How to Adjust the Airflow in a House

The comfort level of your home often depends on the airflow.

Adjusting the Ducts

Keep the area around the furnace clean to increase its efficiency.Keep the area around the furnace clean to increase its efficiency.
Whether you're adjusting your heating ducts, vents or opening a window, each change affects the airflow throughout the house. An efficient airflow through your house also affects your heating and cooling bills. By adjusting the airflow to the rooms that need additional warm or cool air, you may significantly reduce your annual energy costs.

Step 1

Locate the ducts leading from the main heating and cooling ducts in your attic, crawlspace or basement. Use a flashlight to examine the ducts for small levers.

Step 2

Look closely at the lever to determine if it's parallel or perpendicular to the ductwork. Parallel means the damper is open; perpendicular means the damper is closed and there's little or no airflow through that duct.

Step 3

Adjust the lever to reduce or increase the airflow in the duct. Change only one duct at a time to determine how it affects the rest of your heating and air conditioning system.

Step 4

Mark the settings of the levers when you've adjusted the airflow to your satisfaction, using a permanent marker. Next year you'll be able to switch from winter to summer settings and back again without waiting several days between each adjustment.

Adjust the Registers

Step 1

Locate the register in each room where the airflow needs adjustment. Depending on your home's heating and cooling system, the registers may be on the floor, wall or ceiling.

Step 2

Adjust the register by using the lever. Some older registers may not have a lever, requiring that you pull the register out of the floor or wall to manually open or close the vent.

Step 3

Wait a day or two between adjusting the registers in the next room as each time you open or close a register, it changes the dynamics of the airflow.

Manually Add Airflow

Step 1

Add a fan to rooms that seem stuffy or lacking in air circulation. A floor, table or ceiling fan moves the air around without significantly increasing your power bill.

Step 2

Open a window on warm days in the winter or at night during the summer to allow fresh air into your home. On hot days, open an upstairs window on the downwind side of the house to vent hot air from your home.

Step 3

Use the bathroom and kitchen fans to remove hot, moist air from the house when you're showering or cooking. Venting the moisture out and increasing the airflow helps prevent mildew and mold from growing in these rooms.

Things You Will Need

  • Flashlight
  • Permanent marker
  • Electric fan
  • Ceiling fans (optional)


  • Avoid closing more than 25 percent of the registers in your home. Closing too many registers puts a strain on the heating and air conditioning systems.
  • Seal leaky ductwork with butyl tape or foil tape, which is made for use with hot-air ducts. Don't use duct tape; it won't hold up.
  • Change the furnace filters monthly to increase airflow through the entire system.


  • Use caution when climbing on ladders or moving around in the attic. You can fall through the ceiling if you lose your balance.
  • Wear gloves, long pants and long-sleeves, safety glasses and a dust mask if you have to crawl through a dusty attic or under the house. Protect your skin, eyes and lungs from dust, spiders and possibly rodent droppings.

About the Author

With degrees in fine and commercial art and Spanish, Ruth de Jauregui is an old-school graphic artist, book designer and published author. De Jauregui also worked in the Napa Valley as a high-end catering assistant. She enthusiastically pursues creative and community interests, including gardening, home improvement, pet rescue and social issues.