Static pressure is one of the most useful measurements HVAC contractors rely on when diagnosing airflow and performance problems. A heating and cooling ...

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, ...

As air moves from a supply plenum or main duct into a takeoff it changes direction. Airflow has a hard time making turns at high rates of speed, just as we would driving down the interstate. When we ...

Many in our industry believe the duct material used in an installation determines how well the HVAC system moves air. Because of this mentality, flexible duct often gets a bad name. The issue isn’t ...

Ask any bug: There's no place like a warm crawl space to spend the cold winter months. Why huddle beneath some freezing leaf when you can snuggle under a house that a human pays to heat? Of course, ...

Engineers at a consulting company used fluid-flow software to discover why the air in a paint booth was just swirling around instead of exiting with the fumes. Clint Hardie, principal at Technicon ...

All questions and answers are based on the 2017 NEC. Underlined text indicates a Code change. Q. What are the Code rules regarding wiring installed in ducts specifically fabricated for environmental ...