A 20 minute session in a tanning be is equivalent to how many hours in the natural sun?
It is difficult to make a simple comparison between the sun and modern indoor tanning equipment. Just as various kinds of indoor tanning lamps and equipment differ in spectral output and energy emitted, the sun’s strength id dependant on several factors as well, such as the time of day or year, the latitude, cloud cover, pollution and reflection. Consequently, there is no formula for relating indoor tanning exposure times to outdoor exposure times.