Musty smells in your home are associated with mold or mildew growth from moisture in the air. Mold may grow inside return air ducts, and air flowing through the ducts will carry the musty odor to your rooms. Musty smells may cause headaches or aggravate health issues such as asthma or allergies. Cleaning the ducts will eliminate the smell, but it is important to remove the odor permanently by finding the source of the mold or mildew.
Sources of mold or mildew growth in your home include:
- Attics and basements: Moisture in attics and basements from leaking roofs or damp walls will enter loose joints or cracks in ductwork. Over time, this can result in mold growth in return air ducts. In addition, if insulation covering ducts in unconditioned areas absorbs moisture, mold may grow and the musty odors may enter through cracks in ductwork.
- Condensate drain: The condensate drain carries excess water away from the air handler to the outdoors. When the drain becomes blocked, the excess moisture enters the ducts creating mold or mildew and a nasty musty smell.
- Evaporator coils: Excess moisture forms mold on the coils and the air flowing over the coils circulates the mold spores through the ducts.
- Fan speed: The fan speed set incorrectly for your unit, may add moisture to your ducts. If too much moisture settles in your ductwork mold or mildew will form, sending a musty smell into your rooms.
- Filters: Clogged filters will allow moisture to settle in your return air ducts, producing mold and mildew.
If you have a strong musty smell coming from the return air ducts into your rooms, call a reputable HVAC company to inspect your system and clean your ducts. A professional technician has specialized equipment to vacuum and clean your ductwork. Most homeowners do not have the appropriate equipment to locate the problem and prevent it from occurring again.
For more information on duct cleaning or if you have questions about musty odors in your return air ducts, contact the expert staff at Air-Tro, Inc.Heating & Air Conditioning, serving the Pasadena area for over 40 years.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about air ducts and other HVAC topics, visit our website.
Air-Tro Inc. services the greater Los Angeles area as well as the metro areas of Riverside and San Bernardino County.