LF25 Unit Heater

Lennox Commercial Heating 1


  • Designed for exceptional performance
  • Two-stage LF25 now available in 250-400 kBtuh
  • Up to 83.8% thermal efficiency
  • 25% less pure tones and projections than leading competitors
  • Easy to install with compact units offering 180-degree installation capabilities
  • Hinged access doors
  • Dimpled tubular heat exchanger design
  • Additional advanced features include DSI board with 11 diagnostic codes and LED FDD capabilities
  • Residential heating capacities from 30,000 to 105,000 BTU/h
  • Commercial heating capacities from 30,000 to 400,000 BTU/h
  • Vertical units available with either aluminized or stainless steel heat exchangers


  • 180-degree installation position capability on compact models
  • Cage-nuts for all-thread installation on vertical units
  • Conveniently located gas connections
  • Removable terminal block for line voltage and thermostats
  • Hinged door allows easy access to all components
  • DSI control board has 11 diagnostic codes and remote LED fault detection diagnostics enabled
  • Each unit is factory wired and tested with complete cycles of startup and shutdown before being shipped