Should AC Vents Be Open Or Closed In Summer & Winter?

When the seasons change, your ventilation needs to change as well. The last thing you want to worry about is the effectiveness of your home ventilation system and whether or not to keep your AC vents open or closed. Knowing the best way to regulate your vents during the summer and winter will help ensure that your home is receiving the best interior maintenance possible.

AC Vents Explained – Supply Versus Return

Understanding how AC vents work is vital to ensure you get optimal performance out of your unit. Central heating and cooling systems process air by sucking it in the return vents and blowing it through the return registers. The return vents make sure that the system conditions air from inside the house and the indoor air pressure remains equalized.

The location of the return vents depends on if the system is heating or cooling the air. If your system does both, then it’s important to split the difference in functionality. This should be determined on whether it’s more difficult to heat or cool the home.

As the hot air rises, the cool air sinks. In the summer, it’s crucial to open your high return vents and close the low ones. This action allows warm air to be taken to the AC coils for cooling. During the winter, you should open your low returns so that the HVAC system can pull out the cold air from the lower floor.

Many two-story homes also come with supply vents. You will want to monitor these vents when the weather changes to make sure the flow of hot and cold air in your home is functioning properly.

Close Up View of a Ventilator

Why Is It Not a Good Idea to Close Central AC Vents?

Closing the central AC vent in an unused room would be the best thing to do to conserve energy and save money. This can also cause damage to your HVAC system long term. Here are some things to consider when trying to determine if you should close central AC Vents.

Places Strain on Your Air Ducts

When you close one or more air vents, your system uses more pressure, putting strain on the ducts. While the strain may not cause a problem immediately, continuing to do this can cause more problems in the future. It’s best to avoid this altogether.

Increases Energy Bills

When you close an air vent, it causes your system to work harder. It uses more pressure to push the air to other rooms of your home. The added stress causes more air to flow and, therefore, increases your bills. So, while you think you’re saving money by not cooling a room or two, you’re doing the opposite.

Makes You Less Comfortable

If you’re closing an air vent, you’re going to have rooms with different temperatures. This can make you feel uncomfortable when moving from one room to another, especially when it’s very hot or cold outside. No one wants to feel uncomfortable in their home, so you should keep them open.

Potential to Damage Your AC System

Not only can the added pressure cause your energy bills to rise, but it can also cause damage to your AC system. It can cause the system’s cooling coils to freeze, which can make the compressor work less or break. If this breaks, you’ll be spending more money on repairs, and they may feel too warm if it’s hot outside.

Interior Walls Aren’t Insulated

Since the interior walls aren’t insulated, the heat from the room with restricted airflow will seep into other rooms. It’ll move under the doors and through the walls, not keeping the other rooms as cool as you think they would be.

Closing Vents Restrict Airflow

Static pressure is resistance to airflow in a heating and cooling system’s components and ductwork. Closed vents increase pressure and restrict or stop air pressure in your home. Closing interior doors can often generate the same response. The exception is when your heating and cooling systems are separate, and you added central heating to the house later.

Summer vs. Winter – HVAC Venting Care

Since hot air rises and cool air sinks, this impacts the overall cooling of your home. Opening the return vents can help with air distribution during both the summer and winter. It would be best to open the high returns and close the low returns for the summer.

This allows hot air to be sucked out of your room and to the coils to cool. When the system removes the hot air, it gives the cool air more space to distribute evenly. The system won’t remove the hot air if you open the lows instead.

During the winter, you’ll want to open the low returns. This allows the system to remove cold air to keep your place comfortable.

Window AC Unit Vents: Should They Be Open Or Closed?

Depending on the season, opening or closing your window AC units vents can be a good or bad idea. When you leave the ducts open, fresh air enters the room. If you want fresh air, then you need to leave it open.

The main issue with this is the weather outside. If it’s warm out, you’ll want to keep the window AC vents closed unless you want to let hot air into your home. During the winter, it’s the opposite.

Should I Close Air Vents In Unused Rooms?

You shouldn’t close air vents in unused rooms. It’s not a good idea for many reasons. Doing this can cause damage to your AC system, release carbon monoxide into other parts of your home, and cause the temperature in your home to vary.

Closing vents in unused rooms means that your AC system is putting more pressure onto the ducts to push air out. This can cause it to break, and then you won’t feel as comfortable in your home. Since the interior walls aren’t insulated, the used rooms won’t be as cool as you would expect them to be.

Air Vent Filters

People Also Ask (FAQ)

Commonly asked questions regarding opening/closing AC vents.

Should all vents in the house be open?

Yes. Even if you’re tempted to close one or all of them, you shouldn’t. It can cause problems like raising your energy bill, damaging the ducts, discomfort, and more.

Does closing AC vents make other rooms colder?

Not really. When you close vents to make another room cooler, you may feel a temporary difference in how colder the room is, but it won’t last since the interior walls aren’t insulated; it won’t last. That hot air from the closed vent rooms will leak to the other rooms and cause them to feel warmer.

How do I get more air flow out of my vents?

There are a few ways to get more airflow. You can schedule maintenance to see any issues, clean the air ducts, turn on ceiling fans, or get a ventilator.

Can I close AC vents in the basement?

You can if you want. If you do this, you should make sure you reopen them in a day or two at the latest. Also, when you do this, you shouldn’t close any of the other vents in the other levels of your home.


AC Units are one of the most useful inventions for comfort and health. But even they require some basic care. Following the simple rules above helps keep your AC performing at its best for years to come.

Simple adjustments to your habits can take pressure off of your HVAC unit and extend its life so you can enjoy the comforts of having warm and cool air in your home whenever you need it.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.