The hottest part of the tubes gets maybe 2C or 3C above ambient room temperature. It is barely warm to the touch. Many of the consumer electronics you buy get much hotter, and have fans/heat sinks. This Thing doesn't need any type of cooling. You can buy plastic cases for this kit from the manufacturer, the PLA print works fine with no distortion at all. Actually, leaving the print on the dash of your car on a sunny day is far worse than the heat from the Nixie tubes.