It’s a beautiful winter’s day in Brisbane (Australia) today: blue skies, 23C with a breeze blowing from the west. Unlike most other office workers around the city today, I can actually feel the breeze. It’s not because I’m working outside though, it’s because the air conditioning is off and the office windows are open. No, I don’t work in a small home office, the Breezway head office here in the suburb of Coorparoo, Queensland has a floor area of 900m2 spread over 3 floors.
Unlike most other offices though, ours has windows that open (Altair Powerlouver Windows to maximize the ventilation possible through each window) and uses a ‘mixed mode’ cooling system. We have a weather station on the roof of the building which feeds into a building management system. This 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 Altair Powerlouver Windows and turns the air conditioning systems on and off.
Although it’s a beautiful day now, this morning was really cold. It got down to 42.8F overnight and was around 46.4FC when I arrived at 7am. The windows were all closed then and the air conditioning was running to warm the building. Around mid-morning, most people had arrived and turned on their computers. Bodies and computers both generate heat, so both were helping to warm the building and the building management system determined that the building occupants and equipment were generating sufficient heat to turn off the air conditioning and open some of the windows to provide fresh air. The windows have been open since then and will probably close late this 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.
So far, through spring, fall and winter the windows have been open and the air conditioners turned off for around 40% of the time that the building was occupied. It’s clear to see that with no air conditioners running through a significant portion of each work day, we’ve saved a small fortune on our electricity bill, all while enjoying the breeze as we work.
Winter in Brisbane can be glorious… I think I’ll take the family to the beach tomorrow!
If you’re interested in seeing and learning more about the Breezway Head Office, a short (9:28) video “Natural Ventilation in Offices – A Case Study by Breezway” is available on the Video Showcase page of our website.