Why isn't my range hood's fan pulling much air?

When the range hood fan isn't pulling much air, clogged air filters, air duct problems, a fan motor failure or a broken fan blade could be causing poor air suction.

If your range hood exhausts air to the outside of your home, check the condition of the grease filters. Wash or replace the grease filters if dirty. Next, check the air damper on the vent duct cap attached to the outside of your house. That air damper keeps outside air from flowing into your home when the range hood fan isn't running. Repair or replace the air damper if it doesn't open to allow range hood exhaust air to flow out of the exhaust duct. Also, check the damper above the fan in the range hood to make sure that damper opens properly to allow air to flow out through the exhaust duct system. Check the fan blade for damage because a damaged fan blade won't move air through the range hood properly. Replace the fan blade if damaged. A weak fan motor won't turn the fan blade at the right speed to move air through the range hood. If the fan motor makes noise or doesn't turn the fan blade at full speed when activated, replace the fan motor.

If your range hood recirculates the air back into the kitchen (non-ducted installation) and uses a charcoal recirculation filter, a clogged filter can diminish airflow through the range hood. Replace the charcoal filter if you haven't replaced it according to the guidelines in your owner's manual. Next, check the condition of the grease filters and wash or replace the grease filters if dirty. Check the damper above the fan to make sure it opens properly so exhaust air can pass through the damper and recirculation filter. Repair or replace the air damper if it's stuck closed. Check the fan blade for damage and replace the fan blade if damaged. If the fan motor makes noise or doesn't turn the fan blade at full speed when activated, replace the fan motor.