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Window restrictors are devices that stop windows being opened more than 100mm. They are important to maintain the security and safety of homes.

For rooms that are liable to solar gain overheating the option of opening the window to enable purge ventilation is very limited when restrictors are used.

Removing the restrictors can pose risks for occupants, while large glazed areas with large windows often increase the risk of overheating. Large windows are very difficult to give opening and safety characteristics that will mitigate against overheating risks.

Our experience is that careful consideration needs to be given to both the window and façade design that will allow safe opening without restrictors to give purge ventilation.

This requires the façade architects to work closely with our specialists carrying out the overheating analysis to ensure that the façade design is efficient in maintaining a high quality internal environment.