The ICAN Climate Solutions library series continued Tuesday with a talk led by South Mountain engineer Marc Rosenbaum: “Beyond fossil-fuel homes.”
Rosenhaum, armed with more than 30 years of experience, is committed to making homes more energy-efficient, comfortable, durable, and healthy. He offered tips to a packed room at the West Tisbury library on how to lessen a home’s contribution to climate change.
First, Rosenbaum encouraged the community to fix what we have, rather than building from scratch: “Most of the buildings we’re going to be using by 2050 are already here. We might as well fix the ones we have.”
Fossil-fuel emissions in a home generally stem from burning oil or gas for heat, and using electricity generated from coal, propane, and oil. Home heaters, AC units, water heaters, kitchen appliances, and dryers are all high-carbon-footprint culprits. Decarbonization strategies include better insulation, and more energy-efficient heating, cooling, ventilation, and refrigeration systems.
Upgrading mechanical system
Many homes have dated mechanical systems with uninsulated pipes and ducts, with boilers situated outside or in the attic. “Part of those systems actually put heat outside,” Rosenbaum said. Better-insulated ducts located inside a heated part of the building are one way to save energy. Rosenbaum also suggested installing better controls for heating systems, and the promise of electric heat pumps and cold-climate heat pumps. He compared cold-climate heat pumps to a fancy refrigerator: “But instead of moving energy from hot to cold, you’re moving energy from cold to hot.”
Heat pumps are reversible, and are able to heat a house in the winter and cool it in the summer. “In the winter, they take heat out from the outdoor air and put it into the house. In the summer, heat pumps take heat out of the house and dump it outside,” Rosenbaum said.
The “off switch” is another potent strategy, one that not only saves energy, but money. At the Plainfield School in New Hampshire, where Rosenbaum spearheaded a project that saved a school energy and money, he touched on how turning off the boiler in the summer saves money and energy — as does turning off commercial appliances like dishwashers and refrigerators when they’re not in use.
“You just have to pay attention,” Rosenbaum said. “You don’t have to have advanced degrees to find the off switch.”
Generating secondary sources of renewable energy onsite through solar panels is another recommended strategy. Rosenbaum commented on the power of a greener grid: “If Vineyard Wind gets past the Trump administration, that project will have enough juice for a sixth of the whole state,” Rosenbaum said. “The grid gets greener every year as coal plants go offline and clean air comes online.”
Improving thermal insulation
Many Island homes are leaky, and upgrading a building’s enclosure is one way to save energy. Weatherization and deep energy retrofit are two key strategies.
Basement crawl spaces, attics, and knee walls are areas where many homes lose energy. Rosenbaum said it’s important to insulate these spaces, and explained a process of depressurizing them using a blower (a big calibrated fan) that shows how many cubic feet of air is distributed per minute, and then using an infrared scanner to see where air comes in.
“There could be plenty of insulation, but that doesn’t mean [the room] isn’t getting energy from the house,” Rosenbaum said. “Air leaking from the house to the attic is called thermal bypass, so we’re trying to seal that.” Foam insulation and gunfoam can seal the leaky spaces.
Deep energy retrofits are also an option for bringing homes up to more efficient energy standards. Rosenbaum said this process costs a lot of money, but can be a good fit for some homes, especially ones that are relatively simple in design and are already suffering significant structural deficiencies.
The Plainfield School in New Hampshire is an example of a successful deep energy retrofit, done in a series of stages over the course of 10 years.
“Beyond Fossil Fuel Homes” was the fourth in a series of six monthly talks hosted at Island libraries, presented by the Island Climate Action Network. The full talk is available on MVTV.