Atlantic green: a look inside one of the tightest homes in Massachusetts
The Massachusetts coast seems an unlikely place to build a home that doesn’t include a central heating system. Winters there can be brutal, with fearsome Nor’easters kicking up 60 mile-per-hour winds and sideways snow from the Atlantic Ocean.
But that’s just the kind of home that Max Horn built in Hull, Mass., a small town located on a peninsula 15 miles south of Boston. The 2,800-square-foot passive solar home, built in 2009 high on a bluff overlooking the Atlantic, has five bedrooms, and four baths. It features a solar water-heating system and relies on a single gas stove and a few heat-coil ceiling fans for its heating source.
The home was part of the National Solar Tour last Saturday, Oct. 2. Horn beamed when visitors asked about his monthly utility bills, which average a little less than $100 a month. Last year, he said, he only used those backup heating sources on two or three occasions.
“I’ve visited quite a few homes during solar home tours over the years, and I was quite inspired by what some other people have done,” said Horn, a real estate investor who is a longtime member of the Northeast Sustainable Energy Association. “I wanted to do the right thing when I built this house.”
Horn was able to build his home without central heating or cooling because so much attention was placed on the building envelope during the design and construction phases. He claims that the house is one of tightest homes in Massachusetts. It was built with 12-inch double walls, and utilizes dense pack cellulose for insulation. The walls have an insulation value of R-40, while the attic rates at R-60.
The home was made further tight with the addition of triple-glazed windows, a 14-inch I-joist hot roof and taped exterior sheathing. Horn chose concrete shingle siding, which came with a 25-year guarantee. The majority of the windows are located to the east, with carefully selected openings to the south, and relatively few to the north.
The home was built by Hingham, Mass.-based Bradley Woods. Coldham and Hartman Architects, of Amherst, Mass., was the architect and designer.
“It was pretty exciting for us to work with somebody like Max, who had a passion for getting this done, and getting it done the right way,” said Jesse Selman, project manager for Coldham and Hartman. “The home is designed with a real understanding that heating and cooling homes will be challenging in the future as energy becomes drastically more expensive or less available.”
The peak heat loss for the home is approximately 35,000 btu/hour on the coldest day of the year, not including any internal gains. According to Selman, most boilers or furnaces are rated at 100,000 btu/hour for the smallest unit. So the home’s super efficiency allows it to maintain its warmth without a furnace. In addition, its energy recovery ventilator recovers and re-circulates 80 percent of the home’s energy.
The home’s blower door test is rated at .7 air changes per hour @ 50 pascals (ACH50), far exceeding the Energy Star suggested rating of 5 air changes per hour. Blower door tests measure the cracks in a house and how much heat escapes from a building.
Selman says great measures were taken to reduce this number, including borrowing a fog machine from local nightclub, filling the house with smoke while pressurizing it, and observing outside to view where the smoke was escaping in order to isolate leaks.
“We very much think of the envelope of a building as part of the mechanical system, and if you get the walls and floors and the roof of the building to perform well enough, you need less btu’s to heat the building,” says Selman.
Horn took a number of other sustainable measures when building the home. It contains all Energy Star appliances, and Horn says its Energy Star rating is nine times higher than the Energy Star baseline. Horn used concrete windowsills and countertops, recycled rubber roof shingles and non-toxic products throughout the home. Horn is also on the waiting list to receive one of the first Toyota Prius plug-in models when they come out next year.
But the energy-saving measures remain the shining star for this home.
“To eliminate a heating system in a new home and enjoy the payback of not having heating bills is huge,” said Bradley Woods owner Jerry Taverna. “In my opinion, the steps that Max took to get there aren’t all that expensive. It was mainly a matter of shielding the house, paying attention to the amount of insulation in the walls, and having the ventilation system to assure that you have fresh air coming in all the time. If you can do all those things in a new home design for 10-15 percent additional costs, it’s well worth it.”