An accelerated weathering device, system and method is provided for rapidly weather testing insulating glass units (IGUs). The accelerated weathering system can include an air sealed vessel that can removably house an IGU, an air flow system in fluid communication with a chamber in the vessel, the air flow system operable to increase or decrease a pressure in the chamber, an exchanger system in communication with the chamber and operable to increase or decrease one or both of a temperature and a humidity level of the chamber, one or more UV bulbs, and a computer system operable to control the air flow system and exchanger system to vary one or more of the following parameters in the chamber: temperature, relative humidity, and pressure.