How do air leaks impact cooling efficiency and what mitigation strategies exist?

• A. Leaks reduce supply pressure and cause hotspots; mitigate by sealing ductwork, repairing joints, and ensuring proper containment.
• B. Leaks increase humidity with no impact on cooling.
• C. Leaks have no effect on cooling efficiency.
• D. Leaks are beneficial to energy efficiency.

Answer: (A)

Air leaks in the duct system push conditioned air outside instead of delivering it to the rooms, which lowers the pressure and velocity of air reaching the living spaces. That means rooms don’t get the cooling they should, creating hotspots and uneven comfort. The blower has to work harder and longer to try to meet the thermostat setting, which wastes energy and can wear out the equipment faster.

Mitigation focuses on stopping those leaks and keeping air where it’s meant to go. Seal all joints and seams with the right sealant and fix or replace damaged ducts. Use proper duct tape only for temporary or exterior surfaces, and rely on mastic or concrete-approved sealants for long-term ductwork. Repair insulation as needed, and aim to route ducts through conditioned spaces when possible so less cooling is lost to unconditioned areas. After sealing, test the system for leaks and balance the airflow to ensure each area gets the intended supply. This combination of sealing, repairing, insulating, and balancing keeps the delivered air intact, improves cooling efficiency, and reduces hotspots.