Tanning bed bulbs should be changed when they reach approximately 80 percent of their recommended lifetime hours. Using this example, bulbs with a life of 1,000 hours should be changed when they reach anywhere from 600 to 800 hours.
In general, tanning bed lamps emit the strongest ultraviolet, or UV, rays in the first 50 hours of use, which causes the body to tan faster. Therefore, less time should be spent in beds with brand new bulbs. After 50 hours, the UV output decreases to approximately 20 percent power and remains at that rate until the bulbs have been used a total of about 500 hours. Once that number is reached, efficiency decreases dramatically down to 50 percent. At that point, it is time to consider replacing the bulbs.
When replacing bulbs on a tanning bed, they should all be replaced at one time. One should not simply replace a single bulb that has burnt out or lost power. Since bulbs are strongest when they are new, replacing one at a time will result in an uneven tan. To ensure all the bulbs are putting out the same UV strength, tanning bed owners can purchase a UV reader. This is a meter that reads the strength of the UV rays that are emitted from the lights.