S.K.
A.,
We have had our air ducts cleaned and it does make a difference. You could get several estimates, but I highly recommend Steve at Amistee Air Duct Cleaning. ###-###-####. or 877-349-8877, www.amistee.com. They are reliable and reputable. There are great testimonials on their web site and lots of great resources and information about duct cleaning and how it makes the home healthier. Good luck.
S.