The results of the so-called Massachusetts Super Insulation Project are in, and the numbers are good.
The Cheimets and Page families live in an Arlington, Mass., duplex that used to consume as much as 1,082 gallons of heating oil a year. But after the building underwent an energy efficiency retrofit in late 2008 and early 2009, and after a year of monitoring, the duplex's total usage has fallen to just more than 350 gallons.
“This is a 66% to 68% reduction in oil usage,” even with the "inefficient legacy steam heating systems" in place, marvels Alex Cheimets, who lives in one of the units with his wife, Nye Kuo, and their two kids.
Blower door tests conducted before the house received an energy efficiency update revealed what everyone already knew: The suburban Boston duplex was highly inefficient. The pre-retrofit results came in at 7,268 CFM/50 for the entire house with 15.6 air changes per hour. Those numbers may not mean much to most people, but suffice it to say that the figures are terrible. Once the work was done, those numbers were lowered to 2,275 CFM/50 with 4.9 air changes per hour.
When BUILDER caught up with Cheimets in March 2009, he and his family had been living with the retrofitted project for several months. Now after living in the home for an entire winter, the owners have not only reduced their carbon footprint and saved money on energy; they are much more comfortable in their homes too.
“It’s warmer on the upper floor in the winter because the heat is no longer escaping,” Cheimets says. “Now we run the heat once or twice a day.”
The results of this Massachusetts pilot project comes at a time when green building consultants and building scientists are debating the benefits of energy retrofits and whether or not it is the best way to improve the energy performance of an old home.
Cheimets feels that it is, but also acknowledges that the retrofit was a big project.
“How difficult could it be to retrofit an 80 year old two-family for state-of-the-art energy efficiency? Really,” Cheimets wrote jokingly on the project’s blog. “Stuff a little insulation here, a little caulk there, replace a few light bulbs, and yell at the kids to take shorter showers ... and you are done."
“These are all great ideas, and by all means caulk away, but they won't get an 80-year-old house (or any house already built) ready for 2050 when our carbon budget will be 80% less than it is today,” he wrote. “You need to do more, more than can be accomplished with caulk, more than can accomplished by insulating the 3-1/2" deep cavities of your 80-year-old walls, more than can be accomplished by screaming at your kids through the bathroom door. Trust us.”
In this case, Cheimets did more, a lot more. Work on the 3,200-square-foot building cost about $90,000—a new roof and new siding artificially inflated the final cost—and focused on tightening the building envelope. The team installed new doors, more than 50 double-pane Pella fiberglass windows, Tyvek stucco wrap, two layers of 2-inch Dow closed-cell foam board, furring strips, and NuCedar cellular PVC siding.
They also installed two layers of 3-inch foam board on the roof deck, followed by plywood sheathing, and light-colored asphalt shingles. Icynene open-cell foam insulation was added to the attic roof and in the basement rim joists and ceiling. Finally, the team installed a heat recovery ventilator and an on-demand water heater for one of the units.
Cheimets admits that the numbers from the blower door tests could be a lot lower, and work will be done to improve the results. “I feel that number would be significantly lower once we do a quality control check on the insulated ceiling,” he wrote in an email. "... If we do a Hollywood fog pressurization and see where the fog leaks out, we will be able to kill every ceiling leak.”
Now that the project is done, Cheimets said he would do it again--but also would probably renovate in phases to spread the costs out over a longer period of time. He will be collecting more data to share with officials at Massachusetts Department of Energy Resources and the local electric and gas utility, NSTAR, which is monitoring real-time oil usage as well as temperature and humidity levels inside and outside the house.
Nigel Maynard is senior editor, products, at BUILDER magazine.
Learn more about markets featured in this article: Boston, MA.