It is therefore important to direct the heat away immediately after it is generated in the fixture. Fosbit does its own testing and simulation to determine the heat management performance. In the integrated fixtures we supply, a metal heat sink connects the electronics to the outer surface, where heat can escape. In 'retrofit' lamps like LED tubes (LED-TL), this is not possible. Such lamps try to force LED into the form factor of a conventional lamp. As a consequence, heat accumulates inside and the lamp quickly deteriorates. Properly cooled LEDs last as long as the frame they are in, so the traditional distinction between 'lamp' and 'armature' is superfluous and in fact detrimental to lifetime.

Producers who use plastic PCBs (e.g. FR4) cannot guarantee a long lifetime. In addition, the PCBs must be firmly attached to the heat sink, preferably with thermal paste in between. In a good fixture, the LEDs cannot be replaced with a simple procedure: LEDs on unattached PCBs fail much earlier. Producers who advertise loose, replaceable PCBs will be unable to fulfill their durability promises. Scrutinize their credit ratings, because before long they will have to buy you new LEDs.

Higher current means more light emitted per LED, but also lower efficiency and shorter lifetime. Fosbit prefers to keep the current far below the specified standard current. It makes our investment somewhat higher, as we need more LEDs to reach the right illumination levels. We recover that as the LEDs live longer and use less energy in total.