Where Should Cold Air Returns Be Located In Basement?

Every room in your house should have the same temperature. You can achieve this by ensuring at least one cold air return on every floor. However, the basement air is usually colder than the other rooms in your home. Therefore, you should place a cold air return in an open place. This can be on the basement floor or even the wall.

You can place a cold air return on the basement floor or wall. If you place it on the floor, it will suck away all the cold air near the floor. The air return will then draw down the warm air from the return air ducting near the ceiling. If you place it 90 degrees through the wall, it will draw warm air from the hallway or furnace room.

Do you Need an Air Return in the Basement?  

You need an air return in the basement. Hot air heating systems function when there is an air return in every room of the house. Having an air return in every room ensures the air circulates better.

Also, having a cold air return in every room ensures a uniform temperature around the house. This is because the heated air from the heating system mixes with the cool air to reach the ideal temperature.

Also, although you do not use your basement as a living space, you use it in other ways. For example, many important devices are in the basement. Some of the devices are the water heater, furnace, and others.

These devices need to stay warm and in good condition. Installing return ducts in the basement ensures that the temperature in the basement is ideal. Thus, these devices remain in excellent working condition.

How do you Install an Air Return in the Basement?  

It is easy to install return ducts in your basement if you understand the process.

Here is a breakdown of the steps you should take when installing return ducts in your unfinished or finished basement. You may have to install them in an unfinished basement to move out stale air.

  1. Determine the number of return air vents you need for the basement. If you are unsure about this, contact a certified HVAC technician for assistance.
  2. Decide where you would like to put the return airs. You can position them on the floor or the wall. They need to be in an open place to facilitate airflow. Many people prefer installing return airs on the wall to the floor.
  3. Measuring the centerline. You should always measure the centerline from the side closest to the parallel wall. Once you have done this, you should determine the width of the duct.
  4. Use the size of the duct to mark. Measure half of the width of the duct from the centerline. It is always good practice to add an inch to the half distance. This ensures that the studs are appropriately spaced.
  5. Installation. At this stage, cut the studs and install the ducts. Again, remember to fill the spaces between the studs.

How Many Air Returns do you Need in the Basement?  

There is no specific number of air returns that you should install in your basement. The number of air returns you should have in your basement depends on many factors.

The most important factor is the size of your furnace. The bigger the furnace, the more return vents you need. This is necessary for the HVAC system to work properly.

Based on space, you can estimate the number of air returns you need in your basement. A standard-sized air return vent has a CFM capacity of 300. This means that the vent can suck and move 300 cubic feet of air every minute.

Ideally, you should have one air return for every 300 square feet. For example, if your basement measures 400 by 400 feet, its area would be 1600 square feet. Thus, you will need about 5 air vents to maintain the proper flow of air.

It is usually difficult to estimate the actual number of vents for basements. This is because the air in basements is usually heavier than elsewhere. If you are unsure of the right number, you can seek expert advice from a trained HVAC professional.

Is it Possible to have Excess Air Returns in the Basement?

In theory, it is impossible to have excess air returns in the basement. This is because air return vents do not naturally suck the conditioned air from the house.

Instead, they work by maintaining the air pressure in the house. If there is too much air from the supply vents, the return air vents automatically give the conditioned air an escape route. They channel the air back to the air handling unit, thus managing the pressure difference.

If, for example, you place too many return air vents in the basement, the returning air will balance out between them. This process will maintain the pressure difference between the living space and the outside.

Similarly, an air return cannot be too big. However, in some extreme cases, this can happen. A common example is when you have a closed room with negative air pressure.

In such a case, the return vents fail to maintain air pressure in the room. Therefore, if you have negative pressure in a room, the air returns will function as if they are too big for the closed room.

Should I Install a Return Air Duct in Every Room?

where should cold air returns be located in basement

You should install a return air duct in every room. This includes even the basement. Ideally, you can install even more than one return duct in a room. It all depends on the size of the room and your furnace.

Your HVAC system works as a closed ductwork system, vents, and an air handler. It has components that cool and heats the air separately. It also has vents that supply air and those that return it. The system does not take in fresh air from the outside.

