Inspections of your heating and cooling systemâ¤™s ductwork should be conducted on a regular basis. Simply using your HVAC system can cause damage to the ducts, as it has to cope with the internal stresses that are associated with changes in temperature and atmospheric pressure. Also, vermin may sometimes tunnel into the ductwork in order to gain access to the favorable environment inside it.Obvious signs of ductwork aging include the corrosion of the duct materials, mastic tape, or caulk. Leaks and collapsed duct sections should, of course, also be of highest concern. Leaks often cause streaks of dust to emanate from the ducting joints as air escapes under pressure from the system.If any of these signs are observed, this is as good a reason as any to call in professional Rancho Cucamonga air conditioning repair technicians, like Day Aire HVAC, to test the system. After a thorough assessment, they should be able to pinpoint the source of the problem and take steps to remedy it.