I have 1 exo terra 150 13 watt and one exo terra 100 26 watt. The 100 is as low as they go. My tank is,steady at 85 degrees ambient temp so I don't have a heat light. They just sit on the vine that is 3 inches under the light if they want to bask.
Chameleons eyes are delicate, so it is possible to provide too much concentrated UV light.
85 is too hot for some species of chams.
Can you relocate the cage to a cooler area of the house, such as the basement?
You could then use a very low wattage basking bulb.
