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Innovation Watch - Helping Buildings Breathe

Monkseaton High School was completed in 2009 and is ventilated with the help of e-stack units situated in the roof

A Cambridge-based company, Breathing Buildings, has achieved rapid commercial success by producing natural ventilation systems that actively manage CO₂ levels and cut energy bills. By optimising the use of external fresh air and heat generated by, among other things, people and equipment, buildings are being kept ventilated with the minimum use of mechanical aids.

One of The Royal Academy of Engineering’s Silver Medal winners this year is Dr Shaun Fitzgerald, co-founder of Breathing Buildings, a company that in 2006 was spun out of a major research programme at the University of Cambridge.

The company’s patented ‘e-stack’ natural ventilation systems are used in a variety of buildings, including more than 40 schools and colleges. Some of these incorporate noise attenuation devices which helps deliver the dual benefits of fresh air and a quieter environment.

Energy-efficient e-stack systems employ a combination of natural ventilation methods to keep buildings circulating fresh air throughout the year. There is upward displacement ventilation in the summer and natural mixing ventilation in the winter – when the incoming cold air is mixed with the warm internal air before it reaches the occupants. This ensures that the building remains comfortable and avoids the risk of cold draughts often associated with natural ventilation systems. This combination also means that less energy is needed than for conventional natural ventilation systems, as pre-heating is not required.

Passive night cooling uses the thermal mass of a building to further increase system efficiency, with low-energy fans enhancing the flow of air where appropriate. E-stack utilises an algorithm that automatically activates the system based on temperatures and CO₂ levels.

As each project generates potentially different challenges, Breathing Buildings offers a design consultancy to customise the company’s overall system installations. This enables them to work within a building’s architectural restraints and avoids the possibility of temperature stratification that can lead to undesirable cold or hot zones.

E-stack technology has already been incorporated into numerous high-profile buildings. New products are in development and these will push the boundaries of energy consumption even further. More information is available at

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