Many air conditioners and heaters come equipped with ultraviolet lights. These UV lights convert irritating stuff like pathogens, pollens and mold spores into harmless toast. (Yes, that’s a metaphor.) They’re kind of like built-in filters because organic compounds break down when they’re flashed with a high-intensity UV light.

These UV lights can also break down, though. If your cooling and heating appliances are equipped with UV lights, Al’s can help restore burnt-out UV lights or a catalyst mechanism that’s not working properly.