A bearded dragon's lighting set-up should mimic what the reptile would get in the wild as closely as possible. To achieve this, you should first know what a natural environment for a bearded dragon is.
What Kind of Lighting Does a Bearded Dragon Need?
Being from the desert, beardies in the wild receive high levels of UVB and heat from the sun on a daily basis. In order to best mimic this in an indoor enclosure, high UVB output light bulbs must be used in addition to heat bulbs.
What Produces UVB Rays?
Aside from sunlight (not filtered through a window), there are a couple of different sources of that give off invisible UVB rays. Fluorescent bulbs and mercury vapor bulbs are the two sources most commonly used in the pet world.
Special fluorescent bulbs that fit into fluorescent fixtures give off varying levels of UVA and UVB (usually given as percentages) rays. These full spectrum bulbs run out of rays before the lights actually burn out, therefore they need to be replaced per manufacturer recommendations, or every 6 months.
Bearded dragons need an 8-10% output of UVB rays which should be clearly marked on the bulb packaging. These bulbs are to be placed 6-8 inches from where your beardie can get to soak in the rays. Also make sure the bulb is not placed on a plastic, plexi-glass, or glass surface. These types of substances will block the rays from penetrating into where your reptile needs them.
Newer research also shows that the typical metal mesh screen commonly used for reptile tanks blocks a significant amount of UVB rays as well. Therefore, try to mount your bulb on the inside of the enclosure to make sure as many rays reach your beardie as possible.
Mercury vapor bulbs serve more than one purpose for your bearded dragon.
They emit both UVA and UVB rays and they also provide heat for your enclosure. This allows you to use only one bulb to provide both heat and the important UVA/UVB rays in place of the usual two.
These bulbs last a great deal longer than fluorescent bulbs and heat bulbs and although they cost more, seeing that they last longer usually makes them worthwhile. Some people even note better appetite, coloration, and energy in their beardies while using mercury vapor bulbs.
There is some discussion in the reptile community that mercury vapor bulbs can be dangerous to reptiles because of the intensity of the UV rays produced by these bulbs. Despite the worries, a number of reptile owners have never had a problem. If you do decide to go with a mercury vapor bulb, be sure to provide plenty of shade opportunities in the enclosure, use a ceramic socket for the bulb, and keep a distance of 12-24 inches between your reptile and the bulb for safety reasons. This bulb is best used for large spaces that allow you beardie to roam.
These bulbs do all the same things as the regular fluorescent bulbs but they fit in an incandescent fixture. They also use less energy than a fluorescent bulb and should last longer but some research shows the UV is much too high for reptiles and they don't last as long as they should.
I specifically said heat bulbs and not hot rocks or undertank heaters for bearded dragons for a reason. Hot rocks can cause thermal burns and undertank heaters make it difficult to regulate the temperature in the enclosure accurately. UVA rays are also delivered to your bearded dragon by using certain heat bulbs.
The bulbs needed to heat an enclosure all fit in the same type of fixture - an incandescent ceramic socket.
Ceramic Heat Bulbs
Ceramic heat bulbs provide no light to an enclosure but they do provide heat. Just like regular incandescent light bulbs, they come in different wattages. The wattage needed depends on the size of the enclosure and if any other heat bulbs are used. Unlike regular incandescent bulbs, they last for an extremely long period of time, making them more cost effective, but they do not deliver UVA rays.
Therefore, these are a heat assisted device to a bulb that emits UVA rays (full spectrum fluorescent or UVA ray emitting heat bulb). Make sure these bulbs are not placed on a surface that will melt.
As stated before, there are stipulations with using this bulb, but it provides both heat and is a full spectrum bulb.
These are your typical heat lights that emit light, UVA rays, and varying wattages of heat. Different bulb sizes and shapes are available, as well as colors of light (wavelengths). Daylight bulbs are regular white lights, nightlight bulbs are blue/purple lights (make sure the bulb isn't painted blue/purple glass, but in fact blue/purple glass), and nocturnal lights are red (don't use painted bulbs).
The wattage needed depends on the size of the enclosure and if any other heat bulbs are used. The size and shape only matters for fitting in your incandescent fixture.
The shapes of these bulbs usually has a purpose. Basking lights are shaped to direct heat into the area directly below the bulb as opposed to the entire tank and are usually shaded on the sides to assist in directing the light.
Halogen Heat Bulbs
These bulbs do all the same things as incandescent heat bulbs and even though they cost a bit more, they emit more heat, light, and UVA rays than an incandescent bulb of the same size. They also usually last longer and use less energy than incandescents.
Some halogen bulbs fit in incandescent fixtures and others fit in halogen fixtures. Make sure your bulbs fit into your fixtures before purchasing them.
Different bulbs fit into different fixtures, but regardless of the type of fixture, make sure it is placed on a wire mesh surface or hung from the ceiling with nothing between the fixture and the reptile enclosure. Most fixtures have reflective material on the sides or are shaped to help direct the light and heat down into the tank. Other fixtures are open with a wire cage around where the bulb goes to heat all around the fixture.
You'll probably need one of these ballasts for your full spectrum fluorescent bulb unless you decide to go with a compact fluorescent bulb. Some of these fixtures are dual purpose and also have sockets for incandescent or halogen bulbs all mounted on one fixture. These dual purpose fixtures are ideal for small spaces, but make sure the fixture can handle the heat wattage you need to use without melting.
The fluorescent fixture you choose should have a reflector built into it, otherwise, you can just place some aluminum foil to make a reflector inside the fixture to increase the amount of UV rays that reach your bearded dragon. As stated previously, try to place this fixture on the inside of the enclosure so that nothing is between your reptile and the UV rays.
These are different from fluorescent and incandescent fixtures, so don't try to make a halogen bulb fit into one unless the packaging specifically says it will fit.
The typical screw in bulb socket is the incandescent fixture. Most heat lights and ceramic bulbs fit into this type of fixture. Some halogen bulbs are designed to fit into incandescent fixtures as well.
Don't forget to have something to measure your enclosure temperature once your set-up is complete. You should have at least two thermometers - one directly under the basking light, and one on the "cool" side of the enclosure to ensure a proper thermal gradient. For larger enclosures, you should have several thermometers placed throughout your bearded dragon's home.
Now that you know all your options, don't get overwhelmed with the choices that are available to you. Concentrate on what you need, and then decide what specific products you'd prefer, or are best for your enclosure. A source of UVA rays, UVB rays, heat (up to 105 degrees Fahrenheit in the basking spot), appropriate fixtures to hold the bulbs you choose, and temperature gauges are all necessary. Now all you need to do is decide!