Common Issues with Return Ducts: Clogs and Leaks You can generally identify a blocked air duct by a distinct drop in
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.
Because the return air vent works to suck air from a room and back into the ducts, you can try this simple test to see if it is working: take a tissue or thin paper and hold it in front of the return air vent, about 6” away. If the paper is being pulled toward the vent, you know it is doing its main duty.
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.
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.
More Air Is Blowing In Rooms Near the AC Unit
A telltale symptom of an undersized return air duct is if the room closest to the air conditioner has more airflow than rooms farther away from it. That's because air pressure is high near the unit. But the farther you go, the lower it is.
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.
Limited Return Air
You will want to check and ensure that the return vents throughout your vent are not blocked. If these vents are blocked, it can lead to a lack of air being pulled back into your system.
An anemometer, a test instrument that measures air velocity is used to determine the average airspeed in the duct. Then the average feet per minute is multiplied by the area of the duct in square feet to determine the airflow moving through the duct.
Ensuring your cold air returns can do their job effectively involves a few simple practices: Regular Cleaning: Dust and debris can accumulate, reducing efficiency. Vacuum or dust them regularly. Keeping Them Unobstructed: Be mindful of furniture placement and avoid covering these vents.
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.
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.
Return air ducts must be sealed and unobstructed — Sealing return air ducts is just as important as sealing supply ducts. Sealing all duct section connections with mastic, a specialized rubbery sealant, or with metal tape prevents air leaks.
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 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. The blockage usually comes over time, by a buildup of dust and debris that just accumulates until it begins choking the system.
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.”
If your air handler is running but not blowing air, there are two likely scenarios: either a broken AC blower belt or an issue with the motor itself. If the air handler is humming or buzzing but not making the mechanical sounds of a motor running, you're most likely talking about an issue with the motor itself.
An issue with your blower may also cause a lack of airflow. It may have blown a fuse, have a defective connection, or simply suffer from normal wear and tear. Besides having weak or no airflow, another common symptom that may indicate a blower malfunction is hearing strange noises when turning your air conditioning on.
The best fix for return-air problems is to install a return-air grille from each conditioned room in your home back to the furnace, A/C or heat pump. Air coming into the room is balanced with the amount returning, regardless of whether room doors are closed.
Lots of things can cause your blower to have trouble, especially if it gets too dirty. A fan clogged by dirt, a stuck wheel, broken motor, or a loose fan belt are all common problems that reduce the amount of airflow you feel coming from your vents. How to fix: Call an AC tech to examine and fix the blower.
Check Insulation, Windows and Doors
If one room is staying hot while the rest of your house cools down, it might be that a window or door in that room isn't airtight. Make sure all the windows are fully shut, then check the sills for a crack or opening that's letting air through.
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.