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Web exclusive: The home energy audit

Find out what to expect and learn more about blower door tests
Contact your local cooperative’s energy advisor or member services manager to see if your co-op offers home energy audits. If so, the advisor can walk through your home, pointing out areas where you may be wasting energy to air leaks, duct leakage, insufficient insulation, or aging “energy-hogging” appliances.

When you schedule a home energy audit, you can expect the advisor to investigate the following basic areas of your home. The entire process usually takes about an hour, perhaps a little longer, if a blower door test is done. Before the audit, be sure to discuss with your advisor your main areas of concern—whether it’s working toward greater energy savings, better indoor air quality, improving the safety or comfort level of your living space, or all of the above.

During an audit, energy advisors will check:

• Building type: manufactured/stick-built/apartment, condo, or duplex/other.

• HVAC equipment: in proper working order with no major issues, ductwork, age, appropriate installation, possibly if scaled properly to home. All energy advisors will advise the member to have the system properly inspected by an HVAC professional.

• Type of heating system(s): geothermal/heat pump/electric furnace/baseboard/gas, wood, propane/other.

• Type of AC system(s): geothermal/heat pump/forced air.

• Duct work: physical condition and inspect for leaks in either intake or outtake vents.

• Basement: type (crawlspace/slab/finished) and quality of insulation.

• Attic: insulation levels and areas of air leaks.

• Roof ventilation: working status of ridge vents and soffit vents, check for obstructions.

• Insulation: levels in ceiling, floors, basement, and around rim or band joists.

• Water heater: age, type (freestanding/point of use/electric/gas or propane), and presence of insulation.

• Thermostat: setting, presence.

• Air quality: quality of HVAC filters in place; whether they need replacement.

• Windows and doors: physical condition and the air seal around them.

• House exhaust fans: presence in bathrooms, for dryer, and stove/grill.

• Building tightness: are large leaks (e.g., around can lighting or doors) visible to the naked eye?

• Air sealing: a blower door test may be done to determine percentage of air leakage per hour.

• Temperature differential: some auditors may use infrared cameras to identify areas where conditioned air is leaking from the home (e.g., near attic entryways, unsealed ducts or vents, or poorly insulated doorways).

• Appliances: working efficiency, age, presence of ENERGY STAR models.

What is a blower door test?

• A blower door test can help identify how airtight your house is. The test is used to determine whether—and where, precisely—you may need to work on improving the air sealing in your home.

• During the test, a professional energy auditor will mount a powerful fan to your home’s front door. The fan pulls air out of the home, lowering the pressure inside. This causes the higher outdoor air pressure to flow in through any available leak in the home. The auditor can then use a smoke pencil to identify these air leaks around your home’s windows, doors, or exterior penetrations and within the ductwork.

• The Department of Energy estimates that homeowners can save 5 percent to 30 percent on their energy bills by implementing upgrades following a home energy audit.

Why airtightness matters

A tighter house means:
• Reduced energy consumption because of air leakage.
• Reduced moisture condensation/humidity problems.
• Greater home comfort by reducing uncomfortable drafts (i.e., cold air leaking in from outdoors in the winter).
• Improved indoor air quality.

How to prepare for a blower door test

• Close windows and open interior doors.

• Shut fireplace dampers, fireplace doors, and wood stove air intakes. Clean the ashes out of fireplaces and wood stoves to prevent them from being sucked out and scattered inside the house during the blower door test.

How the test works

• A blower door makes use of a powerful fan that mounts into the frame of an exterior door to your home. Gauges attached to the fan detect the pressure differences inside and outside the home, while an airflow manometer measures the amount of air (in CFMs, cubic feet per minute) that is leaking from the house.

• The results of the test will tell you what percentage of your conditioned air (i.e., heated in the winter or cooled in the summer) is leaking from your home per hour. Anything greater than 40 percent air leakage is considered too high.

• Building science has improved to the point that new homes often have less than 25 percent air leakage. That’s good news for energy efficiency, but the home still needs a source of fresh air exchange. Many new homes make use of an energy recovery ventilator (ERV), an intentional exchange ventilator that brings in temperature- and humidity-controlled air from the outside. Put simply, ERVs offer a controlled way of ventilating a home, while minimizing energy loss.

Read more energy-saving tips in the Kentucky Living 2015 Energy Guide.

Robin Roenker 

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