You can usually spot return vents on your walls, ceiling, or floors. Look for a white grille without shutters to spot an air return vent. These vents will typically integrate seamlessly into your home.
To identify a return vent, take a piece of paper and hold it up to the vent. If the paper is drawn towards the vent, then it's a return vent. Return vents are usually larger than supply vents, and they usually don't have adjustable slats to direct airflow since the air is going into the ducts instead of out.
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. If you notice a significant drop in air pressure or uneven temperatures, it could indicate return air issues.
Return air vents are usually found in the lower wall of a room or hallway. Ideally, your return air vents and supply vents should be on opposite sides of the space. Otherwise, you may be pulling some of the heated or cooled air back into the system before it has a chance to circulate.
How Are Supply and Return Vents Different? The biggest difference between supply and return vents is the direction in which the air flows. In a supply vent, the air flows out of the ductwork. In a return vent, the air flows into the ductwork.
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.
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.
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.
You can identify supply vents in your home by turning the system fan on and holding a piece of paper in front of the vent. If air blows out, it's a supply vent. Return air vents connect to your return ducts, and they're typically larger than supply vents.
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.
Parts of Your Home Are Hotter or Colder
If there's not enough return air, your living room can be 10℉+ warmer or cooler than, for example, the bedrooms.
We've seen how it can create safety hazards, mess with your home's heating and cooling, and even damage your bed. Blocked vents can cause fire risks, poor air quality, uneven temperatures, and moisture buildup. Instead of covering vents, try rearranging your furniture or using vent deflectors to direct airflow.
Common Issues with Return Ducts: Clogs and Leaks
You can generally identify a blocked air duct by a distinct drop in heating and cooling efficiency, increased energy costs, and occasionally a musty, dusty smell throughout the home.
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.
While return vents don't always require filters, adding them provides additional filtration, improving indoor air quality and keeping dirt and debris out of your system. However, there are pros and cons to consider.
Dirty filters, leaky ducts, and poor insulation can cause cold return vents. Leaky ducts often cause cold air to blow even after cranking the heat up. 20-30% of air, especially hot air, is lost because of leaky ducts. Cracked, holey ductwork needs sealing or replacement.
You can usually spot return vents on your walls, ceiling, or floors. Look for a white grille without shutters to spot an air return vent. These vents will typically integrate seamlessly into your home.
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.
The International Mechanical Code requires a duct smoke detector in the return for units over 2000 cfm and requires a detector in the supply duct for systems over 15,000 cfm. Many designers require duct detectors in the supply and return in an attempt to meet both conflicting requirements.
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.
Ideally, there should be a temperature differential of around 14° to 20° Fahrenheit between the incoming air and the air being blown out by your air conditioner. This means that if the air entering the system is 75°F, the air coming out of the vent should be between 55°F and 61°F.
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.
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.
Signs of an air duct clog include: One room in your house is hotter than all the others. Dirty air coming from vents. Unusual spikes in electric bills.
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.