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.
Blocked or insufficient return air can lead to reduced airflow from your vents. Symptoms include weak airflow and uneven cooling or heating throughout your home, with some rooms feeling much cooler or warmer than others. Homeowners should regularly check vents for consistent airflow.
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.
However, most HVAC contractors use a rule of thumb to determine the number of air vents needed. For example, for a standard residential HVAC unit, you'll generally need one supply vent and one return vent for every 100 to 150 square feet of living space.
If these air return systems are obstructed, not only will you block the proper airflow and create stuffiness in the rooms of your house, but you will have uneven cooling or heating, lack of proper filtration, and potentially higher energy bills.
For your furnace to run efficiently and your home to heat evenly, this airflow must be in balance. In other words, the amount of air that your furnace “breathes in” must equal the amount of air it “breathes out.” Cold air returns are what allow your furnace to “inhale” your home's air.
While it can be tempting to block the cold air returns for rooms you're not using to save energy or place furniture against them to arrange a room, blocking these registers is one of the most common ways to undermine your cooling and heating system.
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.
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.
Cold air returns should be strategically placed throughout your home. You'll typically find vents or grills in every room or at least in every area served by your heating and cooling system. They are often located on lower walls or in the floor and are usually larger than supply vents.
Avoid blocking air vents with pillows, furniture, plants, or pictures. When the air vents are blocked it means that heated or cooled air needs to squeeze by what is blocking it to reach the rest of the room.
Photograph 3: Closet Ventilation - The best way to provide closet ventilation is to install a small return air duct in the closet.
Return vents should be located in centralized rooms, such as larger living spaces or family rooms. These central locations allow return vents to efficiently pull air from the house and into the system. In most cases, you'll find return air vents located on a wall instead of the floor or ceiling.
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.
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.
Oversized Air Conditioners Won't Dehumidify Your Home
Without, you run the risk of water damage, mold infestation, or other problems. And, you won't be nearly as comfortable. But, an oversized air conditioner won't do the job correctly. When an air conditioner starts its cycle, it draws warm, humid air from the house.
The average cost of installing a new central air conditioner in 2024, including equipment and labor costs, is $5,750 for a 3-ton unit in a 2,000-square-foot home. On average, a new AC unit cost will fall between $3,300 and $7,800.
A return air drop replacement will run around $300-$400, including installation. In rare cases where a second drop needs to be added, the cost can be up to twice that amount.
The vents that pump out conditioned air throughout your home likely come to mind when you consider HVAC air distribution. The cold air returns are just as important, though, and making sure that they're free from obstructions is vital to keeping your entire HVAC system operating reliably and efficiently.
Due in large part to the short cycling issues mentioned above, components on an oversized heating and/or air conditioning systems are more likely to fail sooner than those on a properly sized system. As a result, you may end up having to replace your HVAC system sooner than expected.
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.
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.
Air Quality Issues
Placing a bed over a floor vent can significantly impact the air quality in your bedroom. Here's how: Reduced Airflow: When you cover a vent, you're blocking the designed path for air circulation in your home. This can lead to stagnant air in your room, which may feel stuffy and uncomfortable.