How to increase return air flow?

Author: Nolan Donnelly  |  Last update: Sunday, June 1, 2025

Use these techniques to improve the airflow throughout your second or third floor and enjoy your home year-round.
  1. Turn the Fan on to Increase Air Flow. ...
  2. Increase the Size of the Second-Floor Return Duct and Vent to Remove Hot Air. ...
  3. Put Smaller Return Vents and Ducts in Each Room.

What are the symptoms of not enough return air?

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.

How to increase vent air flow?

If you want to increase airflow in a room without affecting other rooms, here are our top recommended solutions.
  1. Open the windows and doors to the room. ...
  2. Enlarge the return vents. ...
  3. Ensure you clean the HVAC air cleaners. ...
  4. Close the vents to some rooms. ...
  5. Use a fan. ...
  6. Unblock the vents.

How can I improve my cold air return?

Down Low: if you have your air return lower on your wall it will function better as a cold air return. This will allow your air return to draw in cold air as it sinks to the bottom of the room. Making it more efficient at recirculating this cold air through your furnace to repeat the heating cycle.

Does adding a return increase airflow?

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.

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What happens if HVAC return is too small?

If the return duct is too small or there are an inadequate number of return grilles, your HVAC system won't be able to return enough air to recirculate into the system. Again, it's like if you were breathing in through a straw while jogging.

Why is my furnace not getting enough return air?

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. An improperly sized return duct is one of the most common reasons for this (another being an AC or furnace issue).

How to force more AC upstairs?

7 Ways to Make the AC Colder Upstairs
  1. Clean the air filter in your AC. ...
  2. Install a window air conditioner upstairs. ...
  3. Replace the AC system. ...
  4. Use your air supply registers efficiently. ...
  5. Seal the windows and open the doors upstairs. ...
  6. Close the curtains and turn off the lights upstairs. ...
  7. Insulate your attic.

Do duct booster fans work?

A duct booster fan improves airflow in HVAC systems by pushing air through ducts, ensuring every room receives proper heating or cooling. It's akin to giving a gentle push-to-air movement. However, their effectiveness depends on proper installation and addressing any existing HVAC system issues.

Should cold air return be on the floor or ceiling?

If you prioritize heating, put the HVAC and vents in (or below) the floor. This principle works for return heating vents as well. Place returns for cooling in the ceiling where the warm air congregates and heating returns in or near the floor where the cold air congregates.

How do you fix a weak air flow?

To resolve weak airflow issues, it is recommended to: check and replace air filters regularly. clear any obstructions near vents or registers. inspect and maintain the blower motor.

Why is my bedroom hotter than the rest of the house?

Common issues like leaks, disconnections, or obstructions within the ducts disrupt the flow of cooled air, causing rooms farther from the HVAC unit to suffer the most. In some cases, inadequate insulation of ducts can allow heat to infiltrate, further exacerbating the problem.

Does flex duct reduce airflow?

Additionally, due to its increased surface area, flex duct may impede airflow somewhat when compared with more streamlined rigid ducts. In some cases, an insulated flexible line may also be necessary if sound dampening or temperature stabilization are desired properties of a ventilation system.

How to fix air return?

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.

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.

Can you have too many return ducts?

Can You Have Too Much Return Air? Too much return air coming through your system isn't much of an issue because the fans and ductwork working to get that air back into the system only pull with so much force to make the HVAC system work correctly.

How do I increase airflow in my ductwork?

Ways to Increase Air Duct Flow
  1. Clean the Air Ducts. ...
  2. Add Ductwork Extensions or Registers. ...
  3. Install Automatic Dampers on Your Vents. ...
  4. Replace Furnace Filters. ...
  5. Install a Whole House Fan. ...
  6. Add More Insulation to Your Walls. ...
  7. Seal Up Drafty Windows and Doors. ...
  8. Install a Programmable Thermostat.

Where is the best place to put a duct booster fan?

For maximum performance and minimum noise, the best location to install your In-Line Duct Fan™ is 6 - 10 feet from the register you wish to boost air to. To prevent air leaks use a good quality duct tape to seal seams in the ductwork after installing the In-Line Duct Fan™.

Does reducing duct size increase CFM?

When it moves from a smaller to a larger duct, the velocity decreases. In both cases, the flow rate — the amount of air moving through the duct, in cubic feet per minute — stays the same.

Why is my upstairs so hot even with AC?

Insulation plays a crucial role in maintaining a consistent temperature throughout your home. If your upstairs is warmer, the insulation there may not be as effective as it should be. Lastly, your HVAC system might not be distributing air evenly throughout your home, resulting in hot spots.

How to set thermostat for 2 story house in summer?

Ideal Thermostat Setting for Two-Story Houses

In the summer, set the top floor temperature to the actual setting you want and set the bottom floor two degrees lower. For example, if you set the AC to 68 degrees F upstairs, set the downstairs thermostat to 66 degrees F.

How to circulate air from upstairs to downstairs?

So here is my list of options.
  1. Using a ceiling fan to push the hot air down from the upper story. ...
  2. Installing ducting from the downstairs system to the upstairs. ...
  3. Install a second ducted system upstairs. ...
  4. Install a ductless mini-split system in the upstairs. ...
  5. Install Ptac unit upstairs.

Why is there barely any heat coming out of vents?

While furnaces can stop operating for complicated reasons, home owners should check a few usual suspects first behind a lack of hot blowing air: Electrical problems causing a loss of power. Blocked air vents and ducts restricting airflow. Improperly configured thermostat settings.

How do you know if you don't have enough return air?

Low airflow can make your ears hurt in one room compared to another. Use a barometer to measure the pressure in the kitchen, living room, bedroom, and other rooms in the house. If you notice different pressure measurements throughout the house, this is a sign there's not enough return air.

Should HVAC returns have filters?

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.

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