It is easy to adjust the bulb(s) to a height that does not burn the plants whether you are using 1 or 2 bulbs. Light follows the inverse square law, as the distance increases form a point source, the light intensity is decreased by the square root of the distance. For example: if you move the light 2 x the distance the light in lumens will be decreased by the square root of 2 or 4x . If it were 3 x the distance the light would decreased by 9 x. So small adjustments are easy to make and have a significant effect. If the cabinet temps begin to get too high, simply vent the space by opening the door for a little bit.