Indirect Gas-Fired Heating

Greenheck's indirect gas-fired heating make-up air units feature 80% total efficient furnaces. All Greenheck furnaces use a swaged, 4 pass, tubular heat exchanger design and are power vented. This is done to maximize the unit's furnace life by preventing expansion/contraction issues and condensing within the heat exchanger. Single, duel, and triple furnaces can be configured in series and are available with up to 16:1 modulation per furnace. With a 3 furnace system, this offers 48:1 seamless modulation!

Indirect Gas-Fired Heating


  • Model IGX

    Model IGX

    Model IGX is a highly configurable indirect gas-fired heating system that incorporates a modular design for maximum flexibility. In addition to constant volume 100% outdoor air operation, recirculation and variable air volume options are also available. The IGX also has expanded heating, cooling, and airflow capacities to provide make-up air across a broad range of applications.

    • 800 to 15,000 cfm and 3 in. wg
    • Up to 1,200,000 BTU/hr.
    • Cooling options: packaged direct expansion, split direct expansion, chilled water, or evaporative cooling
    • 16:1 electronic modulation per furnace
    • ETL listed

  • Model IG

    Model IG

    Model IG sets the standard for an efficient approach to tempered make-up air applications. In addition to constant volume 100% outdoor air operation, variable air volume options are also available. Model IG can be configured with multiple intake and filtering options while also allowing for optional evaporative cooling.

    • 800 to 7,000 cfm and 2 in. wg
    • Up to 400,000 BTU/hr.
    • 4:1 electronic modulation
    • ETL listed


Other Info

Application Information

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