BROOKS, Maine — Mitch and Nan Simpson kind of figured their house was not as airtight as it could be, but an energy audit confirmed it in spades.
“It’s definitely an eye-opener, for sure,” Mitch said after Tuesday evening’s audit was completed. “I knew I had problems, but not that many, I guess.”
The audit was conducted by Keith McPherson of Albion, who has been trained and certified by the Maine State Housing Authority. McPherson conducts audits for MSHA as well as through his private business.
He has been busy this winter as the state tries to improve energy efficiency in its housing stock.
“We were aware of what Keith was doing. This is an old house and we think it’s energy efficient and wanted to see if it really is,” Nan Simpson said. “I doubt it, though. I work at home and sit here every day and I know it’s cold.”
An energy audit consists of comparing the amount of heating fuel and electricity used against a home’s square footage. The Simpsons use about 850 gallons of heating oil each year and 1,000 kilowatt-hours of electricity each month.
Without having to be told, McPherson estimated that the family of four would use that much electricity on appliances, drying clothes, water pump and dishwasher. Of the oil, he estimated that about 150 gallons a year were being used for hot water. It was the remaining 700 gallons that McPherson was looking for ways to conserve.
Stepping into the basement, McPherson immediately noticed colonies of cobwebs, a sure-fire indicator of air leaks.
“Cobwebs are a tell-tale of a lot of air movement,” McPherson said. “Spiders want air to bring bugs to their webs.”
The Simpsons’ house was built in the early 1970s, and other than replacing the roof with a metal roof a year ago and replacing the thermopane windows, which had begun to leak, the home has the same amount of attic insulation it did when it was built. It is a split level ranch with an attached garage.
McPherson uses a Minnesota-made blower door specifically designed for measuring a home’s air flow. It is placed over an existing exterior door and has a device to monitor air loss. The blower door acts as a reverse vacuum, sucking in air from the outside through cracks and poorly insulated areas. It measures the number of cubic feet of air flow per minute drawn into the house. A “really energy-efficient” home will have a reading of 300 cfms, McPherson said. The Simpsons’ home was in the 2,300 range.
“When you think about your house, pretend it’s upside down and filled with water,” McPherson told Mitch as he installed the door. “Anywhere the water runs out is where you are losing air.”
After turning on the Blower Door, McPherson surveyed the house from basement to attic using an infrared camera to locate areas where cold air was being sucked in from the outside. He said that 67 percent of heat loss in a house is due to airflow. Plugging gaps will eliminate much of the losses.
The camera found leaks in the basement where the rim joists rest on the concrete foundation and around the cellar windows. Air also streamed in from the door connecting the home to the garage. However, the major loss was in the living areas through the tile ceilings. The camera detected cold air coming through the seams in the 12-inch-square tiles despite the presence of insulation overhead.
Despite the gaps, McPherson said there was “a significant opportunity here” for the Simpsons to improve the situation. He said sealing around the foundation, caulking around widows, and weather-stripping the doors would be fairly inexpensive. The major cost the family has to consider would be to replace the tile ceilings with Sheetrock and install more insulation. He estimated that the family could save 300 gallons of oil annually if they addressed all of the problems.
“The beauty about this house is most of the solutions have to do with airflow problems in the cellar and attic,” McPherson said. “I’ve seen enough to know you’ve got work to do, but there is a significant opportunity here.”
McPherson may be reached at firstname.lastname@example.org, by phone at 437-2787, or through the Maine State Housing Authority Web site.