The Comfort of Home

Does your air conditioning system smell musty? Take a look at the questions to ask if your AC system spreads an odd odor around your home with every use.

Are the Air Ducts Moldy?

While most homeowners don't need to schedule a special air duct cleaning service regularly, some special circumstances may cause this part of your central AC system to get more than just dusty.

According to the U.S. Environmental Protection Agency (EPA), research doesn't point to duct cleaning as a way to prevent health problems. Even though the ducts may get dusty (especially if you don't regularly change the filter), it's more likely the dirt will stick to the interior surface than spread out throughout your home.

If the AC blows a musty smell throughout your home and you think the ducts are at fault:

• Call a professional. You can only see the first foot or so into the system's air ducts. Even though the immediate surfaces may look clean, mold or mildew may lurk deep in your home's duct system. An HVAC professional can inspect the ducts and find the source of the problem.
• Inspect the insulation. The ducts themselves aren't the only surfaces that can support mold or mildew growth. The musty odor your air conditioner makes may come from moldy insulation. If your ducts are wrapped in insulation, check these areas for moisture, mold, and mildew.
• Remove the moisture. Mold and mildew require moisture to grow. If the ducts are clean and dry, it isn't likely these common culprits are the cause behind the musty odor.

Mold cleanup isn't a do-it-yourself job. This is a repair for an expert. Failure to remove the entire cause (all the mold spores) could result in regrowth

Does Your Home Have Pests?

While mold and mildew are primary causes of musty duct smells, other issues can also result in odd odors. Pest droppings left behind by mice, rats, or other critters can cause a similar musty smell. If your home has a pest problem, eliminate the issue and schedule a duct cleaning to remove any leftover debris.

Is the Condensate Line Blocked?

The AC's condensate line allows excess moisture to leave the system. If the line clogs, it can cause a backup and block the flow of water as it exits the evaporator coil. The blocked condensate line or pump can grow mold, causing a musty smell in your home.

Air conditioning systems shouldn't smell musty. If your AC has an odd odor, contact a qualified HVAC repair contractor for an immediate inspection and repair of your air conditioning system.