Leaky Ducts in the Home May Result in Poor Indoor Air Quality
If you have defective ductwork serving the central cooling or heating system in your home, losing air before it arrives at its intended destination can be a serious problem.
However, leaky or otherwise defective ducts may cause a worse problem – degraded indoor air quality. When you combine reduced heating or cooling performance with eroded air quality in your home, you’re facing some serious issues.
How Leaky Ducts Degrade Indoor Air Quality
Following are four ways that defective ductwork can erode air quality in a home.
- Dirty air can seep into ducts that aren’t tightly fitted or have gaps or holes. This can happen with ductwork that runs through areas that aren’t heated or cooled, such as crawl spaces, wall cavities, a garage or unfinished basement, and which contain dirty or contaminated air.
Because of the air pressure differential between the inside and outside of the ducts, outside air may flow into the ductwork and then get distributed in your home. Imagine the degradation to air that’s been contaminated by a dead rat or black mold situated near a leaking section of ductwork.
- Negative air pressure can pull in dirty air. This is related to the prior point. Proper duct design calls for the supply and return sides of an air delivery system to be balanced. If your duct system is losing air via leaky ducts or badly designed routing through wall cavities, negative pressure can result.
The air pressure will equalize by drawing in dirty air from outside, as well as from crawl spaces, the garage, basement, etc.
- Backdrafting may occur. This occurs when a combustion appliance such as a water heater or furnace emits potentially deadly carbon monoxide or other toxic gases, and those gases get sucked into defective ductwork.
This isn’t common but it does happen.
- Leaking ducts can compromise humidity control. Leaky ducts in a forced-air HVAC system can pull in moist air from a damp crawl space or basement. Since your AC dehumidifies the air while cooling it, additional moisture in the air it is treating will increase the equipment’s workload.
This increases energy costs, places additional stress on the system, and may make the conditioned air muggy and clammy.