Depending on the type of system you have, your indoor unit (or air handler) will either be a fan coil or a gas furnace. Your air handler plays an important role in keeping you comfortable all year long. In the summer, it can help keep humidity levels comfortable and can increase your system's cooling efficiency. In the winter, it delivers warmth throughout your home.

Variable Speed
Variable speed air handlers, which are more efficient than standard air handlers, can increase your system's SEER rating by up to 2 full points. Variable speed units provide superior quiet comfort with heavy-duty cabinet insulation and slower air-flow through the duct work. A gradual, quieter start-up means that you will notice less starting and stopping of your equipment. You can choose continuous fan operation to provide greater energy savings and maintain more even temperatures throughout the home while enhancing indoor air quality. When combined with the Thermidistat™ Control or ComfortZone II, variable speed air handlers can remove up to 30 times more moisture from the air than standard systems.

See how furnace work.