Most residential duct cleaning should be performed about every five years or after a renovation. Ducts do get dirty, but the majority of the time it the furnace motor, blower wheel, heat exchanger and evaporator coil that become dirty and clog up the system. These can cause breakdowns and increase energy usage.
A little thought will give you the answer as to why. Why are you ducts getting dirty in the first place? Isn’t there an air cleaner before the blower motor filtering the air? Isn’t it supposed to keep this kind of garbage out of my ducts and my lungs?
Very few filters are any good at anything more than keeping large visible material out of the air. The air filters are design to keep large debris from throwing the blower wheel out of balance, not protecting anyone. If your air filter did a good job, your ducts should never need to be cleaned.
We tested in our own classroom here in Southern California the validity of the claims by manufactures about how very good their air filters are. Not surprisingly their claims turned out to be very hollow. To find out if you have a poor quality filter, even if it was sporting a high price tag, give us a call and we will come to you and test your home for particulate pollution when your system is actually running