Do my ducts leak excessively? Most likely. ASHRAE says that 75% of all ducts in
commercial buildings leak 10-25%. (That’s 200-700% higher than ASHRAE’s recommended standard of 3%!)
To assess your situation, check those which apply:
Evaluate ductwork construction:
___ Do they use slip-and-drive connections on metal ducts?
___ Do they use sheet rock, masonry for air distribution or ventilation shafts?
___ Are there faulty or missing gaskets (can you feel air leaking)?
___ Are there visible holes or gaps at corners, seams, connections or hangers?
___ Is there pressurized external insulation – aka “the air mattress effect”?
Look at the rooms at the end of the hall (ie, far away from fan):
___ Is there poor air flow in these rooms?
___ Are these rooms too cold in the winter or too hot in the summer?
Look for uneven air distribution / pressurization issues within the building:
___ Do some areas have excess air flow, while others areas are insufficient?
___ Does airflow delivered vary upon time of year (summer vs. winter)?
___ Are there issues with doors being difficult to open or close?
___ Does the bathroom exhaust grille fail the “two-ply toilet-paper test”?
Ask about occupant complaints:
___ Are there heating or cooling complaints?
___ Are there complaints about moisture, mold, odor, or air quality?
If practical, ask about the fans (the #1 sign of excess energy consumption):
___ Are they unable to setback the air handler at night or weekends?
___ Do fans commonly operate at excessive speeds – ie wide-open?
___ Have motors, pulleys, or sheaves been replaced to provide more airflow?
If you check two or more there is a 90% chance your ducts leak excessively, and cost you money. The US Department of Energy says that sealing ducts is the most cost effective way to reduce HVAC costs. You can save money, with a good payback, while addressing other issues at the same time.