Q + A with Development Officer Greg Payne of Avesta Housing’s Oak Street Lofts

The first affordable multifamily building in Maine to achieve LEED Platinum certification, Avesta’s Oak Street Lofts were designed and built by CWS Architects and Wright-Ryan Construction, with sustainability consulting by Thornton Tomasetti. The 37 artist-friendly apartments benefit from a solar preheat system for up to 85 percent of the building’s hot water, high-efficiency condensing boilers, energy recovery ventilators that return 76 percent of the energy in the exhaust airstream, a tight thermal envelope, panelized wood-wall framing to minimize waste, and locally-sourced wood.

Photo courtesy Avesta Housing.

Q: What are the energy costs compared to similar Avesta buildings?
A: The apartments are twice as efficient as a standard apartment. In the first year of occupancy, heat and electricity costs per apartment were just $46 a month, compared with $92 a month for a typical apartment. That’s a $20,424 annual savings for the entire building.

Photo courtesy Avesta Housing.

 Q: What did you learn during the LEED certification process?
A: We learned that location matters. LEED gives a lot of points for housing density and proximity to transportation and services. City transit lines make over 250 stops a day within a half mile of the building, and there are numerous restaurants, shops, and public services within walking or biking distance.

Photo courtesy Avesta Housing.

 Q: What features attracted the most notice?
A: We’ve received national attention for demonstrating that energy-efficient design not only lowers operating costs and creates a more durable building but also doesn’t have to significantly increase construction costs.

Q: What’s next?
A: We’d like to explore rooftop gardening or urban green space.

Learn more at Avesta Housing, Thornton Tomasetti, Wright-Ryan, and CWS Architects.

Q+A with Justin McIver of Main Eco Homes

We asked designer and general contractor Justin McIver what he’s learned from building and living in his first net-zero model home in Sweden, Maine.

Photo courtesy Main Eco Homes.

 Q: How do you build a home that uses less energy than it produces?

• Build only what you need.
• Create a tight, well-insulated building envelope with controlled ventilation.
• Site for passive solar, and put living areas in southern exposure and bedrooms in northern.
• Reduce electric loads with an efficient electric heating system, LED lights, and Energy Star appliances.
• Include alternative energy sources such as photovoltaic solar.
• Live a low-impact lifestyle.

Photo courtesy Main Eco Homes.

Q: Which energy-efficient products performed best?
A: We were amazed by the Mitsubishi Mr. Slim mini-split heat pump’s ability to heat a 2,000-square-foot home located on a windy mountain, while using a third of the electricity of a normal baseboard. We were also able to save $10,000 on less expensive R5 triple-glazed windows by adding insulated honeycomb blinds to get to R10.

Photo courtesy Main Eco Homes.

 Q: Anything you’d do differently next time?
A: Instead of the backup baseboard heater I’d like to try connecting an inline electric heater and thermostat to the heat recovery ventilator (HRV). We’ve also found a double wall with recycled cellulose insulation to be a better, cleaner, and less expensive alternative to foam board and spray-foam layers. Lastly, the three floors provide more space than two people need, so the resources for the third floor could be used for a garage instead.

Photo courtesy Main Eco Homes.

Q: What’s next?
A: We’ll find out this year if the 6.8-kilowatt solar array is enough to get us to net zero. Our total energy bill in January was $149 and by May had gone down to $9. We expect to come out even with solar credit over the summer, but if needed, we’ll simply add more panels.

Learn more at Main Eco Homes.

Q + A with Peter Maher about his Yarmouth solar and geothermal home

Peter Maher, an engineer and principal at Sevee and Maher Engineers, was renovating a home with Slocum Custom Builders in 2009 when he decided to attend a geothermal conference. With the help of friends, he then laid the pipes for his own geothermal heating and cooling system. The heat pumps pull warmth from the earth’s crust in winter and return the heat in summer, and the 8.8-kilowatt solar array installed by ReVision Energy grabs energy from the sun—and the Mahers enjoy the benefits.

Photo courtesy Slocum Custom Builders.

Q: Was the geothermal difficult or expensive to install?
A: It took about a week to lay the 6,400 feet of pipe at a depth of eight feet. Gagnon Heating and Air Conditioning connected the pipes to two ground-source heat pumps and the radiant floor heating. The system cost about $3,000 to $4,000 more than a conventional furnace, but with no annual fuel bills, so it paid for itself in less than two years.

Photo courtesy Slocum Custom Builders.

Q: Have the systems performed well?
A: Yes. Total energy costs for the 4,500-square-foot house are only about $1,500 a year. That’s propane for on-demand hot water and the gas range in the kitchen, as well as electricity not covered by the PV [photovoltaics].

Before renovations. Photo courtesy Slocum Custom Builders.

Q: Anything you’d do differently?
A: The cost of solar has dropped 22 percent a year since 2008, which makes me think we should have waited, but I guess enough people had to pay the higher prices for them to come down.

Photo courtesy Slocum Custom Builders.

Q: What’s next?
A: We have room on the roof, so we’ll see what prices do in the next few years and add enough solar panels to get the house to net zero.

Learn more at Slocum Custom Builders, ReVision Energy, and Gagnon Heating and Air Conditioning.

Q+A with Karen Boffa and Dan O’Shea of Falmouth Elementary

Falmouth's new elementary is setting the standard for school energy efficiency. Designed by Oak Point Associates and built by Shaw Brothers Construction in 2011, it features passive solar siting, abundant natural light and lighting that adjusts for need, solar thermal hot water, 10,000-plus feet of green roofs with gardens, porous pavement to manage runoff, rainwater capture for toilets, and a wood-chip heating system that also serves the middle and high schools. We asked the principal and director of finance which features they like best.

Falmouth Elementary School

Q: What stands out about the school's efficient features?
A: We especially like the radiant floor heating and efficient lighting; the wood-fired boiler is consistently warm and efficient; and conservation is huge from the solar thermal panels that heat the water. There’s also the rainwater collection for toilets.

Q: Was there anything important learned during construction?
A: Despite the sun shelves on the exterior of the building, we found the winter sun was still reflecting on the whiteboards on one of the walls, so we installed shades on the upper windows of the southern side, and that fixed the issue.

Q: What are the heating costs per year?
A: This 145,000-square-foot building costs approximately $50,000 to heat, and that may go down next year by about $10,000, when all three schools are on the same heating loop and wood-chip heating is extended to reduce oil, a total savings of about $150,000 annually.

Q: What happens at the school over summer?
A: The school is used for extended school services and professional development for teachers and is accessed by Falmouth Community Programs for summer activities. The gardens are especially lovely then, too.

Learn more at falmouthschools.org.