Robert Ballard

We installed Certee Duct Board in our personal residence in 1977 and used a "wild return" (no duct board, just air return back through a CMU plenum, which contains 3 Heatlator fireplaces) back to the original water-to-air York heat pump unit located in the basement with updraft airflow....We never have had any problems with this system...never any respaitory issues, never any mold issues.....The duct system was sized per heat loads as outlined in ASHREA and ductalator.....Corners of ducts were "cut" using the proper cutting tools for duct board, then stapled and then seal with aluminum tape (not duct tape)....System contains air turning vanes (made of fiberglass) at square turns and transistions pieces to keep the proper air flow velocities....The air supply system was constructed and installed and balanced according to Certee Installation Manual, ASHREA and NABB (balanced)....As far as I can tell the duct board material has not "thinned any" and air has been flowing thru it for 33 years....This is my experience and my opinion using duct board!!!!! Bob...PE since 1970