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Can I Save Money on Cooling by Closing Room Vents?


Homeowners sometimes look at the louvers on the air vents in the rooms around their house and think, “Can’t I just shut that vent so no cool air is sent into this room? That at least means I’m not wasting extra money cooling it.”

This isn’t how vent covers or your air conditioning system works. In fact, shutting room vents can create much worse problems that may lead to you needing to call us for air conditioning repair in Fresno, CA. There are other ways you can save money with your air conditioning system, as well as ways to limit cooling to rooms.

The Problem With Closing the Vents

First, the vent louvers aren’t designed to seal off the vent opening. No matter how much you try to close them, some air will still be able to get through. The purpose of the louvers is to direct how the air enters the room, not close the vent.

Second, blocking the vent in any way affects the pressure inside the ventilation system. The air conditioner and the blower fan do not work less because a few vents are blocked. In fact, they will most likely work more. If the blower fan has a single-speed motor, blocking the vents will greater more resistance against the fan. The motor will continue to run at the same speed, but it will cause the air pressure inside the ventilation system to rise. This is a leading cause of leaks in ductwork. The motor will also run longer and drain more energy.

For a variable-speed fan, the resistance in airflow from blocked vents will cause the fan to drop to lower capacity, and this will cause a decline in air pressure throughout the ventilation system—and subsequently, a drop in comfort. Another possible effect is the evaporator coil will freeze over. If the blower fan is sending less air over the coil, it will leave the coil too cold and allow it to freeze.

The bottom line is that shutting or blocking room vents won’t save money and will probably end up costing you more in comfort and repairs.

Zone Control Options

It is possible to control which parts of your house receive cooling (as well as heating) and which don’t. It’s called zone control. If you have a standard central air conditioning and heating system with ductwork, zone control uses dampers inside the ducts to close them off and a variable-speed fan and multi-stage compressor that adapts to closed zones so the system uses less power and doesn’t create pressure changes. It is usually best to have zone controls put in as part of a new system installation.

Zone control is also a basic part of ductless mini split systems. Because these systems don’t use ducts but instead send air through different wall-mounted units, they can have cooling/heating shut off to individual rooms by turning off the room unit.

If you’re interested in zone control systems or you want options to lower your cooling costs, speak to our experts. We’ll be glad to help you out.

Contact Purl’s Sheet Metal & Air Conditioning. Uncompromised Quality & Customer Service Since 1952.

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