How to Adjust Baffles Inside Furnace Ducts

Kirk Maltbee

Using electricity or fossil fuel, furnaces faithfully provide heat to a home when outside temperatures become chilly. Furnaces aren’t without their fair share of maintenance issues, however. For instance, you may manually have to adjust the baffles in the duct work to promote a proper and desirable balance between cool and warm air so that each room receives equal heating. Luckily, this is a relatively simple do-it-yourself task.

Proper baffle adjustment ensures uniform heat throughout a home.

Step 1

Locate the baffle handle on the outside of the furnace that controls the system’s internal valves. If you don’t know where they are, consult the owner’s manual included with your furnace or download a printable version from the manufacturer’s website if applicable. Generally, the baffle handles are close to the main housing unit of the furnace.

Step 2

Make note of the baffle’s current setting: if you’re coming out of a warm season into a cooler one, mark a small notch with a marker next to the handle to show its location. This will make it easier to find the appropriate and comfortable setting when the weather starts to warm and you desire to keep the home cooler.

Step 3

Find the dampers – the small circular flaps that swing somewhat loosely on a small hinge nut on the furnace’s piping. Inside the hinge is a small screw pin; manually adjust the screw by screwing toward you, which tightens the pin, or away, which loosens. Make the necessary adjustments so that the damper rests parallel to the floor, meaning the damper is open.

Step 4

Adjust the damper over the course of a few days and note the temperature changes in the home and your personal comfort level. You want to find the right medium, the right balance between the two, and when you do, mark the direction of the damper with a marker. To indicate the difference between summer and winter settings, mark an "S" or a "W" at the indicators to make future adjustments easier to find.