Air Duct Leakage
Ductwork and Duct Leakage Testing and Evaluation
Better Care for Air
Ductwork is cool. Except when it's hot. If you have central air conditioning, forced-air heating or both, your house contains a
ductwork system that distributes conditioned (heated or cooled) air throughout your home. You have supply ducts that "blow"
conditioned air to your various rooms, while return ducts bring air back to the furnace or air-conditioning unit so that this air
can be heated or cooled and then redistributed. This cycle continues until your thermostat tells your furnace or AC unit that the
right temperature has been reached.
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What's at Stake:
Sound Ductwork Makes a Difference
It's important for any home energy checkup to include thorough ductwork testing and
evaluation. Properly sized, properly installed ductwork is critical in any heating and
air-conditioning (HVAC) system. Unfortunately, ductwork is frequently overlooked when
evaluating your home's energy performance, despite its importance. As a result, bad things
Leaky supply ducts let air you've already paid to heat or cool "leak away" before it gets
into your home. Leaky return ducts allow unconditioned air from your attic, basement, or
crawlspace to "leak into" your system. In both cases, the air that reaches your living space
isn't as warm or cool as it's supposed to be, so your comfort is compromised.
If conditioned air leaks away before it reaches your living space, obviously you're not getting something that you paid for. If air from your hot attic or
your freezing basement or crawlspace leaks into your system, it takes more energy (and money) to either cool it down or warm it up to make it
usable for conditioning your living space. In essence, you could be cooling or heating the great outdoors without even realizing it!
Indoor air quality
If you have return duct leaks, you could be pumping "bad air" directly into your living space whenever your system runs. You wouldn't want to
breathe crawl space or attic air all day, but if you have this uncontrolled leakage, you might be! Leaky ducts also cause indoor air quality problems
because of "pressure imbalances" that put some rooms or areas under positive pressure and others under negative pressure. This can cause
unhealthy air (laden with dirt, dust, pollen, allergens, and other contaminants) to be sucked into your home.
Pressure imbalances caused by leaky ducts can cause backdrafting in combustion appliances such as furnaces, wood stoves and gas ranges.
When this happens, you risk exposure to carbon monoxide, a deadly gas.