Heating and lighting for chameleons is very important for several reasons. Firstly, it raises the temperature of the chameleon which is essential for proper metabolism and digestion. Chameleons also require UVA and UVB rays to see and to help them produce or absorb essential vitamins such as vitamin D3. The best source of lighting is natural sunlight but many owners live in areas that do not permit this to happen. Canadian such as myself must use artificial lighting for most of the year.  

Generally you should have two lamps. A fluorescent lamp, and heat lamp (or reptile dome). The bulb used for the fluorescent fixture should be made solely for the purpose of reptiles and amphibians, and contain the appropriate intensity of the beneficial rays. A Repti-Glo 5.0 is sufficient for chameleons and can be purchased at most pet shops.

 

The bulb contained in the heat dome may be any type of bulb, providing it raises the temperature to the requirements of that species of chameleons and is clear or white in colour as opposed to blue red and other colours. 

 

When placing the lamps you should have them lit from above as the sun would do so naturally. The flourescent lighting can sit directly on the cage, however this is not the case with incandescent heat bulbs. The screen and or the chameleon itself could easily get too hot and burn. Burns may furthermore become infected, the best cure is prevention. Hang the lamp at least a few inches away from the cage or screen. If it is unbearably hot for you (test with your hand) on the screen, it is likely too hot for the chameleon and appropriate measures should be taken. Of course thermometers are a must to ensure proper temperature is kept within the basking area and the rest of the enclosure. Be sure to place multiple thermometers throughout the cage to ensure the proper temperatures are maintained such as under the heat lamp (hot area) and the cooler end of the cage. The heat lamp should be placed above an area where there are multiple levels of height, so the chameleon may heat itself at the preferred temperature. Thermometer guns are a very handy tool as well. It is a digital instrument where it is simply aimed at a certain area of the enclosure and with the press of the button an immediate accurate temperature reading is provided. 

Mercury vapour bulbs are handy if you would like only a single lamp. To my knowledge, they emit heat and UVA/UVB all in one. The rays seem to penetrate much further in the enclosure. The major down side is they are very costly.

*Note that UVA/UVB bulbs lose their effective rays after around 6 months or so, and therefore should be replaced that often, even if the bulb has not burnt out.*