PORTLAND, Maine — Horsepower, sure. But catpower?
Paul Ledman only partially drifted into jest when he talked about the type of activity that can keep his super-insulated, energy efficient multi-unit building heated.
“If the crock pot is on, or the toaster is running, or if three cats are chasing each other, it helps warm the place up,” he said. “Just living here is enough to keep the place warm.”
The 62 Cumberland Ave. structure, on what was previously an undeveloped Munjoy Hill lot, has garnered a lot of attention in local and industry media as what Ledman calls “a model for what can be done” in a world where oil costs are climbing and household incomes aren’t.
The three-unit building uses no fossil fuels, creates enough energy that it exceeds in-house needs and contributes to the grid most months, and yet is hardly Spartan in its amenities — even with a private elevator hopping from floor to floor — Ledman still has electrical capacity to install an outdoor hot tub, which is in his plans.
Outside his bedroom window is a rack of 90 solar pipes, collecting sunlight to warm three hot water tanks. Another array of 30 photovoltaic solar panels provides electricity to the units, and eschewing oil or natural gas, Ledman had air source heat pumps installed to regulate temperatures in the apartments — one of which he set aside for his own family of four.
“People think that in order to be efficient, you have to give something up,” Ledman, who worked with Georgetown-based Island Carpentry to develop the project, said. “Quite the contrary. We’ll take showers and do the dishes and run the laundry — everybody [in the building’s other units] will, too, if they want to — and we won’t pay a penny for it.”
Air source heat pumps extract warmth as necessary from even very cold outside air and directs it inside. Once the warmth is inside, the thick external walls filled with a combination of blown-in insulation and rigid foam board — adding up to an R value of about 43 — keep it there.
In a state with aging housing stock, Ledman said a home built in 1950 might have walls with an R value of 13, for comparison.
“Even on the coldest days, we barely need any heat to heat it,” Ledman said. “The real key if you’re building new is insulation. If you don’t waste [heat], you don’t need to buy more. Anybody who doesn’t build with energy efficiency in mind today is setting themselves up for failure. [Fossil fuel] prices are going to continue rising. [Energy efficiency] is good for your pocketbook, and it’s good for the environment.”
Ledman and wife Colleen Myers promote their home and advocate for green building techniques through Eco Capital LLC, which uses the social networking website Facebook to update followers on energy consumption.
On Sunday, the homeowners reported that they’ve generated 3,600 kilowatt-hours over 1,500 hours — “more energy than we’ve needed for heat, hot water or appliances during that time.” Whatever extra power is generated is banked by Central Maine Power Co., and the couple can tap into that reserve if they come across a month in which the solar collection is low due to short days or heavy clouds. Each month, they pay CMP just $8.53 in standard administrative fees.
The four-story structure includes three garage bays at street level and uses a heat recovery ventilator system to exchange stale, inside air for fresh, outside air without losing the indoor temperature.
The kicker, Ledman said, is that his three-unit super energy efficient building was similar in cost to build as a traditionally heated and powered structure. He described construction costs as around $140 per square foot.
“It’s the only building like this in Maine,” he said. “It’s a multiple-unit building in a city setting that’s completely energy efficient. We’ve got a building that’s about the same cost as a conventional building, but I’ve got almost no utility bills.”