Homeowners who have energy audits performed know exactly where to start improving the energy efficiency of their homes. This service, performed by a licensed auditor or HVAC professional, provides a starting point for home improvements that will help trim energy costs.
The U.S. Department of Energy (DOE) estimates that half the energy consumed in homes are the result of cooling and heating it, followed by heating water. An audit involves a thorough physical inspection of your home and testing with equipment that finds where you have thermal losses through air infiltration and inadequate insulation throughout your home.
Air Leaks
The blower door test is the typical centerpiece of energy audits. The blower door holds a large fan inside an adjustable frame that fits inside an exterior door frame. It has gauges that measure the air pressure indoors. Once all the windows are closed and interior doors open, the auditor turns the fan on and measures how fast the air pressure falls.
The fan pulls the air outdoors and as it does, the air pressure drops. In homes with little air infiltration, the pressure drops quickly. In leaky homes, the pressure won’t fall as fast or as far. While the fan runs, the team uses infrared or thermographic devices that sense heat differences.
Depending on the time of year, the incoming air will have a different color, as long as temperatures are measurably different indoors and out. Otherwise, the team may use harmless smoke pencils that show where the air is drifting indoors and note where the leaks are. Thermographic images are stored as still photos or videos.
Most often the audit will turn up leaks in these places:
- Around exterior door and window frames
- Along the top plate of your home
- Places where any pipes, wires or cables enter the home
- In the attic around vent stacks, flues and chimneys
- Fireplaces dampers
- The outside perimeter of the dryer vent and exhaust fans
Most of these leaks will be easy to seal using caulk, expanding foam and insulation.
Thermal Losses
Besides the air leaks, thermal losses occur wherever insulation is inadequate in the walls and attic and through windows and doors. Single-pane windows have almost no ability to resist heat transfer summer and winter. Heat always seeks to flow to colder temperatures and the process never stops. Insulation slows the transfer in the home’s structure. Inert gases inside dual or triple pane windows stop it and mass inside exterior doors blocks some of the transfer.
Thermographic testing during energy audits will reveal the places where thermal losses occur by showing the differences in color. It can be done both indoors and out to point out where you may need to add insulation to the attic or walls. Installing Energy Star or thermal windows will also help you cut ongoing energy bills.
Adding more insulation to your attic is fairly easy and inexpensive, but if the energy audits turn up poor insulation in the walls, you may want to hire a contractor to blow more inside them. They drill holes in the interior or exterior walls and blow loose insulation inside. The holes are patched and the surface repainted.
Mechanical Systems
An examination of your HVAC system may turn up areas where it’s causing high energy bills. If it’s dirty or out of adjustment, it’ll use much more energy. An HVAC contractor can also test the ductwork using the blower door or other equipment.
Duct leaks can add substantially to your energy bills, since they distribute conditioned air to places where it’s not needed, usually in the attic. The leaks also degrade indoor air quality by pulling dust into your home. If you use vented gas appliances, the leaks can also backdraft carbon monoxide throughout your home.
The auditor may find that your water heater loses heat through standby losses that you can mitigate by wrapping it with an insulating blanket, easily found at home improvement centers. He or she can also show you how to drain a few quarts of water from the heater to improve its efficiency and extend its life.
The pros at Senica Air Conditioning, Inc. can help you learn more about the benefits of energy audits to cut down on energy consumption. We’ve provided HVAC services for homeowners in the St. Petersburg area since 1992.
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