Not enough airflow:

If there doesn't seem to be enough airflow or it is less than it used to be, there are some things to check before calling for service.

Keep in mind that many of today's high efficiency and electrostatic air filters do restrict more air. They must really be kept clean or they can cause airflow problems.

Below is a list of possible causes and things to check. Items in blue usually require a service call.


  • Faulty indoor blower motor
  • Loose, worn fan belt
  • Incorrect pulley sizes
  • Indoor coil frozen due to malfunction, restricting airflow
  • Fan speed set too low, possibly boosting to higher speed
  • Blower wheel and/or coil could be dirty
  • Ductwork not properly sized or installed
  • Debris, obstruction, or closed damper in ductwork
Dirty filter - the cleaner the filter the better the air-flow
Make sure vents are open, including return vents
Make sure dampers are opened - handle should be in-line with duct. Turning handle 90 degrees closes damper