Saving on home energy expenses is a widespread goal, but what’s the secret when costs skyrocket and warmer weather is months away?
Do the next best thing—use a home energy audit to tame those out-of-control high energy bills.
Even small leaks can reduce your home’s energy efficiency. The U.S. Department of Energy says the potential energy savings from reducing drafts in the home range from 5 to 30 percent. In addition to the savings, your home will feel more comfortable after you’ve stopped the heat loss.
A home energy audit will help you determine exactly how much energy your home consumes, uncover the areas where heat is escaping and show you ways to conserve hot water and electricity.
When you think about air leaks in your home, picture a window that’s been left open all winter. The heat loss and wasted energy would be tremendous. That’s why doing what you can right now—before an entire winter of heat escaping your home passes—is critical to putting an end to the runaway utility bills.
To uncover problems and determine a home’s air tightness, a professional home energy auditor comes to your home and will use the blower door test and an infrared thermograph or infrared camera.
The blower door test looks for air leakage and moisture condensation problems and tests the indoor air quality. A blower door is a powerful fan that’s mounted into an exterior doorframe. When turned on, it pulls air out of the house, lowering the air pressure. Then, the higher outside air pressure flows in through all unsealed cracks, holes and openings. This test determines the air filtration rate of a building.
Always make sure the auditor you hire uses a calibrated blower door. This type of door has gauges used to measure the amount of air pulled out by the fan, determines the tightness of the house and can quantify the amount of air leakage along with the effectiveness of the air leak fixes. Uncalibrated blower doors won’t tell you this information.
Another tool used to find leaks, and one of the most important pieces of equipment a home energy auditor uses, is the infrared camera, sometimes called a FLIR (Forward Looking InfraRed) camera. This high-definition resolution imaging camera shows where the hot and cold spots are in the building envelope, information that’s valuable in identify insulation opportunities. This camera forms an image using infrared radiation that operates in wavelengths as long as 14,000 nanometers, which is why it’s not visible to the human eye.
Paul Eldrenkamp, president of Byggmeister in Newton, Mass., asks his home energy audit clients to complete a pre-audit worksheet that includes utility bill information, type and number of appliances, number of occupants and their typical thermostat setting at home.
“With a home energy audit, I can identify for the client where the priorities are,” he says. “Where to put your first weatherization dollars, what subsequent investments should be and what some no-cost steps are.”
Eldrenkamp uses the blower door test, an infrared camera to identify insulation opportunities, a spreadsheet for utility bill analysis and occasionally a Ductblaster to test ducts for leakage in homes with forced air heating systems.
Eldrenkamp says the FLIR camera is “like an MRI for the house. I can see behind-the-wall conditions that I’d otherwise miss completely.”
If you discover energy leaks at home, here are some no-cost fixes Eldrenkamp recommends.
Unplug that nearly empty refrigerator in the basement.
Set the thermostat back before going on vacation.
Replace your old boiler or furnace with a high-efficiency unit before it breaks down completely on New Year’s Eve and you’re stuck replacing it with whatever the heating guy has on his truck, which you’ll then be stuck with for 30 years.
If you’re having an addition or major renovation done, have a blower door test after the insulation work but before the drywall work so that you can fix big air leaks while it’s still easy and cheap to do.
Make sure all the windows are closed when heating or cooling. Eldrenkamp says he did an audit on a house recently where he found a third-floor window that had been wide-open since last summer.
Eldrenkamp typically takes one and a half to two hours on site to conduct an energy audit, a half-hour for utility bill comparison and one to one and a half hours to write his report. When the audit is completed, the client is handed a list of needed fixes, the solutions and the approximate associated costs for those fixes.
Renovate with Tommy Mac used the FLIR infrared camera technology to evaluate the thermal efficiency of a 1,500-square-foot house. Built in the Boston area in 1929, the house has a clapboard exterior, balloon framing with blown-in cellulose attic insulation, a full basement and cinderblock foundation.
When it comes to home energy leaks, the biggest culprit is the attic. This is especially true if you happen to have a floor-to-knee wall juncture in a finished attics. Other sources of common leaks include the chimney and plumbing as well as joists in the basement. Look in these areas for some ideas on where your own energy leak problems might be hiding.
