Should you close AC vents in rooms you’re not using?

September 9, 2020   By Terri Williams

Should you close AC vents in rooms you’re not using?

We’re all looking for ways to cut utility costs and save money. And since heating and cooling your home is a major energy expenditure, it makes sense to evaluate all of the possible ways to reduce energy consumption. And especially in Texas, your home’s AC vents have a big job to do.

However, not all of those ideas will actually save energy and money. For example, some people believe that closing the AC vents in the rooms you’re not using can result in energy savings.

And at first glance, that makes sense. If, for example, you’re sitting in your living room all day, why should you cool and heat all of your bedrooms and other areas of the home? However, this is one of those recommendations that doesn’t ring true.

“Contrary to popular belief, closing AC vents in rooms that aren’t in use isn’t a good idea,” according to Marla Mock, VP of Operations at Aire Serv. “While the idea may be to close off one area in order to make another area more comfortable, surprisingly, doing this can cause damage to your HVAC system, increase the energy needed to cool your home, and in turn, cost you more money.”

What’s the verdict on closing your AC vents?

Here’s the problem: when you close air vents in rooms in your home, Mock explains those rooms will actually become hotter – which in turn will increase your home’s overall temperature.

“Unfortunately, most home HVAC systems are not designed to interpret these differences in temperature, meaning that despite your choice to close vents, your HVAC system will continue to try to cool the whole house,” Mock said. And this means that you’ll be causing your system to work even harder to try to lower your home’s overall temperature.

“Further, reducing airflow to one room increases air pressure directed elsewhere throughout the duct system,” Mock explains. “Because your home’s HVAC system is designed to regulate the temperature of the entire house, when ducts are closed, this pressure can build up and may eventually cause damage to your ducts or cooling system.”

So, you actually want your AC to flow freely from every possible source. In addition to not closing vents, this means that you should ensure that they’re not being blocked unintentionally. For example, don’t place furniture, like sofas, dressers, and chairs, over floor vents, and don’t let heavy floor drapes cover them, either.

If this type of scenario is unavoidable, consider getting an air vent deflector (also known as an air vent diverter). “It is usually made of plastic, and fits over the air vents in your home,” Mock said. “You can adjust it in different directions, depending on your air redirection needs.”

Other ways to save on energy bills

Another energy saving step is to make sure that air isn’t escaping your home. When hot or cold air leaves through your windows and doors, your unit has to work harder to maintain the desired temperature. According to the Department of Energy, you could save 10 to 20 percent on your energy bills just by sealing holes and cracks in your windows and doors.

And all you need is a caulk gun and either latex or silicone-based caulk cartridges (or tubes). Then remove the old caulk (using a putty knife or screwdriver), clean the area, and let it dry thoroughly. Cut off the top of the caulk at a 45-degree angle. And then hold it at a 45-degree angle and apply the caulk. If you make any mistakes, be sure to clean them up immediately, before the caulk dries.

You can caulk (or install weatherstripping) around windows and doors, but also along other areas where air could be escaping. For example, the holes in the wall where your plumbing enters your home are prime places for air to escape (and for pests to enter).

Other air leaks can occur around your electrical wiring. The leaks can be on the walls, ceilings (for example, around recessed lights), floors, and the soffits over your cabinets. Other places to check for air leaks include the flue or chimney shaft, and throughout your attic.

If those holes are too large for caulk, expanding foam sealant is a better option. Regarding outlets and switch plates, you can install foam gaskets behind them.

And here’s one hint that may help you determine if you have an air leak: if you have unexplained dirt spots on your carpet or ceiling, it could mean there’s an air leak in that area.


Terri Williams is a freelance journalist with bylines at The Economist, USA Today, Yahoo, the Houston Chronicle, and U.S. News & World Report. Connect with her on Twitter or LinkedIn.