Evaporative coolers work on the principle that they continuously replenish the air inside your house with outside air, cooling and filtering the air from outdoors as it passes through the appliance. Under normal conditions the outside air is ‘fresh’. However, the current devastating and unprecedented bushfires have resulted in periods of very poor outdoor air quality. With this in mind, Rinnai/Brivis recommend you do not operate your Evaporative cooler during periods of very poor air quality.