Energy Audits: Lowering utility bills by increasing energy efficiency
Thursday, December 13, 2012
The thermostat – a small but mighty device.
For some, it’s a godsend. For others, it’s the bane of their existence – especially when it reads 70 degrees, and yet it feels as if someone switched out the house for an igloo overnight.
In a typical home with a forced-air heating and cooling system, about 20 percent of the air moving through the system is lost due to leaks and poorly sealed connections, according to the Environmental Protection Agency. The result – higher utility bills and uncomfortable temperatures.
Energy auditor Dan McNeil visits leaky houses on a daily basis, and he has good news. Not only are many energy efficiency problems an easy fix, but they’re relatively cheap, too.
McNeil has been auditing over the last three years for Grow South Dakota, a private non-profit corporation in Sisseton dedicated to promoting economic development in communities. Recently the agency was contracted by Montana-Dakota Utilities as a part of their new MDU Energy Audit Rebate Program, which began in August of this year.
South Dakota is the first state in which the program is being offered, according to Mark Hanson, senior public relations representative of the MDU Resources Group.
“It’s a great tool to help customers determine where they may be losing energy in their home,” Hanson said. “In some cases it could be a relatively easy fix that could save them quite a bit of money over the long run.”
The first program audit, which was done by McNeil, took place early this month at Julie Bolding’s Pierre residence, which was built in 1935. Bolding, a management analyst for the South Dakota Department of Transportation, lives in a historic neighborhood and was interested in improving her insulation while still retaining the home’s historic character.
Bolding said she first found out about the program from an insert that came in her MDU bill. She was happy to take advantage of the $50 subsidized audit, and is looking forward to McNeil’s evaluation of the cost effectiveness of possible improvements.
During an energy audit, McNeil evaluates the house as a whole. He inspects its borders, the insulation in the walls, the window to wall ratio, appliances, crawl spaces and the attic and basement. All of his calculations then go into a computer program, which shows the paybacks – how much you would invest versus how much you would save. This model, known as Savings to Investment Ratio or SIR, presents an accurate reflection of a specific house and customer, McNeil said.
While Bolding’s is the first MDU audit McNeil has done, his prior experience points to attic insulation as a typical contributor to air leakage. The standard used to be six to eight inches of insulation, but McNeil said with South Dakota’s climate, current recommendations are 16 inches, if there’s room. Other common culprits include basements, chimneys and windows.
In order to evaluate how severely certain areas are leaking, McNeil uses techniques such as thermal imaging, which compares temperatures or moisture in the house, and a blower door, which depressurizes the house to simulate a 25 mph wind on all four sides.
After the blower door frame is placed inside the door frame, McNeil takes pressure readings throughout the house to determine where insulation or sealing is most needed.
“Back in the 70s, there wasn’t such a thing. You would caulk around the windows and gaps in your house, but you never really had a way of quantifying your data,” McNeil said. “We can go into a house that’s leaking at a 5,500 cubic feet per minute rate, and we’ll drop them to under 2,000. That’s one of the biggest reasons why I would push people towards audits, because there’s so much more we can tell nowadays.”
Another factor McNeil takes into account when determining the proper ventilation of a house is the number of people living there. Since people give off carbon dioxide and moisture, a lack in air flow can create a moldy environment and prevent gas-burning appliances from operating correctly.
“We want to tighten the house up and save people money, but we don’t want to take it to a point where moisture builds up or indoor air quality is suffering because of it,” McNeil said. “What good is it to throw $5,000 to sealing your house up, if moisture is going to ruin everything that you did?”
Once McNeil has finished an audit, he’ll come up with a work plan and decide which tasks have to be contracted, such as hiring local electricians to work on ventilation by installing fans. McNeil then returns to inspect the work after it’s finished.
Often times he’ll offer simple remedies to efficiency problems, such as sealing unused doors, weather stripping windows, insulating walls or dampening a chimney. In Bolding’s case, these simple fixes might do the trick.
“With a house like this, which to me is one of the most common houses you’ll find, we’ve already come up with a lot of things that will stop the cold air from coming in that probably won’t cost but a couple hundred dollars,” McNeil said. “This is what we find day in and day out.”
While McNeil doesn’t usually get to see the economic impact on his clients’ future utility bills, there is one almost immediate gratification – hearing a customer say that it feels warmer already.
For more information on MDU’s energy audit rebate program, visit their website www.montana-dakota.com/southDakota/Pages/Overview.aspx.
For general information about conserving energy, check out the EPA’s guidelines for reducing energy use www.epa.gov/greenhomes/ReduceEnergy.htm and the Iowa Energy Center’s guide to reducing heating and cooling expenses www.iowaenergycenter.org/wp-content/uploads/2012/03/HomeSeries2.pdf.