Chances exist that lint that has in fact been restricting the exhaust vent over a prolonged time period can cause overheating which in turn can cause a fire. The establish of lint that occurs over a prolonged amount of time is not merely a fire threat, it is also a clothing dryer problem that gradually steals the energy efficiency of the clothes dryer and gradually cost you significantly more money.
How often you should clean your air ducts depends on your situation. If you or someone in the home has asthma or is acutely allergic to certain airborne materials or pollen, regular duct cleaning may be helpful. The Environmental Protection Agency doesn’t have an official position on the necessity of air duct cleaning unless the ducts have been contaminated by rodents, insects or mold, or you are aware of particles blowing out through the vents. The EPA recommends you have your air ducts cleaned on an as-needed basis. The National Air Duct Cleaners Association (NADCA) suggests having air ducts cleaned every three to five years.
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