Green by design
Hollis Montessori School joins select group
HOLLIS — Form doesn't often follow function with the warmth and style of the new Hollis Montessori School on South Merrimack Road.
Set in a renovated and expanded apple pie factory and surrounded by 9½ acres of orchard and town conservation land, Hollis Montessori officially opened the new school in April. The building is a certified "passive house," a new generation of green construction that cuts energy use by 70 percent with a combination of technology and design that dovetails with the Montessori approach to education.
Frank Grossman, president of the school's board of directors, said sustainability and a low environmental impact were priorities for the school's founders and friends, so they decided to explore passive house designs and standards.
Passive house design originated in Germany in the early 1990s. It has been used primarily for residential housing. But over the past five years, the concept has been gaining ground throughout the construction industry.
The U.S. Green Building Council's Leadership and Energy and Environmental Design (LEED) standards and certification look at a range of different design and construction practices such as how a building affects the environment, water efficiency, waste reduction and the use of local materials and resources.
Energy usage counts
In comparison, passive house standards and designs have a far more narrow focus.
"Passive house involves a set of building specifications concentrated on how much energy you use," Grossman said.
Passive house designs rely on airtight structures with heavily insulated walls, foundations and roofs. Buildings face south to get the maximum benefit of the sun's light and heat.
A ventilation and energy transfer system keeps fresh, outdoor air flowing in and stale indoor air moving out. But before the old air is expelled, heat or energy is extracted and used to either warm or cool the incoming air.
To put all of that into practice, the Hollis Montessori Board turned to architect David Ely and his New Boston firm, Windy Hill Associates.
"I had been looking into passive house for awhile," said Ely, who specializes in energy-efficient design. "I knew the energy performance standard was very high, but I had questions about whether it was worth it."
But after working on the Hollis Montessori School, Ely has become a passive house fan.
The site lent itself well to a passive house design since the south side of the building looks out onto a rolling landscape of hills, woods and apple trees. Ely's design used large triple-pane windows that fill rooms with natural light.
"In the winter, we get almost all of our heat from the sun," he said, adding that the roof overhang helps reduce the heat during the summer when the sun is higher.
For Ely, one of the biggest challenges was making sure the building remained airtight. Every time a plumbing or electrical subcontractor came in to drill a hole for a pipe or a wire, Ely followed up to make sure it was properly sealed.
Other elements of construction such as the 12-inch double-studded walls with two layers of blown in cellulose insulation and the 24 inches of insulation on the roof work with the special ventilation system, designed by Jordan Goldman of the Boston-based company Zero Energy Design, to dramatically cut energy use.
While it may seem like a lot of extra work and expense, Grossman said it was a relatively small investment with a big pay back.
"It cost about 10 percent more than traditional construction," he said.
The school offers programs for kids ages 3 to 15 and is divided into five multi-age classrooms. The Montessori approach to education is a hands-on system that give kids the freedom to follow their own interests at their own pace. There are no rows of desks, no chalk boards and no bells.
"I didn't have a lot of familiarity with Montessori schools so I did some research beforehand," Ely said.
Ely then designed classrooms with lofts, open communal spaces and smaller niches. Kids can choose to work together or independently without interruption.
For lead teacher Kari Headington, one of the nicest aspects of the new school is the relationship between the building and the environment.
"I like the flow from the indoor to the outdoor with the windows that visually let in the environment," she said.
As for the kids, Headington said they like the fact that classrooms have sinks, counters, bathrooms and furniture that's built to each age group's physical size.
The interior of the school also features plenty of wood, linoleum and wool rather than nylon carpets.
"We tried to use as many natural and clean materials as possible," said Grossman, who added the school also tried to stick with local businesses.
And all of that's made easy work for Brent Carney, who does public relations work for the school.
"Other schools are coming to check this building out," he said. "We are becoming a model."
Hollis Montessori School has already carved out a unique niche when it became the only Montessori school in New Hampshire to offer a program for middle school students.
Now, it's one of only three passive house schools in the country and the only passive house school in the Northeast.
With 80 kids now enrolled and room for at least 70 more, Grossman and the other founders and board members hope the school will grow and generate a longer list of accomplishments.
"All of the school's founding families and friends have gotten involved because they wanted to have a school that would be sustainable and would last," he said.