Should You Shut Vents in Rarely Used Rooms to Warm Your Home? What HVAC Experts Say

Key Points

• Closing vents in rooms that are not used can put extra strain on the HVAC system.

• Instead of lowering energy use, it may end up making it more expensive to heat the house.

• Unless the system is built for zoning, the vents should generally stay open.

Heating a home through the coldest months can cause energy bills to rise sharply. Many homeowners look for ways to keep their homes comfortable without wasting energy, especially in the rooms they use most often.

That is why some people shut the vents in empty rooms during winter, hoping to reduce the amount of heat the HVAC system has to produce. But experts say that idea rests on a misunderstanding of how modern HVAC systems operate.

We asked HVAC professionals what really happens when vents are closed in unused rooms and whether the practice helps the system or the utility bill.

Meet the Expert

Is It a Good Idea to Close Vents in Empty Rooms?

Many homeowners assume that closing vents in unused spaces will lower energy costs and reduce wear on the HVAC system. That may have been possible with older systems, but modern HVAC equipment is designed to distribute air throughout the entire house.

TJ Laury, an HVAC technician and president of Ben’s ProServ, says that closing vents creates back pressure in the ductwork, which forces the furnace to work harder to push air through the vents that remain open.

In other words, the system ends up working harder than before.

“Think of it kind of like a cul-de-sac,” Laury says. “Instead of being able to drive through the street, you have to circle turn the car around. Closing the vent creates a traffic jam of sorts.”

For that reason, vents in an unused room should not be closed unless the HVAC system was specifically designed for zoning.

Zoning systems divide a home into separate areas with individual thermostats and motorized dampers that regulate heating and cooling independently. Most homes do not have this setup, so keeping vents open is usually the better choice for efficient heating.

Can Closing Vents Save Energy?

“With a modern system, closing vents in unused rooms is not an effective energy-saving method at all,” Laury says. “Your system doesn’t adjust for closed vents and will still produce the same amount of heated air. Closing vents creates an imbalance that can potentially lead to needing repairs in the future.”

Elizabeth Shavers, general manager of HVAC & Plumbing at Oncourse Home Solutions, adds that steady airflow and balanced distribution are essential for heating efficiency, and isolating rooms from the system does not improve that balance.

Ways to Keep Your Home Warm and Cut Heating Costs

Although closing vents in unused rooms will not help reduce energy waste, there are several other ways to stay warm while using energy more efficiently.

Laury and Shavers suggest the following tips to improve home heating efficiency during the winter:

• Smart thermostats let homeowners adjust temperatures based on routines, actual usage, and whether anyone is home, away, or sleeping.

• Dropping the temperature by 7 to 10 degrees for eight hours a day, such as when you are away or asleep, can save about 10% on annual energy bills.

• Good insulation in crawl spaces, attics, and exterior walls helps keep heat inside so the system does not have to work as hard.

• Sealing air leaks around windows and doors keeps cold air out.

• Air filters should be replaced every 30 to 90 days, and more often if you have pets that shed heavily.

• Keeping vents and interior doors open supports more even heating and better airflow.

• Using a humidifier with your heater can make the air feel warmer because moist air holds heat better than dry air, which may allow for lower thermostat settings and lower energy use.