After the LEDs are on for 15 minutes, the output (PPFD) drops. This is due to the heating of the LEDs. For LED lamp A, the output drops from 98 to 97 micromol. For LED lamp B, the output of the LEDs drops from 94 to 89 micromol. It is important to look at how the LEDs are cooled to minimize this degradation. From the graphs, we conclude that the cooling technique of lamp A was more effectively applied.