by Donna Jensen, Extension Energy Answers Volunteer, Master Gardener and Community Tree Steward
On a bright winter afternoon I sat in my kitchen wearing my blue-striped wool hat and reading the mail. My husband Jeff and I are proud tree-huggers, and by keeping our home's thermostat at 64°F, we minimized our consumption of propane to fuel the furnace. On that brisk day I needed the hat to stay warm.
We didn't view a cool home as a tremendous hardship. We live in New Hampshire. It gets cold here, and we were taught by our respective Yankee parents that you put on a sweater when you feel a chill instead of turning up the heat.
On extremely cold nights Jeff would start a fire in the auxiliary wood furnace in our basement, which really banished the chill. Between very cold evenings and the occasional power outage, the wood furnace got considerable use.
That day the mail contained a survey from the Jordan Institute designed to determine a home's energy use. Your home received a score at the end.
I immediately completed the survey, assured that our sweater-wearing and intermittent wood-furnace use would give us an excellent score. Besides, we built our home 10 years ago. Its exterior walls are filled with thick pink insulation. The home is equipped with double-paned argon-filled windows, and the antique wooden front door is covered by a cold-blocking storm door
Imagine my shock when the survey result indicated that our home was energy-inefficient. But when I thought about it, the result made sense. Our house was typically cold in the winter and hot in the summer, particularly in the second-floor bedrooms. Furthermore, during the winter we always had huge icicles hanging off the roof, indicating that heated interior air had reached the attic and warmed the roof's underside.
The following spring, Jeff and I decided to investigate the possible reasons for our poor survey score by hiring an energy auditor. The auditor arrived carrying a large blower-door instrument. With all the windows and secondary doors closed tightly and the fireplace damper shut, he fit the blower and its tight-fitting skirt over our home's front door. When he powered up the blower, it created negative pressure inside the house and simultaneously measured the rate at which air was sucked into the house through all its "cracks."
According to the findings from the blower-door test, our home's air exchange rate (its "draftiness" measure) was 19. An energy-efficient home would have an air exchange rate many times lower. Thus, the survey result was confirmed. Our house was a real fuel-consuming stinker.
I remembered that whenever I sat beside a fire burning in our living room fireplace, I'd feel a merciless draft in the room. A roaring fire in the fireplace actually made our house feel colder.
Our auditor explained that when the fireplace burned fuel, the warm indoor air went straight up the chimney and was replaced with outside air sucked into the house through unsealed nooks and crannies. For this reason, many homeowners fit their furnaces (and other appliances such as clothes driers) with fresh-air intake vents.
Installing air-intake vents to our propane furnace and clothes drier was just one of our auditor's recommendations. He explained that we must also prevent the comfortable, conditioned air inside the house from leaking out.
So we installed weather stripping around every exterior and interior door, including the knee- wall access doors to the eaves and the door used to reach the pull-down staircase to our attic. We also stopped air from leaking into the attic by caulking the large gap around our masonry center chimney and the attic floor.
The auditor also told us we needed to keep the outside air outside. To achieve that, we followed his suggestions to prevent undesirable air leaks.
Working within the knee wall of the second floor, Jeff fitted each floor joist with a block of foam insulation to prevent the soffit-vented air from entering the floor space. After replacing all our recessed light fixtures with new models rated for direct contact with insulation, we removed the carpets, drilled holes in the floor boards, and blew cellulose insulation into the space between the first and second floors, as well as into the attic floor, mounding it high around the edges where the attic floor meets the roof.
It was a lot of work, but we spent less than $1,000 on insulation and fixtures. It's already paying big dividends.
The house is no longer drafty. On the hottest days of summer, it's only a few degrees warmer in my second-floor bedroom than in the first-floor living room. In late February the fuel delivery person came to fill our 500-gallon propane tank, but didn't bother. He claimed we had plenty of fuel in the tank, but said he'd check again in a few weeks. It's now early April and he hasn't come back. Imagine that! We estimate we've cut our propane use in half.
I now wear my blue striped wool hat only when I go outside.
Photo credit: Blower-door test, by Andy Duncan. Used with permission.