Why Are There Little Handles On My Air Ducts?

Small Handles on Metal Air Duct
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If you are looking at your ventilation ducts, you may see small handles on the ducts. Maybe you are thinking what are those handles on my air duct for? Those handles are connected to dampers inside your duct work. Dampers can be rectangular or round and are designed to control airflow through your system. The dampers can either allow or restrict airflow to different areas or zones of your home. That is why they are often called zones dampers.

How Do I Know If A Damper Is Open Or Closed?

When dampers are installed correctly, the damper is open when the arm of the damper handles points down the length of the duct. The damper is closed when the handle points across or perpendicular to the length of the duct. If the ducts are unmarked, now is a good time to mark the ducts with a Sharpie pen to indicate what room the supply duct goes to.

In many areas of the country, homeowners will adjust the damper depending on the season. You may see a markings on the ducts that have a “W” for winter and and “S” for summer. If you see and “O” that is for open and “C” is for closed. When I was in Michigan, the “W” was set to the full open position and the “S” was set at a 45 degree angle which would cut the airflow by 50% in the summer.

You can use dampers to close off heat or air conditioning to one area of the house while forcing more airflow to another section that is used more often. If you have one room that is always too cold or too hot, check the damper to see if it is closed.  If the damper is open and you are not getting any airflow, the duct may be obstructed or disconnected.

A ventilation maintenance technician (VMT) or license HVAC technician with a bore-scope should be able to find if there is an obstruction or a disconnect. One of my realtor friends (Steven Colucci with RE/MAX Properties) had a bedroom in his newly-built home that was always cold. When he had his air ducts cleaned, the technician found a pair of overalls rolled up and stuffed in the supply duct to that room. He also found several small sections of wood had been dropped into the duct during construction. Once the overalls and the construction debris was removed, the room stayed warm like the rest of the home.

Some homes do not have dampers and some have motorized dampers that will open or close based on the operation of the furnace or A/C. If you have or want motorized dampers you should work with a licensed HVAC professional to set up the operation of your dampers to best meet your needs. There are many YouTube videos that explain damper installation and use.

  1. Check the position of your dampers
  2. Mark your ducts with a Sharpie to indicate what room they go to.
  3. Change your furnace filter. Write the filter size on the access door.
  4. Have your air ducts cleaned by Planet Duct in Colorado Springs.

What Can You Do Now?

I hope this article explained well enough why there are little handles on your air ducts. If you have more questions, see our blog page or call Planet Duct at 719-728-5111

Planet Duct- Air Duct Cleaning