Roof Ventilator Comparison

This comparison is based in performance between a well engineered

rotary type steel roof ventilator (Western Rotary) and the passive multi venturi Condor Kinetic type.


……………………………………………………………………………………………………….Condor Windtower Roof Ventilator

   Condor Kinetic Windtower Roof Ventilator


Roof Ventilators – A Comparison Study of Rotary/Turbine to Condor Kinetic

Rotary/Turbine Type
Commercially developed in the United States in early 1900s to remove welding fumes in factories during the winter months. This is a predominantly winter ventilator.

Mode of Operation
Wind Driven

Rotary/turbine ventilator uses wind energy as it’s governing mode of operation.

Initial Conclusion

Rotary/turbine can best be referred as a Winter/Wind ventilator as it’s efficiency is governed by wind speed which is predominant in the Autumn, Winter and Spring months, particularly at the change of seasons.
Highest efficiency according to wind velocity.

Rotary type will move a fixed volume of air (irrespective of temperature or season) dictated by wind velocity.

No wind, no function

Where no free air (replacement volume) is available

Rotary/turbine type is dictated by availability of a replacement volume (free air).
Rotary/turbine type cannot displace what cannot be replaced.

Performance during cooler months

Rotary/turbine unit is suited to this period, however is deemed detrimental in residential applications as dry warmer air in roof is removed and replaced with ambient which has greater moisture levels.

Performance during warmer months

Rotary/ turbine type is not suited to this periodWhen no wind movement is available, the only way hot air can escape is by having to overcome the resistance created by the turbine rotor. It is therefore less efficient than a simple open unobstructed hole in the roof.

Multiple units are required for roof void (attic) areas above above 80 sq/m.

Re – Maintenance

Rotary/turbine type, requires periodical maintenance or replacement.

Is inclined to be noisy prior to requiring replacement.


There are no similarities between the two types as can be clearly observed.
The principles governing the mode of operation between the two products are almost totally opposite to each other.
Their selection as to purpose and use is dependent entirely on the task they are expected to perform.

Condor Kinetic Type
Initial product patent in Australia in late 1980s for removal of heat from buildings. This is a heat and pressure driven roof ventilator designed for summer conditions.

Mode of Operation
Heat & Pressure

Motionless Condor Kinetic type is designed to use air pressure and heat load as it’s governing mode of operation with wind as a secondary contributor.

Initial Conclusion

Motionless Condor type can best be referred as a Summer/heat ventilator as it’s efficiency is governed by internal and external heat and pressure.
Highest efficiency during summer months.

Motionless Condor Kinetic type will move a high volume during the Summer and low volume during Winter.
The Condor type is also unsurpassed in zero wind velocity

Where no free air (replacement volume) is available

Condor Kinetic type is able to offer air volume exchange as dictated by pressure fluctuations both internal and external of the building. Put simply the Condor type allows the building to breathe in and out.

Performance during cooler months

Condor Kinetic mode of operation is also suited to this season. It is ideal in residential / institutional situations to ensure the dry air is not removed from roof cavity and replaced with external moist ambient.

Performance during warmer months

Condor Kinetic type was designed for and performs well in this season. Distinct advantage in that only one correctly sized Condor is required for a
conventional residential roof, either tile or steel.

For residental dwellings, only one correctly sized unit is recommended for dwellings with common roof void (attic area only) not exceeding 300 sq/m

Re – Maintenance

Condor Kinetic Windtower is motionless/passive, requires no maintenance and is noise free.

Fire Risk Areas


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