Heating, ventilation, and air conditioning systems have been shown to collect a variety of contaminants such as mold, fungi, bacteria and very small particles of dust that have the potential to affect overall health, The removal of such contaminants from the ventilation system and home should be considered one component in an overall plan to improve indoor air quality.

The best way to determine if the ventilation system cleaning was effective is to perform a visual inspection of the system before and after cleaning. If any dust or debris can be seen during the visual inspection, the system should not be considered cleaned. While you can perform your own visual inspection using a flashlight and mirror, a professional cleaning contractor should be able to allow you better access to system components and perhaps the use of specialized inspection tools. 

Frequency of cleaning depends on several factors, not the least of which is the preference of the homeowner. Some of the things that may lead a homeowner to consider more frequent cleaning include:

• smokers in the household
• pets that shed high amounts of hair and dander
• water contamination or damage to the home or HVAC system
• residents with allergies or asthma who might benefit from a reduction in the amount of indoor air pollutants in the home’s HVAC system
• after home renovations or remodeling
• prior to occupancy of a new home.

The most effective way to clean air ducts and ventilation systems is to employ source removal methods of cleaning. This requires a contractor to place the system under negative pressure, through the use of a specialized, powerful vacuum. While the vacuum draws air through the system, devices are inserted into the ducts to dislodge any debris that might be stuck to interior surfaces. The debris can then travel down the ducts to the vacuum, which removes it from the system and the home.