Is a return air vent necessary?

Author: Annetta Willms  |  Last update: Thursday, September 4, 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.

Is it okay to block return vents?

If your HVAC system is designed this way, blocking off a single return vent can wreak havoc on the system and lead to: Pressure imbalances that let allergens and pollutants get pulled into your air supply from unconditioned areas.

What is the point of a return vent?

As conditioned air is pushed in, the air already in the home needs a place to escape. Return air vents serve this purpose by helping to pull in the air and putting it back into the system. This is what maintains proper air pressure in a home.

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.

Does every room need a return air?

Do you need a return vent in every room? While having a return vent in every room is unnecessary, it's becoming more common in modern homes. You should ensure a balanced distribution of these vents throughout your home. This ensures that air circulates effectively, preventing hot or cold spots.

What is the purpose of a return air vent?

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.

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.

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.

Do all AC units have a return vent?

Depending on the season, your HVAC system recirculates warmed or chilled air throughout your home. Two types of vents are required: supply vents and return vents.

Can you use a wall cavity as a return vent?

Cavities (or interstitial spaces) within walls are also sometimes used as supply- or return-air pathways.

Where should return air vents be located?

They are usually located in central, larger rooms to more efficiently pull air from the home and into the system. Return air vents are often located on a wall, rather than the floor or ceiling. Air return vents play a critical role in balancing the air in your home.

How many air returns should a house have?

Having a number of return vents (preferably one in every room, but also 2 or three is far better than just one) creates regular air pressure. If you have one return vent, your house is great. Maintain the doors to every room open so air can properly flow.

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.

What room should return air ducts not be installed?

In fact, when installing return ducts it is always advisable to avoid putting them in bathrooms or kitchens. This would just simply cause the heating and air system to circulate cooking odors and moisture throughout the system.

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.”

Should return air vents face up or down?

If you have a combined heating and cooling system and need to decide between placing the return vents high or low, consider your climate. If you live in cooler climates, it might be wise to install them towards the floor, whereas if you reside in warmer areas, they should ideally be installed close to the ceiling.

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.

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.

Can I block an AC return vent?

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.

What happens if you don't have enough return vents?

Many central air conditioning systems don't get enough return air. When they don't, you can have all sorts of problems. Hot spots and cold spots throughout your home, indoor air quality problems, premature component failure… It's a long list of really bad stuff.

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.

Do I need filters in my return vents?

Maintenance Needs

Return vent filters, if used, also need regular replacement to avoid airflow issues. By properly maintaining both types of filters, you can get great airflow, reduce strain on your HVAC system, and rest easy knowing you have cleaner air.

Where is the best place to put return air ducts?

Return registers can be large and centrally located in your home, or they can be in every room. HVAC professionals recommend that each room have a cold air return vent to help with flow and temperature control. These vents are typically found on an interior wall.

What is the code for return air?

Return air openings for heating, ventilation and air-conditioning systems shall comply with all of the following: 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.

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

The cost of adding a return vent varies from $200 to $500 per vent, depending on how close the vent is to the existing ductwork. You'll need to pay more if the vent is far from the ductwork, as you'll need to install more materials.

Previous article
How often does air con need servicing?
Next article
What is the best solution to clean the inside of a refrigerator?