When the combustion air duct is connected directly to the return plenum for a furnace, the blower fan on the furnace pulls outdoor air in to the return plenum. To supply this air to the furnace room, ...

To fully understand how to install a high-velocity HVAC system, one must know what it is and what it does. Basically, it is a small duct, high-velocity airflow, heating and cooling system designed to ...

[Editor’s note: When we last visited with lead installer John and his helper Charlie (The NEWS, March 5, 2007), they had just learned the hard way that there’s a lot more to sealing ducts than just ...