That's not perhaps the best way to measure the power of the tanning unit, but most tanning units use lamps that are 100, 140 or 160 watts in power. Now, a more powerful lamp is going to require a lower exposure time. If you have a lamp that is twice as powerful as another lamp, the exposure time in a tanning unit for that more powerful lamp is going to be half of what the exposure time of that other lamp. So the exposure time multiplied by the intensity of the lamp equals the total amount of energy that is delivered. Just comparing the wattage of the lamps is not necessarily giving you all other story because if it is stronger, the exposure time is going to be shorter and it's all geared mathematically to deliver a dosage of light that is still non-burning regardless of the wattage of the lamp. Intensity times duration equals total amount of energy and we regulate the total amount of energy. So we keep it at a non-burning level based on your skin type and that is what is so valuable about a professional tanning experience.
