Natural Light Tubular Skylights Dark warehouses and commercial office buildings are no match for Natural Light's 21" commercial tubular skylights. Installed on virtually any type of roof surface in under two hours, our 21" commercial units are capable of delivering up to 1400 watts of light without the heat gain or loss of standard framed-in skylights. The 21" kit includes everything needed to install the skylight including 2 sections of 24" Light Pipe.