In the previous post, we have talked about iguana’s cage, its sizes, requirements and how to make your own DIY iguana enclosure. But after you have bought or built an iguana cage, you will need to set up lighting, heating and humidity to the optimal conditions. In this post, we will guide you through the lighting, heating and humidity setups for your iguana’s terrarium, recommend the products that you might find suitable and answer some questions.
Why is lighting important for iguanas?
Lighting is very crucial because iguanas need UV light to produce vitamin D3. Vitamin D helps with absorption of calcium. Without enough vitamin D or calcium, your iguana will risk having weak bones and immune system. Light source will also tell your iguana about time of a day and will promote interest in eating. There can be two types of lighting – natural unfiltered sunlight and artificial lighting.
Why is heating important for iguanas?
As we have discussed before, iguanas are tropical lizards that love basking and raising their body temperatures.
But why is it so important? Iguanas heat themselves because it is a key factor to their healthy digestion and immune system. Without high temperatures, iguanas are unable to digest their food or absorb important nutrients. Without heat they become weak, sick and lethargic.
Lighting and heating. Which lights to use for iguana’s terrarium/cage?
Iguanas are tropical lizards and spend many hours a day basking. In the natural habitat, they bask under the sun, and the unfiltered sunlight is the best source of heat and light. If you live in a warm or hot place, keeping your iguana outdoors in a wooden and wire cage is the best option.
This way your iguana will be able to bask and receive the natural sunlight. But if you live somewhere colder, you will need to place artificial lighting in your iguana’s cage. Of course, if it is hot enough in summer, you can take your iguana outside for basking (in a cage, pen or even leash) or place it near an open window.
Please remember, that glass terrariums filter the sunlight by at least 30%, so artificial light is important with this option.
How much light and darkness do iguanas need in a day? And which temperatures do iguanas need?
12:12 hours of light and darkness is optimal for iguanas. It can also be 13 hours of light and 11 hours of darkness. The best way to control the light cycle is to install a timer, and it will turn the light on and off automatically. A very useful device is a heat and light power center like this, which will take care of light and heating devices.
Make sure to create a basking spot and a cooler spot where iguana can move if it gets too hot.
What is the ideal temperature for an iguana?
- In the basking spot, ideal temperatures for iguanas should reach 96-100 degrees (35.5-37.7 Celsius).
- The air temperature in iguana’s cage during the day should be around80-85 degrees Fahrenheit (26.6-29.4 Celsius). This is also called background temperature.
- A cooler spot in the cage should have temperatures of 78-80 degrees Fahrenheit (25.5-26.6 Celsius) for your iguana.
- At night, temperatures of 70-75 degrees F (21.1-23.8 Celsius) for adult iguanas and 73-75 F (22.7-23.8) for hatchling and younger iguanas.
- Your iguana will die if the temperature in the tank goes over 113 Fahrenheit (45 Celsius) or under 40 Fahrenheit (4.4 Celsius).
Iguana thermometer supplies
Install two thermometers at different sides of the terrarium to make sure the temperatures are optimal. This thermometer is digital, and you should choose digital one over an analog for more accurate readings.
What is more, a good thermometer has a remote wire probe so that you can put it under the basking light for an accurate reading. You can also choose a digital hygrometer + thermometer combo, also with a separate remote wire probes.
Thermostat. If you are using an under tank heater, thermostat will be able to control the temperatures, so that terrarium doesn’t overheat.
If you find it hard to keep the temperatures higher in the cage and to create a hot and cool spots, you can add ledges. Ledges will help create temperature differences in the cage to help your iguana cool down when it’s too hot.
Photoperiod – changing seasons
When seasons change, photoperiod also changes. Photoperiod is the time of daylight in a day. In summer, days are longer, and in winter – shorter. If you keep your iguana outdoors all year round, then changes will be natural. But if you keep your iguana indoors, you will have to mimic the photoperiod of the season.
For this, check sunrise and sunset times and set the timers. Keep changing the times gradually when changing seasons by few minutes daily. Photoperiod is important and affects iguana’s mood, breeding and general wellbeing.
Iguana lighting guide
Having your iguana outside all the time (where you have the sun most of the day as well) will be hard to achieve. That is why most iguana and other lizard owners use artificial lights for controlled light (and heat) source.
Using both artificial light and making most of natural unfiltered sunlight is the best option if your winters are chilly or cool and summer quite warm (at least some days).
Don’t only count on natural sunlight reaching your iguana (especially in a glass cage) indoors, as it gets filtered.
Artificial lighting which emits UVA and UVB lights is important for health and digestion of your iguana. UVA light accounts for most sun exposure and promotes healthy behavior in iguanas. And UVB light spectrum helps produce vitamin D3 in iguana’s skin. Vitamin D is also closely related to absorption of calcium.
What light does my iguana need?
