This is a great site. I am glad finding you guys.
My first house was a new construction. I started modifying the regular air filter and placing in behind the return grille to keep the duct work clean. Although that is the only new construction I bought, I have been modifying the air filters from Home Depot for my return grilles for more than 10 years. Recently Ive seen many duct cleaning ads and would like to think placing an air filter at the return grille is a good idea, especially for the new constructions.
Id love to read your thoughts.