As far as lizards go, bearded dragons are one of the most loved species by keepers and enthusiasts. They are relatively easy to keep, but for the lizard to live long in captivity, the lighting and heating must be maintained closely. You will want to make sure that a beardie's enclosure has a source of UVA rays, UVB rays (simulating the sun's helpful rays), heating, and temperature gauges to monitor the heat level.
Bearded Dragon's Natural Habitat
A bearded dragon's lighting set-up should mimic what the reptile would get in the wild as closely as possible. A natural environment for a bearded dragon is the desert. Beardies in the wild receive ultraviolet light and heat from the sun on a daily basis. In order to best mimic the ultraviolet light in an indoor enclosure, high ultraviolet (UVA and UVB) output light bulbs must be used. Fluorescent bulbs and mercury vapor bulbs are the two sources most commonly used in the pet world.
In addition to making sure that your beardie gets the right light rays, you also have to make sure that this cold-blooded reptile gets the heat it needs. Reptiles normally rely on the sun's heat to regulate their normal body processes. So, for an indoor enclosure, you will need to think about heating it properly. For heat, your best bets are ceramic heat bulbs or mercury vapor bulbs. Although, there are other sources of heat you can use.
Before you get the bulbs, you should think about the light fixtures, and where to affix them. Bulbs should be placed within 12 inches of a bearded dragon. It is important to mount it in an appropriate spot. Make sure it is placed on a wire mesh surface or hung from the top of the enclosure with nothing between the fixture and the reptile.
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.
Aside from direct sunlight (not filtered through a window), there are a couple of different sources that give off invisible ultraviolet rays. Special fluorescent bulbs that fit into fluorescent fixtures give off varying levels of UVA and UVB rays. These full-spectrum bulbs run out of the UV rays before the lights actually burn out, so these need to be replaced per the manufacturer's recommendation, which is usually every six months.
Bearded dragons need an 8 to 10 percent output of UVB rays, which should be clearly marked on the bulb packaging. These bulbs are to be placed overhead and no more than 12 inches from where your beardie can sit or climb in order to soak in the rays. Make sure the bulb is not placed on a plastic, plexiglass, or glass surface. These types of substances will block the rays from penetrating through to the reptile. Research published in 2007 shows that the typical metal mesh screen commonly used for the tops of reptile tanks may block a significant amount of UVB rays as well, but the jury is still out on this theory.
You'll probably need a ballast 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 otherwise it might melt the fixture.
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 number of UV rays that reach your bearded dragon.
Mercury Vapor Bulbs
Mercury vapor bulbs serve more than one purpose for your bearded dragon. They emit both UVA and UVB rays and provide heat for your enclosure. This is a two-for-one. You can use the one bulb to provide both heat and the important ultraviolet 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. 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 to 24 inches between your reptile and the bulb for safety reasons. This bulb is best used for large spaces with a lot of room for your beardie to roam.
Compact Fluorescent Bulbs
These bulbs act the same as fluorescent bulbs, but they can be screwed into incandescent fixtures. These bulbs use less energy than a fluorescent bulb and should last longer, but it's possible the UV may be much too high for reptiles. Be sure to create variety in your bearded dragon's habitat, so that it can regulate UV levels on its own by hiding in shady spots when necessary.
Unless you have a mercury vapor bulb, you will need additional heat bulbs to give the beardies the heat they need. Temperatures needed vary based on the age of the beardie. Babies need more heat and adults a little less. For example, the range for babies is 90 to 110 degrees Fahrenheit and 80 to 93 degrees F for adults. The hottest spot is the lizard's basking area. Also, beardies need separate zones, so if they start to overheat, they can regulate their body temperature by finding a cooler spot. Temperatures should drop by 10 degrees all-around at night.
Fluorescent bulbs do not give off enough heat on their own; beardies will need a supplemental heat source if you are using fluorescent lighting.
Heat bulbs are a safer alternative than heat rocks, which can cause thermal burns. Also, heat bulbs are better than under tank heaters, which makes it difficult to regulate the temperature in the enclosure accurately. Some heat bulbs may also give off UVA rays.
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 ultraviolet rays. So, you will need to make sure you get a full-spectrum fluorescent light. Make sure ceramic heat bulbs are not placed in direct contact with a surface that will melt.
Incandescent Heat Bulbs
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, and nocturnal lights are red (don't use painted bulbs). These bulbs alone do not offer the necessary UVB rays to prevent metabolic bone disease.
The incandescent fixture is a typical screw-in bulb socket. Most heat lights and ceramic bulbs fit into this type of fixture. Some halogen bulbs are designed to fit into incandescent fixtures as well.
The wattage needed depends on the size of the enclosure and if any other heat bulbs are used. The size and shape only matter for fitting in your incandescent fixture.
The shapes of these bulbs usually have 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, but they still do not offer UVB on their own.
Some halogen bulbs fit in incandescent fixtures and others fit in halogen fixtures. Make sure your bulbs fit into your fixtures before purchasing them.
Halogen fixtures 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.
You need to continuously measure the inside of your enclosure to know if your beardie is getting ample heat. 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.
Lighting Requirements for Reptiles. VCA Hospitals.
Michael Burger, R. et al. Evaluation Of UVB Reduction By Materials Commonly Used In Reptile Husbandry. Zoo Biology, 2007.