Should I clean my air ducts?
by Building Inspector and Indoor Air Specialist, Dan Schilling
© Copyright 2002 Residential Inspections LLC, All Rights Reserved
Here is the plain truth about air duct cleaning.
People often ask me if their air ducts need to be cleaned. There are three differing perspectives; the air duct cleaning company's, the government's, and the right one.
Air duct cleaning companies have an obvious bias to sell their services. Some will pitch the cleaning of the ducts as “the best thing since sliced bread” when it comes to solving symptoms such as allergies or asthma. Yet, most people who have their ducts cleaned realize limited benefit from it. This is because there are many other factors that affect indoor air quality besides contamination inside of air ducts. While air duct cleaning can be very beneficial, it is only one important step toward improving your indoor air quality and reducing the health problems caused by indoor air.
The government states that you shouldn't pay to have your ducts cleaned unless you have evidence of insect, rodent, or mold contamination, or enough debris in your ducts to restrict the flow of air. The problem with the government's recommendations is that you could easily have insect or rodent urine and fecal matter in your ducts without any readily visible evidence. You could also have mold growing in your ducts without it being readily visible. Furthermore, the amount of debris in air ducts does not have to be that significant in order for it to affect your indoor air quality. Even marginally dirty air ducts can host millions of dust mites. Dust mite excrement is one of the most toxic allergens to humans. Each dust mite can excrete up to 20 fecal pellets everyday. Dust mites have legs like spiders allowing them to hang on to the dust and debris in your ducts when the air passes by. Conversely, their excretions can easily become airborne and pass from the ducts into your breathable air. For this reason alone, maintaining your ducts is important.
Many people make the mistake of thinking that the dust in their home is coming from their air ducts. Metal ducts do not create dust, they collect it. In fact, the space inside of air ducts is approximately equivalent to an entire room of a house that never gets cleaned. Air ducts can host a biological eco-system and they should certainly be considered when indoor air quality is valued.
When having your ducts cleaned, do not allow your air duct cleaning company to spray fragrances into your ducts. For some people, chemical fragrances can actually be more offensive than the unclean ducts. Further, you should avoid all chemical cleaners if possible. If the ducts have had mold, insect or rodent contamination, chemical biocides can be used, but make sure they are registered with the EPA for safe use inside of air handling systems. Temporary high levels of ozone can also be used to sanitize and deodorize air ducts without the use of chemicals. Ozone treatments are great for reaching areas that cannot be easily accessed, such as air conditioner A-coils.
with those you care about.