- Incandescent light bulbs – both light and heat
- UVB light bulbs or fixtures like this – both UVA and UVB light only
- Mercury vapor lamp – premium light bulbs for both UVA, UVB and heat
- Ceramic heat emitting bulbs – for heat only
- Full-spectrum light bulbs (make sure these are for reptiles, and not for plants).
- Heating cable like this might be necessary to heat the bottom of the tank in very tall and large cages.
- Coiled light bulbs are not recommended, as they have been proven to stop emitting UVA and UVB lights after some time.
- You will have to replace light bulbs or fixtures every 6 months or less.
- To decide on best heat bulb wattage, you will have to measure temperatures, change the distance and wattage – it will require some trial and error. Heat bulb wattage will depend on iguana’s cage size, and if you are using any other form of heating on the bottom of the cage.
Iguana UVB lamp wattage, and what distance from the bulb to iguana is ideal?
The wattage of UVB bulbs needed will depend on iguana’s cage size.
- If your iguana has a small cage, 1 UVB bulb or tube of 15-20 watt will be sufficient.
- For a medium sized cage (juvenile), 1 UVB bulb or tube of 30-40 watts will be more sufficient.
- For a big cage for an adult iguana, you will need two 30-40 watts bulbs.
- The intensity of UVB light will depend on how close or away you put it from your iguana.
- For one 5.0 ReptiSun or ReptiGlo bulb, place it around 15-25 cm (6 – 9.8″) away from your iguana. If there are two 5.0 UVB bulbs, place them around 30-35 cm (11.8-13.7″) away from your iguana.
- For one 10.0 UVB tube like this, place it around 20-30 cm (7.8-11.8″) away from your iguana. If there are two 10.0 UVB bulbs, place them around 35-40 cm (13.7-15.7″) away from your iguana.
Do iguanas need a heat lamp at night?
- Make sure to heat iguana’s cage at night if temperatures in the house drop below 73-75 F (22.7-23.8 Celsius).
- For keeping your iguana warm at night, use ceramic infrared heat emitting light bulbs like this. They will only produce heat and no light, not interrupting the daylight cycle.
- Don’t use heating rocks as they might cause burns to your iguana when it lays on it to heat itself. This can cause serious damage to the skin and even internal organs. Heating rocks don’t provide light but only heat – they only become very hot in a short period of time.
- Another way to heat the terrarium at night is to use heating pads or heating cable on the bottom of the cage.
- Iguanas can see red lights, as well as blue, black and other colors. Do not use colored bulbs in iguana’s cage at night.
Should I turn off my iguana light at night?
Yes, make sure to place bulbs on a timer to turn them off at night. 12:12 photo-period means that the bulbs that produce lights will have to be turned off, or your iguana’s sleep will be disturbed. If the cage and the house gets colder than 70-75 degrees, then make sure to turn off lights and to have a ceramic heat emitting bulb that produces only heat.
Please remember!
If you are using the light bulbs, getting reflector domes is very useful to cover the light bulb and create a basking spot. You must place reflector domes above the screen cover. 
If your terrarium doesn’t have one, you can purchase it and install on top of the terrarium. For a mature iguana, it is advised to get a dual domes for two light bulbs (or use a large fixture), so that all parts of the body are under the light.
If you are getting a tube light, make sure to get the same size hood to house it in.
You need to ensure that all hot surfaces and light bulbs are out of reach or covered, as many lizards burn themselves. This happens more often than you might think, as lizards will touch and push themselves to the uncovered light bulbs and burn themselves.
And another important thing…
While iguanas love basking for many hours a day, they also need a spot where they can cool down. This is why you will need to create a basking spot with lights and branches, and another spot where they can hide or just cool down (with lower temperatures). Overheating can also become a problem.
Why is humidity important for iguanas?
Right humidity levels are very important because they help mimic the natural environment for your iguana. 
Setting the humidity levels to optimal and spraying or misting your iguana will also help with skin shedding.
You can always supplement iguana’s humidity levels by misting your favorite lizard with water or even giving it a bath. Misting once in a morning and once in the evening or even occasional bath can help with shedding and stabilization of humidity levels.
What humidity levels should you set in iguana’s vivarium?
The optimal levels for humidity in your iguana’s cage is 65-80%, but 70 to 80% is the best. Use a digital thermometer and hygrometer combo gauge to check for humidity levels and temperatures with a remote wire probe for accurate readings.
How to increase humidity levels in iguana’s vivarium?
Use a reptile humidifier in iguana’s cage to increase humidity levels if they drop low (especially in dry places). Another way to increase humidity levels is to place another water dish in the enclosure (water will evaporate, increasing humidity or your iguana might soak in it).
How to decrease humidity levels in iguana’s vivarium?
If you live in a humid area and the humidity levels are too high, you will need to decrease them for your iguana. You can do this by using a dehumidifier or allowing fresh air inside the terrarium by opening the door or lifting the screen cover.
Hope you have found this post on lighting, heating and humidity useful.
In the next articles, we will talk about accessories in your iguana’s cage and grooming. You will find many interesting posts on iguana care on this page.