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The Airextube Air Make-Up System can be used in all applications where the replacement of exhausted air is required due to general ventilation or local extraction. Without this air replacement the building is maintained under negative pressure, reducing the efficiency of exhaust fan and increasing infiltrations and drafts which make the work areas uncomfortable.


The Airextube is available in four different configurations allowing a wide variety of uses. This versatility permits the Airextube make-up air system to cover every need of the industry.

Single Compensation System (SC)

This unit has one motorized back-draught damper at the rear of the casing (damper X) that closes automatically when the unit stops operating to avoid any air infiltration. The fan and damper are operated by an on-off remote control if needed. This control can be easily interlocked with the evacuation fan controls.

Compensation and Mixing System (CM)

The CM unit is similar to the CS, except for a mixing damper (damper Y) on top of the casing. This second damper, controlled by a thermostat placed in the ducting, pre-mixes the air in the housing during cold weather. As in the CS model, the unit is supplied with an "on-off" switch.

Recirculating system (RS)

This model has a different function than the two others. It is used where air compensation is not required (ex. warehouses), but where the cost of heating can be lowered by using the stratification in top part of the building. The unit is provided with an opening (Z) at the bottom part of the housing. A recirculating duct must be used to bring the air from the floor level to the "Airextube". The unit is supplied with a "on-off" switch.

Combined System (CR)

This model is provided with a damper (X) at the back and a damper (z) at the bottom of the casing. The unit has two functions : during the day, when the exhaust fans are working, it will act as an air compensation unit (CS); during the night and week ends, it functions as an air recirculation unit (RS). The unit is supplied with a three position remote control (compensation - off-recirculation).

  • High stratification temperature
  • Height of the building
  • Existing building under negative pressure


The operation of the Airextube is very simple and consists in using the hot air stratified at the top of the building to preheat the cold air introduced before it reaches the work area. The result is a uniform temperature from the top to the bottom of the building. Because the top layer of warm air is usually not utilized, the make-up air can then be considered as "free air". This represents an important advantage over the conventional gas or electric make-up units; the initial cost of an Airextube as well as its operation cost are much lower.


  • Weather hood
  • Motorized damper
  • Acoustically insulated Housing
  • Tubeaxial Supply fan
  • High velocity air jets
  • Polyethylene flexible duct
  • Drain pan
  • Fresh air intake duct with thermal insulation
  • Belimo modulating motors
  • Recirculating damper
  • Fresh air damper
  • Fresh air hood (Wall or roof type available)
  • Access door mixing box
  • Modulating temperature control (Duct)
  • Modulating temperature control (Room)
  • Freeze Protection
  • Metal mesh air intake filters
  • CSA approved control panel
  • Recirculating duct
  • Heat recovery coil
  • Electric heating coil
  • Cooling coil
  • High efficiency filter section