A family builds a net-zero-energy home in Hyannisport.
While looking for ways to reduce the carbon footprint of Billerica-based biotech firm Millipore, then-CEO Martin Madaus made a discovery: Electricity was frequently the largest waste of resources in the company’s buildings. His solution? “We changed air systems that were outdated and inefficient, retrofitted lighting systems, and installed solar-energy array generators,” he says. His efforts reduced Millipore’s greenhouse gas emissions by 15 percent in three years.
So when Madaus, who now works for Cambridge startup Quanterix, had the opportunity to build a vacation home in Hyannisport for his family, he decided to apply what he’d learned on the job. Madaus contacted A + E Architects, a Brewster firm that specializes in sustainable design, to create his 2,200-square-foot home. It would be principal Alison Alessi’s first time creating a net-zero-energy building — one that produces as much energy as it uses — and she was eager to take on the challenge. “[Designing this way] requires a lot of homeowner involvement, since it results in a new way of living for them,” she says.
Dollars and Sense
The construction budget was roughly $600,000, only about 15 percent more than the average cost of a similarly sized home in the area. In other words, Alessi says, “It’s not cost prohibitive to do this,” but you have to be willing to go the extra mile. Most of the extra money went to super-insulating the house, which required deeper framing and high-tech windows. As a result, Madaus spent less on mechanical systems, since the weather-tight project didn’t need a furnace or a boiler.
SunPower photovoltaic panels were installed on the house’s metal roof, and there’s room to add more in the future. These panels harness sunlight to produce about 8,600 kilowatts of energy per year, more than enough to heat, cool, and light the home. “Massachusetts is really supportive of using solar energy,” says Madaus, who took advantage of the generous state and federal rebates to defray costs. Because excess electricity produced by the panels goes back into the energy grid, Madaus receives an energy credit that can be applied to future bills or another residence — like his year-round home in Lexington.
Extra insulation is a key factor in the home’s efficiency. Eleven-inch-thick walls feature a layer of blown-in cellulose, and there are four inches of rigid insulation under the roof. Consequently, the home’s R-value, a rating that reflects its resistance to heat flow, is 40 — double that of the average house. Alessi also installed Loewen triple-glazed windows, which prevent heat loss in the winter and help keep rooms cool in the warmer months.
All heating and cooling systems are electric, a concept that Alessi says tends to scare people: “Clients think [the house] must be a nightmare to heat, but that’s not the case if [it’s] well insulated.” She installed a mini split-heat pump, a small, ductless heating system by Mitsubishi with an outdoor compressor and an indoor air-handling unit. Because the house is zoned, you only need to heat or cool the spaces you’re in. With such a tightly sealed building, though, ventilation is critical. To keep indoor air fresh, the home utilizes a heat-recovery ventilator by Lifebreath, which preheats cold, fresh air using the house’s warm exhaust.
Although the home, which was completed in the summer of 2011, could easily have earned LEED platinum status, Alessi and Madaus agreed to bypass the certification and direct the hefty registration fee toward making the space as efficient as possible. One of the best things about the house, says Madaus — who regularly kite surfs and kayaks with his sons at the beach down the road — is that he expects it will pay for itself in five years. How many homes can you say that about?
A SieMatic kitchen and limestone countertops were among the Madaus family’s few splurges.
To maximize ocean views, the upper floor has an open plan that includes the living, kitchen, and dining areas.
The four bedrooms are located on the lower level.