medical issues (and costs). Further, the sharply reduced cost of operating a certified building allows organizations to pass savings on to tenants through lower rents.
The North Shore Community Development Coalition received a clean energy center grant to support the construction of Harbor Village in Gloucester, a 30-unit affordable housing development. Heat is included in the rent, but tenants are responsible for their own electric bills, which will include the cost of running air conditioning. Passive house construction will allow the community development group to keep rents more reasonable and save tenants money on their portion of the utilities.
“Too often with low-income families they really struggle to pay high energy bills,” said Mickey Northcutt, chief executive of the organization. “We really try to moderate that cost.”
The organization has been so satisfied with the passive house experience in Gloucester that it is building 46 more units to the same standard in the nearby city of Salem.
There are less tangible benefits as well, Northcutt said. In the past, affordable housing has often been designed and constructed more poorly than market-rate housing. The housing built as part of the Passive House Design Challenge, however, is all high-quality, modern, and attractive. Homes like these can help lessen the negative perception of families that are struggling financially, Northcutt noted.
“Still in 2022 there is a lot of stigma around affordable housing,” he said. “We feel that if people can live in an attractively designed building that is also the greenest building in Gloucester, there’s a bit of pride in that.”
Correction: This article was updated to correct the full name of the North Shore Community Development Coalition.