A couple years ago, when voters decided to renovate and reopen Longfellow Elementary School on Great Cranberry Island, the project’s main goals were to bring the old, drafty building in line with fire, safety and disability codes: adding sprinklers, floor reinforcements, exit signs, etc.
But the renovation also was a good opportunity to make Longfellow School more energy-efficient, according to Mike Sealander of Sealander Architects. The Ellsworth firm, which Sealander runs with his wife, Robyn Sealander, planned and designed the project.
“We quickly realized this was an expensive building to heat, so we did two things,” Sealander said. “We added insulation and tightened up the building’s air barrier. Then we replaced the existing oil-fired furnace with a propane fired boiler and energy recovery unit.”
Most Mainers don’t live in schoolhouses built at the turn of the 20th century, but as they consider ways to make their own abodes less cold, drafty and energy-inefficient, it’s worth considering some of the principles at work in the Longfellow School renovation.
Design work began in 2014. Construction firm Dunbar & Brawn began the work in 2015 and is just now finishing it, Sealander said.
To keep heat in the building, rigid insulation was added underneath the clapboards, while cellulose insulation was added in the attic. New windows were added on the school before the renovation, but their seals with the walls were improved.
To more cheaply and cleanly generate heat, the propane boiler was added.
And because better insulation can decrease a building’s air flow, Sealander also thought to add the energy recovery unit, which is a device that ensures cold air entering a building is warmed.
Rather than focusing on any single improvement, they have taken a comprehensive approach.
“In order to realize energy savings, through better insulation, you have to think about the whole building at the same time,” Sealander said. “You can’t just think about windows, and you can’t just think about the walls. You also have to think about the roof or ceilings, and a lot of houses around here, they are quite leaky at their foundation.”
There are more things that can be done for energy efficiency, according to Sealander, who recently gave a class on the subject through Ellsworth Adult Education.
They include the use of computers to model the energy savings of a planned upgrade and the use of solar panels to use even less energy.
Sealander’s advice for anyone looking to make efficiency upgrades is not to start with a solar installation, but rather to look at improving something like the insulation on a wall.
That wall might become twice as insulating after one upgrade, Sealander said, but beyond that, a second upgrade may only provide diminishing energy savings.
Once all upgrades are made to the point that future ones won’t get you much bang for your buck, Sealander went on, that’s when a homeowner can start to think about installing solar panels.
“Where the industry is now is, you want to find the sweet spot where you’ve done every energy efficiency measure that’s possible that’s less expensive than a solar panel, and then the next dollar that you want to put in goes to solar panels,” he said.
Sealander, whose firm normally does work for organizations and nonprofits, said homeowners don’t necessarily need to consult a designer before making efficiency upgrades.
The state maintains a list of contractors certified to make efficiency upgrades and, through the organization Efficiency Maine, can provide financial incentives to homeowners who do so.
But a homeowner might want to contact a designer when making an upgrade to one part of his or her house — such as installing new windows or floors — and deciding to making an efficiency improvement at the same time, Sealander said.
That’s what Cranberry Isles did.
Correction: An earlier version of this article contained an error. Dunbar & Brawn started construction on the project in 2015.