How important are return vents?

Author: Marielle Roberts  |  Last update: Tuesday, April 8, 2025

Air return vents are essential to your HVAC system. They are what pull air from the home, return it to the system, filter it, and help maintain comfortable temperatures throughout your house. They also help remove excess moisture from the air, thus preventing your home from feeling muggy or dank.

What happens if you don't have a return air vent?

A lack of return air can cause your HVAC system to overheat, leading to frequent shutdowns or overheating warnings. This overworking can also result in the air conditioner blowing warm air, especially in high temperatures.

How important is the return air vent?

Your AC's return air vent is a critical component of an HVAC system and serves several purposes. Not only do return air vents maintain your home's air pressure and filter out debris, they can also serve to save you on energy costs and expenses, which is important here in hot and humid Gainesville, Fla.

What happens if you block the return air duct?

Reduced efficiency: Your HVAC system will work less efficiently if you block a return air vent. This will make the units use more energy and will raise your utility costs.

Does every room need a return vent?

Instead, there should be at least one return vent in every room, with two or three being ideal. If your house has only one return vent, this is not a problem — make sure to keep the doors open in every room so the air can circulate properly. Make sure there are no furniture, draperies, rugs, etc. blocking return vents.

Air Flow: Supply and Return in your Home

Is it OK to close vents in unused rooms?

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.

What happens if a room doesn't have a cold air return?

If there's not enough return air, your living room can be 10℉+ warmer or cooler than, for example, the bedrooms. Not enough return air in summer can cause rooms close to the central unit to be cooler and those farther from it to be warmer. In winter, rooms farther from the furnace can be too cool.

Can I close off a return vent?

You should never close your HVAC return vents, but supply vents can be adjusted to improve home comfort. In this blog, the trained professionals at Damiani's Comfort Design explain the strategy behind opening your supply vents and the dangers of keeping your return vents closed.

Can I add a return vent to existing ductwork?

You can add a vent to existing ductwork if your AC can handle it. This can provide comfort in rooms not served by your HVAC system. It can even improve indoor air quality and increase your home's resale value.

Is it OK to partially block a return vent?

You should never block your air return vents. Period. However, if you're looking to keep your home cooler in the summer, you can try closing lower supply vents and keeping upper ones open, allowing cooler air temperatures to come in from above and sink throughout your house.

What are the rules for return air ducts?

1. Openings shall not be located less than 10 feet (3048 mm) measured in any direction from an open combustion chamber or draft hood of another appliance located in the same room or space. 2. Return air shall not be taken from a hazardous or insanitary location or a refrigeration room as defined in this code.

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.

Will adding a return vent help with cooling?

Guess where that air goes, that's being sucked into the Return Air vent. It goes back to the air handler, into a large plenum (box), mixed and joined with the Return Air from the other rooms. Blending the air together helps eliminate the hot/cold rooms and zones in your house.

How do you know if you don't have enough return air?

Low airflow can make your ears hurt in one room compared to another. Use a barometer to measure the pressure in the kitchen, living room, bedroom, and other rooms in the house. If you notice different pressure measurements throughout the house, this is a sign there's not enough return air.

How much does it cost to add a return air vent?

Adding a return air vent will cost homeowners $350 per vent on average, depending on the vent size and duct material. A professional can assess the right duct material you need for your home and can give you an accurate estimate.

Is return air necessary?

The Importance of Cold Air Returns

The cold air return vents distributed throughout your home ensure that air efficiently moves in a continuous loop through your HVAC system. Without cold air returns, your system would struggle to pull in the air it needs.

Does every room in the house need a return vent?

Does Every Room Need Air Return Grilles? While it is a myth that air return grilles are required in each and every room in the house, it is definitely necessary to have more than one of these grilles installed at strategic places in the house. The most important place to have these would be the bedroom.

Is it better to have air return high or low?

Up High: having an air return higher up on a wall will be better at sucking in hot air that rises. Making it more efficient at transferring this hot air back into your system to repeat the cooling cycle. Down Low: if you have your air return lower on your wall it will function better as a cold air return.

How many return ducts should a house have?

One per room is ideal, but placing two or three in central locations can provide enough air circulation to maximize the energy efficiency of your HVAC and optimize indoor air quality, so your family stays healthy. If your home has multiple stories, you should have at least one return air vent per floor.

Can you put a bed over a return vent?

Dropping a mattress directly onto a floor vent will completely restrict the airflow and prevent the HVAC system from heating or cooling the space. This, in turn, can cause the HVAC system to work overtime, leading to premature wear and tear.

Should return vents be open or closed 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.

What happens if the return air vent is blocked outside?

Broken heating or cooling elements

On the heating side, if you block off the return, the exchanger can overheat. “In extreme examples, it can crack and fail,” Smith says. “They're all designed to have that proper airflow and bad things can happen when that's thrown out of whack.”

How to increase return air flow?

By installing more return vents throughout your home, they can trap the air and remove it, improving air circulation. A drawback with this method is that your ductwork needs enough space to support additional vents. Smaller homes that can't add more vents need to pursue other options.

Can I put furniture in front of a return 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.

How to cool a room without a return vent?

-Put a louver in the door. Not great for acoustics, and may look goofy. -Install a transfer grill. In the wall above the door, or anywhere in a wall that's between the bedroom and a room with a return duct, cut a hole and install a register grill on both sides of the wall.

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