Two southern Maine builders have teamed up with Kaplan Thompson Architects on a subdivision that will include as many as 26 houses built to net-zero standards.
The first of the houses in a Wells, Maine, subdivision called Brackett Estates, is a 1750-sq. ft., three-bedroom model called the Appledore, which was completed in mid-June. The two-story, all-electric house includes double-stud walls insulated to R-40, triple-glazed windows, and a roof insulated to R-60 with dense-pack cellulose. It’s on the market for $429,000, or just under $250 a sq. ft.
Among its other energy features:
- Mitsubishi ductless mini-splits for heating and cooling.
- A heat pump water heater for domestic hot water.
- Passive whole-house ventilation with wall-mounted air inlets and timed bathroom fans.
- A 4.3 kilowatt, grid-tied photovoltaic array mounted on the roof.
Architecturally, the house has a contemporary New England flavor, with an exterior finished in white (vinyl) clapboards, a porch protecting the front entry, and an attached, two-car garage. Inside, the house is clean and bright with amenities that Futuro hopes will interest savvy buyers: strip maple floors, granite countertops, high-end kitchen appliances and an attached deck at the rear of the house.
But the emphasis is clearly on performance. Ware says the design follows the 60-40-20-10 insulation standard, meaning the roof is insulated to R-60, walls to R-40, basement walls to R-20 and insulation beneath the slab at R-10.
Because insulation was still to be sprayed on the inside of basement walls in early July, blower-door test results were not available. Architect Phil Kaplan said the house was designed with Passive House energy modeling software, and that he hoped it would test at between 1.5 and 2.0 ACH50 (the Passive House standard is 0.6 ACH50).
Modular construction with net-zero capability
The house was built by Keiser Industries in Oxford, Maine, and delivered to the site in 48-ft. long modules. Keiser is the same modular builder that Kaplan Thompson had worked with previously on a pilot project to deliver two net-zero modular homes to Peaks Island in Casco Bay, just off Portland. That project has been on hold.
Ware says that the idea is to deliver a building envelope capable of net-zero energy performance even if homeowners choose not to add renewable energy systems as soon as they move in. Houses will have conduits running from the basement to the attic allowing easy installation of PV panels at a later date.
At the model house, the PV panels added about $12,000 to the price tag after federal rebates. The 4.3-kW capacity, Ware says, is a little short of being able to deliver net-zero performance. To get all the way there, homeowners would have to add slightly more PV capacity.
Futuro took what steps it could to keep the house affordable. The siding, for example, is vinyl, and kitchen cabinetry while better than basic, is, in Ware’s words, “not over the top.” Bathrooms are relatively modest in size with tile floors but plastic, not tile, shower surrounds. Another cost-cutting move, Ware says, was not to seek LEED certification, which would have added some $5,000 to the cost.
In all, there are four house models, ranging in size up to 2400 sq. ft. Futuro hopes to build seven houses this year, but if demand over the next 30 to 60 days is strong, the partnership may extend the road into the subdivision to speed up construction.
Betting on strong demand
Despite efforts to keep costs down, the houses are not inexpensive, and local real estate agents quoted in an article about the project in the Portland Press Herald weren’t convinced the houses would have broad market appeal.
But Ware is betting buyers will be willing to invest in a house where there are no energy costs.
“We’re betting they will,” he says. Using energy modeling, architects determined the house would be 67% more efficient than a house with the same floor plan built to current energy code standards, Ware says.
And even with significantly more insulation and triple-glazed windows, Kaplan says the house is no more expensive to build than one of comparable size without the energy features, mainly because it doesn’t need a conventional heating system.
“I got real serious about this two years ago,” Ware says, “and starting looking around for a place to do it. My initial inspiration was to go to NESEA and see some of the homes that were done down on the Cape in Massachusetts, and we said, ‘Gee, we need to bring those to Maine.’ I think this will work.”
This also seemed like the right time to try a net-zero community in the area. Wells is within easy driving distance of the greater Portland area, as well as both New Hampshire and Massachusetts.
“Real estate sales were starting to uptick in this area,” he says. “That was one thing that made us feel more comfortable about doing this, and I think it was just a gut feeling that the time was right to get this kind of construction out to the mainstream public. And that’s our goal here, to try to bring a green, self-sustainable product to a middle-range buyer, to make this attainable as possible.
“So often you say, ‘green’ or ‘net-zero’ and people go, ‘Oh my God, I’ve got to spend a million bucks.’ It doesn’t have to be, and we’re proving that here. It doesn’t have to be a million dollar house. We’re in the high threes, starting, and that’s a pretty good value, I think.”
Get building science and energy efficiency advice, plus special offers, in your inbox.