When you have a performance test done, a certified energy rater
comes to your home to evaluate everything from your insulation and
heating system to the operation of your appliances and the interior
design of your home. The rater performs several tests, including a
blower door test, which tests how well sealed your home is from air
leaks. The airtightness of a building is useful knowledge when trying
to increase energy conservation or decrease indoor air pollution.
The results of these and other tests are fed into state-of-the-art
computer software and sent over the internet, which processes the
data. What returns is a quantitative analysis of your home's energy
efficiency detailing R-values, recommended improvements and a
monetary cost/benefit analysis.
After testing is completed, you will be given a written diagnosis of
your home with all of our findings, and a detailed prescription for
fixing any problems that may have been detected.
Duct Testing: Why It Is Important!
The ducts that are part of the central heating and cooling systems offer one of the best opportunities to increase
your energy efficiency, increase your comfort, and manage your utility bills. Studies indicate that 10% to 30% of the
heated or cooled air is lost through leaky ducts. Causing many things to happen the most important being the cost to
Energy cost or losses are not the only concern! Duct systems can also affect the comfort of the occupants (family,
employees, tenants, or customers), as well as the indoor air quality. Testing the ducts will locate leaks helping focus
the repair in the most needed areas. A properly operating heating, ventilation, and air conditioning (HVAC) system
will help reduce overall energy use especially during the hot summer days when air conditioners are working harder
and putting a strain on the electrical system.
How They Work
A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house,
lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and
openings. The auditors may use a smoke pencil to detect air leaks. These tests determine the air infiltration rate of
Blower doors consist of a frame and flexible panel that you can place in a doorway, a variable-speed fan, a pressure
gauge to measure the pressure differences inside and outside the home, and an airflow manometer and hoses for
There are two types of blower doors: calibrated and uncalibrated. It is important that auditors use a calibrated door.
This type of blower door has several gauges that measure the amount of air pulled out of the house by the fan.
Uncalibrated blower doors can only locate leaks in homes. They provide no method for determining the overall
tightness of a building. The calibrated blower door's data allows the auditor to quantify the amount of air leakage
and the effectiveness of any air-sealing job.
Here are just a few of the problems resulting from duct leakage:
- Leaks in the supply ductwork cause expensive conditioned air to be dumped into the attic, crawlspace or garage
instead of into the house.
- Return leaks pull outside air (hot in summer, cold in winter) into the duct system reducing both efficiency and
capacity. In humid climates, moist air being drawn into return leaks can overwhelm the dehumidification capacity of
air conditioning systems causing homes to feel clammy even when the air conditioner is running.
- Heat pumps are particularly susceptible to comfort complaints from duct leakage, especially during the heating
season. Duct leaks can cause the air coming from heat pumps to feel luke-warm or even cold during the winter. In
addition, leaky ductwork has been found to greatly increase the use of electric strip heaters in heat pumps during
the heating season.
- Leaks in return ductwork draw air into the house from crawlspaces, garages and attics bringing with it dust, mold
spores, insulation fibers and other contaminants.
- Household depressurization from duct leaks and imbalanced duct systems can cause spillage of combustion
products (from furnaces, water heaters and fireplaces) into the house.