The best replacement for air handler is furnace.

The best alternatives to air handler are rated as following:
★★★★★  furnace
★★★★  air conditioner
★★★★  gas furnace
★★  electric furnace
★  fan coil
  single speed
  evaporator coil
  ac unit

Your alternative for air handler is not listed? Suggest!
Speaking about air handler, one probably shouldn't forget about heat pump.

Other search terms related to air handler and their ratings are:
★★★★★ heat pump
★★★★★ heating coil
You have in mind a companion for air handler and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of air handler in all years. Click on graph for more.
air handler
furnace
air conditioner