Heat and Lighting
Providing the right type of heat to a reptile is just as important as the temperatures you provide. Reptile vets, biologists and an increasing number of experienced herpetoculturists are all saying that that best source of heat is through an overhead radiant source, not by a hot rock or heat tape. So, when confronted with a shelf full of pretty boxes of light bulbs produced to attract your attention, how do you know which one to select for your reptile? Here are a few things to keep in mind...
Reptile Basking Lights
Spotlights / Silvered Reflector Lights
Infrared Heat Lamps
Lights for Nighttime Use
Non-light Emitting Heat Sources:
Ceramic Heating Elements
People Heating Pads
Reptile Heating Pads
Flex-watt Heat Tape
Any incandescent white light can be used for daytime lighting and heating. Nocturnal reptile lights and dark decorative red, blue and green incandescents provide dim lighting that will not disturb the sleep of diurnal (active during the day) reptiles and isn't stressful to nocturnal reptiles. Diurnal reptiles need a bright white light during the day if the ambient room lighting is dim or the only other source of light is a UVB producing fluorescent.
Incandescent Lamp/Ceiling Fixture Bulbs
Reptile Basking Lights/Spots
UVB (Ultraviolet B) and UVA (Ultraviolet A)
The only lights that can safely provide these two critical wavelengths to your diurnal reptiles are the UVB/A producing fluorescents made for the reptile pet trade. (Note: for the problems associated with the use of screw-in compact fluorescents, please see my comments in the UV Table article referenced below.)
Fish/Aquarium and plant "grow" lights-incandescent and fluorescent-do not produce UVB. Tanning salon fluorescents, tubes made for phototherapy for humans, germicidal UV tubes, and mercury vapor lights, all of which produce UV, do so at levels that are unsafe for the reptiles and their keepers. Many of these produce very high levels of UV and are designed to be used for very limited periods of time and require that protective eye gear be worn (and to my knowledge, despite the availability of ponchos, sombreros, and motorcycle jackets, no one has made UV resistant goggles for iguanas yet....).
Some of these lights also produce UVC, that range of wavelengths (< 290 nm) known to cause immune suppression and cancer in humans and animals. UVB producing fluorescents that produce a decent amount of UVB (1-5%) aren't very bright (have lower CRI) - bright UVB producing fluorescents (high CRI) do not produce much UV; that is a tradeoff required by the technology itself.
CRI - Color Rendering Index
Importance of UVA
Some Points to Remember When Setting Up Your Enclosure
Placing the Lights
Replace UVB Fluorescents Regularly
Watch the Distance Between your iguana and the Light