We used the FLIR infrared camera to capture images of four areas that demonstrated energy leaks. Using these photos as examples, Eldrenkamp helps us highlight four affordable, quick fixes as well as four more costly, longer projects to fix the same problem.
Install foam gaskets behind outlet cover and switch plate. Foam gaskets can be used to seal switches and outlets that aren’t paint-sealed to the wall. Air can leak through interior walls, flowing up into the attic and through the exterior wall. Here’s the smart thing to do: Install the gaskets on all your wall outlets. You can also buy plastic safety plugs to stop the air leaks in unused electrical outlets, too, just to be on the safe side. This is something homeowners can do that may improve general comfort for the occupants.
Have the blower door test done to find the major air leaks in the house and deal with those issues in a systematic and informed manner. The infrared camera by itself is helpful but not nearly as helpful as the infrared camera and blower door test together. Cost: $400 to $500.
For houses with attics, use expanding foam or caulk to seal the opening around plumbing vent pipes and electrical wires. Be sure to wear gloves and not get foam on clothing, as it’s very sticky and difficult to remove from clothing once its set. In the photo, there appears to be infiltration at the eave, which can be sealed with the expanding foam from a can. The odd square section that’s reading cold may be a missing fiberglass batt, which should be re-installed. The long line to the right of that apparent void may be a pipe of duct chase that should be sealed where it exits the eave. The recessed light is reading cold, too, which means that it’s leaking air to unconditioned spaces. A box made of rigid foam insulation could be fabricated and fit around the recessed light, making sure there’s at least 3 inches of clearance between the foam box and the light fixture.
Measure your current energy consumption by using your energy bills to calculate your total energy consumption for the past year, expressed in BTU (1 therm of gas=100,000 BTU; one kWh of electricity=3414 BTU; one gallon of heating oil=139,000BTU; one gallon of propane=92,000 BTU). Divide that total by the square footage of your home. If the number is bigger than 50,000 (in a Boston-type climate), you have lots of opportunities to make improvements. Use the blower door and infrared information to put together a plan for reduction, then execute the plan and continue to keep score by tracking your total BTU consumption. Cost: your time and attention to detail.
Caulk around air leak. The triangular gable vent just visible at the top of the photo is reading warm, so it’s leaking lots of warm air from the attic. That warm air is coming up through leaks in the second floor ceiling. Those leaks can be sealed with caulk, spray foam, gaskets or a combination of the same.
Have a HERS rating done on your house. The HERS Index, according to Energy Star’s web site, is a “scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home’s HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.”
Each 1-point decrease in the HERS Index corresponds to a 1 percent reduction in energy consumption compared to the HERS Reference Home. Thus, a home with a HERS Index of 85 is 15 percent more energy-efficient than the HERS Reference Home and a home with a HERS Index of 80 is 20 percent more energy-efficient.
To find out how your home scores on the HERS index, use the score, plus the capabilities of the rating software, to do some “what-if” scenarios for energy reduction to put together a master plan. Cost:$400 to $800
A common area of air leakage in the basement is along the top of the basement wall where cement or block comes in contact with the wood frame. Since the top of the wall is above ground, outside air can be drawn in through cracks and gaps where the house framing sits on top of the foundation. Use caulking to seal cracks or gaps that are less than one-quarter inch long. Use spray foam to fill gaps that are longer and up to 3 inches. You might think about sealing holes for wires, water supply pipes, water drain pipes and plumbing vent stack. Every place where a wire or pipe passes through an exterior wall creates a potential spot for air leakage.
Remember that a 5 to 10 percent reduction in energy consumption will not get you close to the goal of 80 percent reduction by 2050. Cost: diligence in discovering and fixing energy leaks.
After you’ve completed the quick fix improvements, check to see if the fixes are reflected on your home energy statement the following month. Did your energy usage go down? If so, your quick fixes worked. If not, move on to the Not-So-Quick Fixes.
No matter where you live or when your house was built, you can lower your energy usage by identifying the air leaks and stopping them in their tracks.
Credit: Renovate with Tommy Mac