Housing chameleons is largely determined by species. There are factors which will differ in many species which have to be measured (preferably at time of purchase) carefully. Although enclosure sizes are fairly universal, the habitat contained within them can vary dramatically.
Before choosing your chameleons, be sure that you will be able to maintain the type of habitat that particular species requires. Aquariums are acceptable at first (if your chameleon is very young or a smaller species), but you should move to a larger, screened enclosure when your reptile gets a little older as they allow for better air circulation and temperature variance.
Make sure to include real plants, different sizes of climbing limbs, and proper lighting systems in whatever enclosure you are using.
Your enclosure should have a variance in temperatures so that the animal can either
warm up, or cool down depending on its current state. This can be easily accomplished
through strategic placement of lighting, and plants. (Make it a point to use real
plants instead of artificial ones since these will also help to maintain humidity,
and overall air quality).
Aquariums are acceptable at first (if your chameleon is very young or a smaller
species), but you should move to a larger, screened enclosure when your reptile
gets a little older as they allow for better air circulation and temperature variance.
Since chameleons will not normally drink from a dish, you will have to mist them
with a spray bottle regularly. Don't cut costs by trying to clean out an old Windex,
or hairspray bottle, (as this could prove fatal) buy a new one. If possible, you
should also include a water drip system. A simple version can be created by placing
a paper cup with a small hole in it on the roof of the enclosure. Try to set it
up so that the water cascades over the leaves of the plants in your enclosure.
This will most resemble the means by which your chameleon would attain water in
a natural environment. Alternately, you can purchase a commercial drip system.
They are inexpensive, and will provide your chameleon with an available water
supply for a relatively long period of time.
Make sure to purchase a good quality, full spectrum (UVA / UVB) light, since chameleons
require full spectrum light to produce vitamin D for proper absorption of calcium.
(Avoid buying a screw-in type of light which claims to be full spectrum, as theses
are usually very low in the UVB spectrum). If you try to save money by not buying
full spectrum lighting (unless you live in an environment which permits you to
keep your enclosure outdoors in direct sunlight), you are likely encounter problems
such as Metabolic Bone Disease (bone curvature in the limbs).
Buying a special basking light is not necessary, since a standard floodlight or spotlight can be used for temperature regulation. You should use a thermometer to make sure that the temperature ranges in your enclosure are within acceptable parameters for the species you are housing. Typically, the basking spot will be at one end of the enclosure so as to provide the maximum temperature variance from one end to the next.
To make things a little simpler, you may want to include artificial vines in you
enclosure. These are very flexible and strong, and are generally very realistic
looking. Companies such as Biovine, Fluker Farms, and Flexi-Vine each make their
versions of these which are usually available in different lengths, and diameters.
Including these in your reptarium in varying sizes will help to provide more space
for your pet to climb around on, thus improving your chameleon's strength, dexterity,
and overall well being. Make it a point however, to verify that the materials
used in creating the vines are nontoxic.