HVAC uses of flexible air duct have grown exponentially over the last two decades, all over North America. Contractors and installers say they like it, and some find it indispensable. It has changed ...

In David Monson’s region of New Hampshire, the Armstrong Duct, Vent, Hearth and Home operations lead says he often works on what he calls “Brady Bunch” houses – homes built in the ‘60s, ‘70s and early ...