Posted by Travis (Dallas) on May 23, 2002 at 14:33:23:
In our area we find a very wide range of services.
The carpet cleaners/duct cleaners charge a small amount and usually have a portable cleaner that can only reach a part of the ducts. They are not usually licensed to clean the air conditioning/heating equipment (evaporator coil, blower section, etc.) They charge $9-$15 per vent and it might take them about one hour.
The best Indoor Air Quality companies are licensed as mechanical contractors that can clean the air conditioning/heating equipment and use large truck or trailer mounted high velocity vacuums. They use a full source removal process and are NADCA (National Air Duct Cleaning Assoc.) certified and follow EPA rules. They might charge $35-$50 per vent plus a fee to clean the air handler and it may take them all day to do the job.
You can also check www.EPA.gov for what you might want to do.