There are several different options to choose from when deciding how to best provide your pet reptile or amphibian with UVB lighting. This video (and accompanying guide) will help you figure out which option is the right one, for your pet and your wallet!
What kinds of UVB bulbs are currently available for sale?
Many different UVB producing bulbs are available, but 4 different types take up the vast majority of the market share and are widely available. In order of their appearance in the reptile industry, they are linear fluorescent lighting, compact fluorescent lighting, mercury vapor lighting, and metal halide lighting. As technology advances and production costs go down, I'm sure we will see more UVB lighting products available for sale in the future.
Linear Fluorescent Lighting
Pro: relatively inexpensive, fits in widely available fluorescent fixtures, even UVB and visible lighting over a wide area
Con: requires replacement every 6 to 12 months, relatively weak UVB output
Of the 4 UVB products being discussed, Linear Fluorescent Lighting has been around the longest. These linear fluorescent bulbs will fit into most fluorescent fixtures that accept T8 bulbs, from common aquarium hoods to shoplights purchased from your local home improvement store. Linear fluorescents do a good job of producing low to moderate levels of UVB with a decent CRI, and provide decent even illumination across a wide area (up to 48"). While not the strongest UVB producing bulbs on the market, Linear Fluorescent UVB bulbs definitely have their place, and are great for use with animals that have low to moderate UVB needs and can bask within 12-20" of the bulbs. As a general rule, replace Linear Fluorescent UVB Bulbs every 6 months, although many manufacturers suggest these bulbs remain usable for 12 months.
Linear Fluorescent Bulbs come in 3 different strengths and a range of different lengths. In general, 2.0 bulbs are suitable as a 6700K (close to daylight) visible light source, put off very little usable UVB, and are great for use with live plants or those reptiles and amphibians that have low or no UVB needs, such as poison dart frogs. 5.0 bulbs are designed to emulate moderate UVB levels, such as those experienced by animals that live on the forest floor, where the majority of UV radiation is absorbed or reflected by dense plant life above. 5.0 Linear Fluorescent Bulbs are ideal for green iguanas, anoles, and other jungle or forest animals with moderate UVB needs. 10.0 bulbs replicate the intense UVB emitted by full sun conditions, such as deserts. Ideal for popular pet reptiles such as bearded dragons, 10.0 Linear Fluorescent Bulbs (like all linear fluorescent bulbs) drop off fairly quickly in UVB intensity the farther away you get from the bulb, so unless your pet reptile is able to bask 8-12" away from the bulb, a linear fluorescent bulb may not be the right choice for you.
Type of Bulb |
Length |
Wattage |
UVB Output |
Good For |
| Exo Terra ReptiGlo 2.0 | 15" | 14 w | Low |
Poison Dart Frogs Leopard Geckos Crested Geckos Live Plants |
| 18" | 15 w | |||
| 24" | 20 w | |||
| 30" | 25 w | |||
| 36" | 30 w | |||
| 48" | 40 w | |||
| Exo Terra ReptiGlo 5.0 | 15" | 14 w | Moderate |
Day Geckos Anoles Green Iguanas Panther Chameleons |
| 18" | 15 w | |||
| 24" | 20 w | |||
| 30" | 25 w | |||
| 36" | 30 w | |||
| 48" | 40 w | |||
| Exo Terra ReptiGlo 10.0 | 15" | 14 w | High |
Bearded Dragons Ackie Monitors Chuckwallas Veiled Chameleons |
| 18" | 15 w | |||
| 24" | 20 w | |||
| 30" | 25 w | |||
| 36" | 30 w | |||
| 48" | 40 w |
Compact Fluorescent Lighting
Pro: inexpensive, fits in most incandescent sockets, low wattage
Con: short lifespan, inefficient, low UVB output, narrow focus
Compact Fluorescent Bulbs initially got a very bad rap when they were first introduced to the reptile marketplace, as early designs emitted a spectrum that could damage a reptile's vision. That was corrected long ago, and modern compact fluorescent UVB bulbs are perfectly safe to use with your pets. Think of a compact fluorescent bulb as a linear fluorescent bulb that has been wrapped and folded around itself several times. Much of the UVB emitted by the bulb is transmitted back onto the bulb, and is not focused or very directional. Because of this, while using a fixture with a reflector will greatly increase the amount of UVB reaching your reptile's enclosure, Compact Fluorescent UVB bulbs are not horribly efficient and producing UVB radiation. Generally, CFL UVB bulbs should be used at or near your pet's basking spot, so that the animal is exposed to UV while basking. Compact Fluorescent Bulbs are inexpensive when compared to other reptile UVB lighting products, and are self ballasted (they'll screw into most standard incandescent sockets). CLF bulbs are energy efficient, with most models using only 13-26 watts. Compact Fluorescent UVB bulbs should be replaced every 6 months. As a general rule, reptiles or amphibians should be able to bask within 12" of the bulb.
In the past, compact fluorescent UVB bulbs came in the same 3 strengths that linear fluorescent bulbs do. Now, modern CFL UVB bulbs come in 100, 150, and 200 models, with each model progressively emitting higher UVB levels than the model below it. UVB 100 bulbs are approximately equivalent to the former 5.0 bulbs, while UVB 150 bulbs roughly equate to the previous 10.0 bulbs. UVB 200 bulbs are touted as a much more intense UVB source, and reportedly produce UVB that is usable up to about 18" away. Exo Terra has also recently released a 'Reptile Vision' CFL bulb, which is designed to be used in conjunction with a UVB bulb. These bulbs produce a high level of UVA light, which plays an important role in how reptiles and amphibians see their environment.
