Abstract: The present invention provides a ventilation system for a perishable goods store and a method of operating a ventilation system for a perishable goods store. The system of the present invention may monitor and control the temperature and humidity of the goods within the store and comprises a controller for automatically operating the system, a duct through which air is propelled into the store, pressure control means for controlling the pressure within the duct and a pressure monitoring means for measuring the pressure within the duct. The controller monitors the pressure within the duct and controls the pressure control means ensure the air pressure within the duct is maintained within a defined pressure range. The pressure control means may comprise at least one variable speed fan. The present invention is advantageous in that it optimises the back-pressure within the duct, against which the at least fan must act, thereby providing a more efficient ventilation system.