As cooler weather prompts the switch from air conditioning to heating, many homeowners look for ways to improve efficiency and lower utility bills. A common but misguided strategy is to close the HVAC vents in unused rooms, such as guest bedrooms or formal dining areas. While this seems logical, HVAC experts warn that this practice is counterintuitive and can lead to costly damage.
Closing vents disrupts the balanced airflow your HVAC system was designed for. According to Richie Drew of One Hour Heating & Air Conditioning, the amount of air that passes through the system must be returned to it. “The key to efficiency is to have the air flow evenly through the home and the system, maintaining the right static pressure,” he explains.
Restricting this flow by closing vents increases the air pressure within the ductwork. “Contrary to a common misconception, closing vents in unused rooms can create pressure issues for your system, forcing it to work harder and potentially leading to damage,” says Micah Sherman, a virtual HVAC expert at American Home Shield.
This increased pressure puts significant strain on key components. The system’s blower motor and compressor must work harder to circulate air, which increases energy consumption and can shorten their lifespan. This strain can also cause the system to overheat, the coils to freeze, or the unit to “short-cycle”—turning on and off too frequently. Furthermore, the excess pressure can cause leaks to form in the ductwork, wasting heated or cooled air and further reducing efficiency.
For homeowners who want to control the temperature in specific areas, the recommended solution is to install a zoned HVAC system. Tim Algaushove of IRBIS Air, Plumbing & Electrical advises consulting a technician, as a properly installed zoned system allows you to manage different areas of your home independently and efficiently.
To ensure your existing system runs at peak performance without closing vents, experts recommend several key maintenance steps:
- Ensure Clear Airflow: Keep all vents open and unobstructed by furniture, rugs, or curtains. Leaving interior doors open, even in unused rooms, also helps promote proper air circulation.
- Replace Air Filters: Regularly change your system’s air filters, typically every 30 to 90 days, depending on the manufacturer’s guidelines.
- Schedule Annual Service: A yearly professional inspection will ensure coils are clean, drain lines are clear, and all components are functioning correctly.
- Check for Leaks: Periodically feel the airflow from your vents. A noticeable decrease in pressure from a specific vent could indicate a tear in the ductwork that needs to be sealed.
