Should the air vents in empty rooms be closed during the summer? What they are for and what experts say

Closing the vents in empty rooms during the summer is a mistake, according to climate control experts. Far from reducing electricity use, this practice can cause mechanical failures in the air conditioning system and raise the electricity bill.

HVAC systems are designed to maintain balanced airflow throughout the home, measured in cubic feet per minute (CFM). Altering that balance directly affects the equipment’s performance and lifespan.

What air vents are for and why they should not be closed

Vents work as air entry and exit points: return vents extract warm air and supply vents replace it with cool air. Both work together to maintain the temperature throughout the house.

When a vent is closed, air continues moving through the duct and, with no outlet, creates positive pressure in the system. That increase can lead to failures in the fan motor and compressor —the equivalent, according to specialists, of a blocked artery.

What happens to electricity use if vents are closed in summer

Closing air vents in empty rooms does not lower the bill: the extra pressure forces the motor and compressor to work harder, which increases amperage use and lowers the unit’s efficiency.

The alternative recommended by HVAC specialists is butterfly dampers, installed in the main duct. They act as if that branch did not exist, without changing the system’s overall pressure. Their installation requires a certified technician.