The Breezway head office in the Brisbane suburb of Coorparoo employs natural ventilation to keep the building interior comfortable as well as energy bills low.

On a typical winter’s day in Brisbane with temperature at 23°C and a breeze blowing from the west, the environment inside the building across all three floors is comfortable though the air conditioning is switched off and the office windows are open. Altair Powerlouvre windows maximise the ventilation through each window. 

The ‘mixed mode’ cooling system in the building consists of a weather station on the roof of the building, which feeds into a building management system that decides how many of the windows should be open and whether or not the air conditioning should be running at any given moment. The building management system electronically opens and closes the powered Altair louvre windows and turns the air conditioning systems on and off.

While the day starts with the air conditioning system running to warm the building, the building gets warmed up quickly by mid-morning once most people have arrived and turned on their computers. Bodies and computers both generate heat, leading the building management system to determine that the building occupants and equipment are generating sufficient heat to turn off the air conditioning and open some of the windows to provide fresh air. 

The windows will most likely close late in the afternoon as the sun gets lower in the sky and the temperatures start to drop, at which point the air conditioning will be turned on again to heat the building.

It has been observed that the air conditioners have been turned off for around 40% of the time that the building was occupied through spring, autumn and winter, helping Breezway save a small fortune on their electricity bill.