I just read some interesting material concerning the distance you should place your lights from the basking shelf of the Iguana.
In my opinion this "rule" makes it rather simple and takes out the guess work.
This information is taken directly from the UVB Meter Owner Group and was written by Bob Mac.
I seem to be getting my digest a little slow. When I read this thread I thought I would see the magic and all important answer to this question.
All lamps that throw off heat should be set according to the HEAT they emit rather then anything the box says. Regardless of them being UVB (mercury vapor) lamps or otherwise. Please disregard any manufacturer suggestions and use this rule always!
I have found that all 100wt and higher lamps need to be at least 14" from the basking shelf in a ambient air temperature of 70+ degrees.
There are lots of variables that can enter the equation for distance needed for various style lamps (flood, spot, spot-focus, par38 flood, ect) but if you keep the HEAT as the deciding factor, your pet will be safe.
That's an easy equation to go by, but when you take in the variables it opens a whole other door. I don't know anyone who doesn't have some kind of variable to work in.
The color of the shelf is one variable...or whether it's a solid shelf or wire. Is it covered with astroturf or solid wood w/poly coating?
Is the enclosure solid on all sides, open-mesh doors or open-mesh on all sides?
Is there a humidifier in house, in enclosure or is it just misted several times a day?
Is there an air register on the floor near the ig or a fan built in for circulation in the enclosure? Is there a window air conditioner or swamp-cooler pointing towards the enclosure or free-roaming basking spot?
It's enough to make us crazy...as ig owning is apt to do.
Checking the temps regularly is really the only way I know to keep up on these crazy things...
While in NC I picked up a nifty non-contact thermometer. It is simply amazing! (Radio Shack $30). <Dominick> ***Re Dominick's new thermometer. They retail for $49.95. You have to watch the Radio Shack ads to find it one sale for $29.95. They seem to put it on sale several times a year, so you've got to grab them when you can, otherwise it's a pricey $50 gadget...altho still worth it. it requires a funky little battery that is not included, so don't forget to pick one up while you're there. You can see the product description at <http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F010%5F005%5F001%5F000&product%5Fid=22%2D325>