Should you close vents in unused rooms in Summer?

Author: Eugenia Runolfsdottir  |  Last update: Tuesday, December 30, 2025

Closing the vents doesn't do it any favors. In fact, instead of helping the air conditioner cool less, closed registers force the same amount of air through other ducts. This builds pressure in the system and makes your HVAC system work harder to distribute the air where you need it.

Which vents should be closed in the summer?

(Hint: In the summer months, open the top vents and close the bottom ones to draw out air from a higher point in the room where it's hotter).

Does closing doors of unused rooms help with air conditioning?

Opening doors/windows to the outside air will let warm, humid air in, mixing with the air already in your house, and making your AC system work harder. If you keep the house closed up the system only has to cool air that has already been cooled, which makes the system more efficient.

What happens if you block an air vent?

Blocked vents increase air pressure in your ductwork, which can create cracks and leaks. Clear vents ensure every room in your home gets good circulation so your system can work as designed. Have a piece of furniture sitting over a vent? Try using an inexpensive vent extender to direct air out into the room.

Is it okay to partially close air vents?

Unlike fully closing the vents, partially closing them still allows for proper airflow through the HVAC system. This prevents overheating and reduces pressure inside the ductwork. Because heat rises, homeowners can consider partially closing upstairs vents and fully opening those downstairs.

Rising heating costs: Can you save money by closing vents in unused rooms?

What happens if you close vents in unused rooms?

Closing HVAC vents in unused rooms may damage your HVAC system, leading to costly repairs. Your heating or cooling system produces the same amount of air regardless of how many closed vents you have.

Is it OK to partially cover a vent?

You most likely thought covering your air vents would certainly save you energy, but it does the opposite. Considering that this could damage your cooling and heating system, fractures and other damage could allow air to leave your air ducts and cost you much more in energy bills.

What happens if you cover a vent in your room?

When you close off the vents in a room, you are completely blocking airflow to that space. That's the point right? Here's why it is a problem: If that air isn't passing through the vent, it is being backed up in the ductwork, which causes pressure to build up within the system.

Does closing vents help cool upstairs?

A standard but incorrect solution is closing vents. People think that if they close vents on the main floor, the system will push more cool air to the upper floor. This strategy often results in reduced cooling performance. If you have a minimal number of vents you should not close any.

Should the vent on my AC be open or closed?

AC Vent Open or Closed: What Experts Recommend

Balanced Air Pressure: Keeping vents open maintains balanced air pressure in your ductwork, allowing your HVAC system to run more efficiently. Consistent Temperature: Open vents help achieve a uniform temperature throughout your home, enhancing comfort in every room.

Is it better to leave bedroom doors open or closed in summer?

During hot weather, keep interior doors open to help your air conditioner circulate cool air more effectively. Closed doors can trap heat in certain rooms, forcing your AC to work harder to maintain a consistent temperature throughout your home.

How to block air vent in bedroom?

Block Off the Vent: You can block the vent by placing a piece of furniture at the opening or purchasing a magnetic damper that's strong enough to stick to the steel on the wall or ceiling. Plastic sheeting can be placed over the opening as well. You can also install a vent grille filter.

How strong should air come out of vents?

If you notice a change in the airflow of your HVAC system, then you should look into calling a professional. They can come out and test your equipment to determine how strong the airflow is. How strong should air come out of vents? The recommended airflow for each room is typically 50 cubic feet per minute.

Should you close off unused rooms in summer?

In short, the answer to this question is no. Although closing off unused rooms may seem like a way to save energy on heating and cooling, it can actually force your HVAC system to work harder.

Do return air vents go up or down?

When it comes to cooling your home, return vents are best installed near the ceiling so they can draw in any hot air that has risen. Supply vents should also be placed high on the wall for better distribution of cold air throughout the room.

When should house vents be closed?

In winter, particularly in cold climates, closing crawl-space vents can help prevent cold air from entering the space and potentially freezing pipes. The simplest way to close foundation vents for the winter is to plug them from the outside with foam blocks made specifically for this purpose.

Which AC vents should be open in summer?

Hot air rises and cool air sinks. Therefore, opening the right return vents in the summer and winter significantly improves the distribution of air by your forced-air system. You'll also enjoy more even heating and cooling throughout your home. In the summer, open your high returns and close the low ones.

How do I get my AC to push more air upstairs?

Turn the Fan on to Increase Air Flow

One of the ways air conditioners remove warmer breezes is turning your thermostat fan setting to ON. When you keep the fan mode on, you increase airflow.

Does closing vents make other rooms colder?

Contrary to what most people think, closing the vents in a room doesn't divert that air to other rooms. What's actually happening is that air will leak from the ductwork, sending cool air into areas such as interior walls and attic spaces.

Can closing air vents cause mold?

Closing air vents can lead to increased pressure in the ductwork, damage to the HVAC system, mold growth, and safety hazards, such as carbon monoxide infiltration. It's best to keep the air vents open to prevent these risks.

Which way to turn the damper?

If you want to close the damper, you will need to turn the damper lever in the opposite direction of the duct. If you want to open the damper, you will need to make sure it is running in line with the flex duct. You can also adjust the damper of the furnace or air conditioner so it is partially open.

Is it bad to put a couch over an air vent?

So how much space does an air return vent need to work properly? Home Inspection Insider explains that an air return vent needs 6-12 inches of space in front of it, and recommends that you do not put large, bulky furniture like couches and bookshelves in front of an air return vent.

Does every room need a cold air return?

Having an air return vent in every room can increase the energy efficiency of a home by recirculating the air internally rather than drawing hot or cold air from outside. However, this can pose a slight staging problem since furniture and draperies should be kept clear of cold air return vents.

Where is the best place to put return air vents?

To maintain an even temperature throughout the room, return air vents should ideally be positioned higher on the walls or near the ceiling to capture the rising warm air effectively.

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