Type of Bulb |
Wattage |
UVB Output |
Good For |
| Exo Terra Natural Light | 13 w | None |
Poison Dart Frogs Crested Geckos Invertebrates Leopard Geckos Live Terrarium Plants |
| 26 w | |||
| Exo Terra Reptile Vision | 13 w | ||
| 26 w | |||
| Exo Terra Ion Bulb | 13 w | Low | |
| 26 w | |||
| Exo Terra ReptiGlo 2.0 | 13 w | ||
| 26 w | |||
| Exo Terra ReptiGlo 5.0 | 13 w | Moderate |
Anoles, Day Geckos, Green Iguanas |
| 26 w | |||
| Exo Terra Reptile UVB 100 | 13 w | ||
| 26 w | |||
| Exo Terra ReptiGlo 10.0 | 13 w | High |
Bearded Dragons Veiled Chameleons Monitors |
| 26 w | |||
| Exo Terra Reptile UVB 150 | 13 w | ||
| 26 w | |||
| Exo Terra Reptile UVb 200 | 13 w | Intense | |
| 26 w |
Mercury Vapor Lighting
Pro: intense UVB source, produce heat as well as UVB, last up to 12 months
Con: produce heat as well as UVB, require specialized fixture, generally available only in higher wattages
Mercury Vapor Bulbs have been growing in popularity for the past several years. Mercury Vapor bulbs are relatively long lived, with many bulbs only needing to be replaced after 12-18 months. Mercury Vapor bulbs produce intense UVB and heat, making them ideal for full sun animals such as monitors or bearded dragons. Heat production can be a drawback, as well, as this trait renders mercury vapor bulbs unusable in smaller habitats, or with species that require cooler temperatures. Because of their high operating temperature, mercury vapor bulbs are best used in a wire clamp lamp type fixture, which promotes airflow around the bulb and causes heat to dissipate more readily than a typical clamp lamp or deep dome fixture.Mercury Vapor bulbs are also only available in higher wattages than many other UVB sources.
Type of Bulb |
Wattage |
UVB Output |
Good For |
| Exo Terra Solar Glo | 125 w | Intense |
Bearded Dragons, Monitors Animals in large/tall enclosures |
| 160 w | |||
| T-Rex Active UV Heat | 125 w | ||
| 175 w |
Metal Halide Lighting
Pro: Intense UVB and heat production, low wattage compared to mercury vapor bulbs, long life
Con: high cost, requires expensive specialized fixture
Metal Halide UVB bulbs are very new in the US pet trade, but have been used overseas for some time. Metal Halide bulbs produce some of the most intense UVB currently possible, and are fantastic for bearded dragons, veiled chameleons, dwarf monitors, and other sun loving reptiles. It could be said that metal halide bulbs are the next best thing to sunlight! With a relatively low electrical usage when compared to Mercury Vapor bulbs, metal halide bulbs are an energy efficient solution for an 'all in one' UVA, UVB, and heat source for your pet reptile. Metal Halide bulbs are also long lived - up to 24 months according to the manufacturer (Exo Terra/Hagen). Metal Halide bulbs do have an initial high cost, as they must be used with an expensive metal halide fixture, but the bulbs themselves are priced comparable to cheaper mercury vapor bulbs.
Type of Bulb |
Wattage |
UVB Output |
Good For |
| Exo Terra SunRay | 35 w | Intense |
Bearded Dragons, Monitors Animals in large/tall enclosures |
| 50 w | |||
| 70 w |
Things to keep in mind about UVB bulbs
Regardless of the UVB bulb type you choose to use with your pet reptile or amphibian, there are several things to keep in mind so that your pet can receive maximum benefit from your purchase:
1. All UVB sources degrade over time. As the bulb degrades, visible light output can remain the same, but UVB production will begin to drop off as soon as the bulb is first turned on. Once the bulb runs for a certain length of time, the UVB it produces may be too low to meet the needs of your pet reptile or amphibian. At this point, the bulb is serving no purpose other than providing visible light, and must be replaced for the health and well being of your pet. The rate at which bulbs degrade depends greatly on the type of bulb and how long the bulb is used per day, but will also vary among individual bulbs. For this reason, Josh's Frogs strongly recommends monitoring the UVB output of your UVB producing bulb with a UV meter. A great one that's currently the 'standard' for hobbyists in the reptile industry is the SolarMeter 6.2. The chart below has general recommendations on how often to replace Linear Fluorescent UVB Bulbs, Compact Fluorescent UVB Bulbs, Mercury Vapor Bulbs, and Metal Halide Bulbs, based on a usage of 12 hours a day.
2. As the distance between your pet and the UVB bulb increases, usable UVB radiation decreases rapidly. Most bulbs provide UV levels and readings at a recommended minimum distance from the bulb (generally about 8-12" for linear or compact fluorescent lighting, and 12" for Mercury Vapor or Metal Halide UVB bulbs). Make sure to consult the specific manufacturer's recommendations when deciding what UVB bulb to use, and take into consideration the distance between the bulb and your pet reptile before you choose a UVB bulb.
3. Glass and Plexi/acrylic blocks UVB rays, plain and simple. If you are using a glass top on your terrarium or vivarium, or expect your animal to receive any UV benefit via sunlight filtering in through a window, you are sorely mistaken. If there is any glass or acrylic/plexiglass between your UVB source and animal, your pet is not receiving any benefit from the UVB bulb. Some exceptions exist, such as Starfire (low lead) glass or Solacryl (a UV permeable acrylic), but these products are expensive and need to be replaced regularly.
4. Screen can significantly reduce the amount of UVB available to your pet reptile or amphibian. Generally, the closer or more dense the mesh, the less UVB passes through the screen. Use as large a mesh size as possible when selecting a screen top or enclosure for your pet. When most UVB sources report their UVB output at a certain distance, this reading was taken with nothing between the bulb and UV meter.
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