1500 hours of UV refers to the number of hours WeatherMAX is tested in an accelerated Weathering System exposed to all spectrum UV, in addition to water, and changes in temperature and humidity. 300 hours of exposure in one of these machines is the industry standard or equivalent of one year outdoors. WeatherMAX 80 comes with a limited warranty of 10 years. WeatherMAX LT comes with a limited warranty of 3 years.