The first place to look for potential energy savings is the furnace itself. We recommend that you call a heating professional for a complete annual checkup of your heating system to make sure it's in safe operating condition. Clean or Replace Furnace Filters Regularly Most furnace filters are disposable.
Some filters are washable and can be cleaned when clogged or dirty.
Checking the filters in your system once a month during times of high use will help insure proper airflow. Be sure to keep a couple of correctly sized filters on hand if yours are disposable. If you are installing a high efficiency filter, make sure that the airflow through the furnace can be maintained at the proper level.