State environmental leaders assembled on Wales Street last week to celebrate the third day of Climate Week and highlight a supportive housing build-out that received $200,000 in state funding for the installation of a high-efficiency heating and cooling system.

Using the state’s Department of Environmental Protection’s (DEP) Gap III grant funding program, the development spearheaded by Heading Home, Inc. – which helps formerly homeless families with children get back on their feet via supportive housing – was able to install an all-electric central heating and air conditioning system throughout the 20-unit building. That environmental high-five contributed to an effort to make the building 100 percent free of fossil fuel use when it is completed next year.

“This is the largest development of its kind in Boston,” said Heading Home CEO Danielle Ferrier. “Those families will also benefit from safe and healthy housing. This is a wonderful way to attack issues both of affordable housing and climate resiliency.”

A big part of that comes via the $200,000 grant to make sure high-efficiency HVAC systems are in place, rather than ones that run on natural gas or fuel oil. State Environmental Secretary Rebecca Tepper is enthusiastic about the ongoing work on Wales Street, which sits off Harvard Street east of Blue Hill Ave. “This is exactly the kind of thing I was hoping I would get to do as secretary – seeing properties like these come to fruition,” she said. “These projects are often piecemeal and we’re happy to be a piece of this project…This is the future and we’re excited to support it. We take this one place at a time, and this is one of those places.”

DEP Commissioner Bonnie Heiple said the investment made in clean energy at places like 37 Wales St. produce a return of nine times the original investment. She said the grant fund helps projects like Wales Street move forward as they don’t always check all the boxes on a traditional development application.

During a tour of the four-story building, which was built on the site of a smaller building that Heading Home owned and operated, consulting project manager Tim Flynn – of Flynn Design + Build - pointed out the all-electric kitchen, the large picture windows usually reserved for market-rate units, and the separation of bedrooms from living spaces.

“The goal is to have a moderately sustainable building to keep costs down for Heading Home,” he said. “They are a homelessness prevention provider and need the savings…As I see it, we’re at the forefront of what Boston is trying to do and that’s exciting.”

Heading Homes’s Ferrier said the new building will offer the same use and has the same purpose as the previous, smaller building that was razed, but will be double the size and more environmentally friendly with better indoor air quality. The family-unit building will be reserved for people with children, with a preference for those from Boston who have been waiting in shelters the longest.

“When you look at homelessness in Massachusetts for families, about 90 percent are single mothers with two or three children with average ages between 2 and 9 years old, so this is going to fit right with the population that needs it the most,” she said.

There will be 17 two-bedroom units, and 3 three-bedroom units, and an office on the ground floor for a case manager who will work on site 40 hours a week to help the families with services and supports.