Air handler units offer a versatile replacement for traditional air conditioning systems that can be connected to pre-existing duct work, but with smaller units that are quieter (variable speed fan motor) and more energy efficient. The air handlers, which are available in 18K, 24K, 36K, 48K, and 60K Btu/h models, can be installed vertically, horizontally, or downward. These units can be connected to any 24V wall thermostat and are compatible with standard 18K to 60K Btu/h outdoor models or Hyper Heat upgrades, which provide dependable heating in ambient temperatures as low as -22°. Models ranging from 36K to 60K Btu/h work for single zone applications, while 18K and 24K Btu/h are compatible with both single and multi-zone condensers. Notable features include high static pressure and Quiet Operation.