Instead, it simply recycles the air through return air ducts. Having return air ducts in every room optimizes airflow in the house. It also helps to keep the air fresh in every part of your house, including the upper floors.

You should install return vents in all rooms to maintain pressure. Your HVAC system works well when the pressure difference is zero. If there is positive pressure inside the house, warm air leaks out.

If there is negative pressure, the system does not function properly also. The supply air amount is the same as the cold air return. Ensure every cold air return in all rooms is open.

Can a Flexible Duct Replace a Cold Air Return?

Yes, a flexible duct can replace a cold air return in your air conditioning system. A flex duct is made from flexible materials like PVC and rubber. They also come with fiberglass insulation.

You may prefer them to metallic ductwork because of their flexibility. If you would like to run the ductwork through multiple bends, it may be good to use a flex duct.

But you need to consider a few important issues before using a flex duct. First, metal ductworks are usually insulated to R12. Flex ducts hardly reach this level of insulation.

It would help if you improvised by wrapping them separately with fiberglass. You may also use aluminum to insulate your flex ducts. This will help them withstand the heat from hot air.

Also, it would help if you kept the dust off your flex ducts. If dust enters your system, it will accumulate inside and cause problems. You should get the best filters for your system. It would help if you also replaced them as soon as they become full of dust.

How Far Should the Air Return be from the Supply?

The air return should not be any close to the supply. If the return registers are close to the supply ones, you may not experience the comfort of fully conditioned air.

The return registers collect the air and take it back to the system. The supply registers distribute the conditioned air around the house. Thus, the conditioned air needs time to circulate in the whole house.

If the two types of vents are very close, the air may escape without circulating properly. Thus, keep the return vent far away from the supply registers.

You should follow this placement strategy if you are remodeling your house. Also, it is a good idea to place the supply registers close to the window. The hot air that the supply vents give off usually creates a buffer zone.

This will keep the area slightly warm. Thus, the cold air from outside cannot interfere with the temperature in your house.

How does Cold Air Circulate in the Basement?

cold air return placement

Cold air circulates in the basement via a convective method. Air enters the basement through the window. The temperature of the airdrops because the basement air is cooler. The air then begins to rise to the top floors of the house to replace the warm air that leaves via the windows.

You can speed up the convective process by placing a fan near the window upstairs. The fan will speed up the process by pushing warm air out. This creates space for cool air from the basement to rise.

Where Should Cold Air Returns Be Located In Basement FAQs 

Where should my Cold Air Returns be Located?

Your air returns should be on the wall of the floor. They should be far away from the supply registers. This will give the conditioned air time to circulate in the house. The conditioned air will then get back into the system through the return vents.

Where should my Vents be Placed in the Basement?

Your vents should be placed either on the wall or the floor. The ductwork in the basement is on the roof. This placement will allow warm air to move around the basement and cool air to be sucked.

How do I Install Air Return Vents in my Basement? 

You should first decide the number of vents you need in the basement. Next, it would be best to decide where you would like to install them. Once you have done these, measure the centerline and mark the width of the ducts. You can then cut the studs and install the ducts.

Should Air Return Vents be High or Low? 

It would be best if you had high return registers for the effective flow of air in our living space. Having high return registers helps easily move the hot air that rises towards the ceiling. Cool air is heavier than warm air. This is why cool air tends to move to the lowest level in the room.

Will Adding a Cool Air Return in the Basement Help with Summer AC Power Usage?

Adding a cool air return in the basement will not necessarily help with summer AC power usage. However, you need the cold air return in the basement to slightly warm the area.


It would help if you had cold air return vents in the basement. Although you do not use the basement as a living area, you may spend some time there. Also, there may be vital devices like the water heater and heat exchanger in the basement. The stale air in the basement is undesirable.

Having one or two return vents in the basement will make the air inside the place fresh. The number of return vents that you can place in the basement depends on the space.

Ideally, install one cold air return vent for every 300 square feet. Also, you can install the vents on the wall or floor. However, make sure you do not suck cool air from the same room as the furnace.