Lennox Gas GCWB95 Boiler

Lennox Gas Fired GCWB95 Boiler

High-efficiency, gas-fired water boiler

The GCWB95 Gas Fired boiler offers an AFUE rating of 95%, which means it converts a full 95% of your fuel into usable heat. It has earned the 2020 ENERGY-STAR® Most Efficient award. And it delivers warmth quickly with a cast-aluminum heat exchanger that transfers heat three times faster than conventional cast iron.


  • Efficiency rating of 95% AFUE.
  • ENERGY STAR® qualified which means it meets or exceeds U.S. federal guidelines for energy efficiency.
  • Stainless Steel heat exchanger transfers heat up to three times faster than traditional cast-iron exchangers.
  • Easy integration with traditional radiator systems to provide precise heating comfort, regardless of outdoor temperatures.

Energy Efficiency

  • Stainless Steel heat exchanger—transfers heat up to three times faster than traditional cast iron exchangers
  • ENERGY STAR® qualified—meets or exceeds EPA guidelines for energy efficiency, which means energy savings
  • Electronic ignition control—monitors water temperature and maximizes efficiency by turning on the burner only when needed

Home Comfort

  • Faster heating times deliver both home heating and hot water on demand
  • Sealed combustion—minimizes fan noise and provides quiet, soothing heat
  • Easy integration—low temperature supply and return water makes the unit compatible with existing radiant and underfloor systems

Reliable Performance

  • Self commissioning allows this combination bioler to make its own adjustments during installation for immediate comfort
  • Durable cabinet—heavy-gauge steel cabinet and baked-on paint finish
  • Compact and versatile—allows easy installation in a basement, closet or alcove enclosure, and can be fuelled by natural or LP* gas

*Shipped as natural gas; 050 and 075 models are convertible to LP.


  • 15-Year Limited Warranty on Heat Exchanger.
  • 10-Year Limited Warranty on covered components.
  • Certifications