Reptile & Amphibian Forums

Does anyone have the formula for determing how much heat (in degrees) is produced by a single watt from a light bulb?
In general, don't incandescent bulbs tend to produce more
heat than flourescent bulbs?
I want to see (and know) for myself what the proper watt bulbs I should use to get the optimum amount of heat for a given sized terrarium housing Green Anole(s) in the day as well as at night. Thanks.

The best way is "trial and error". Put a thermometer at each of the basking areas and plug in an incandescent bulb. The wattage has little to do with the amount of heat. The real factors are: ambient room temperature and distance from the light source. I routinely have to change bulbs in the winter when the house is cooler and then again in the spring when it gets warmer. I would suggest starting with a 60 Watt bulb and see if you get a basking temperature of 90 degrees. If not, increase the wattage or decrease it depending on the temperature.

>>The best way is "trial and error". Put a thermometer at each of the basking areas and plug in an incandescent bulb.

Ok. Thanks, will do.

The wattage has little to do with the amount of heat.

#1: See #2 below.

The real factors are: ambient room temperature and distance from the light source.

Yes, that makes perfect sense. I hadn't considered those factors
or their possible (much) more signifigance in solving the optimum heating for Herps problem.

I routinely have to change bulbs in the winter when the house is cooler and then again in the spring when it gets warmer. I would suggest starting with a 60 Watt bulb and see if you get a basking temperature of 90 degrees. If not, increase the wattage or decrease it depending on the temperature.

#2: This sounds like the opposite of what you're saying in #1 above? I *believe* I've remembered a book I have that should have the answer I am seeking.
The book is called "Understanding PHYSICS" - 3 Volumes In One: 1) Motion, Sound & Heat. 2) Light, Magnetism & Electricity. 3) The Electron, Proton & Neutron. (C)1966. The author is Issac Asimov. The publisher is Barnes & Noble, Inc 1993. ISBN 0-88029-251-2.
I got it a few years back in a local Barnes & Noble bookstore in their "Discontinued/Special Value" section for $9.98 (hardcover, too). Well worth that price. Thanks again for your helpful reply. Peace.

E-mail: LizardKing@TechWarrior.Net

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Shark~King

There are too many variables to apply a formula to terrarium heating. Type of substrate, foliage, humidity etc. will all have a minor effect on the wattage of the bulb you use to heat your enclosure. The two major factors are the ambient room temperature and distance from the basking area. You can adjust the wattage depending on whether you have a fixed point for the bulb or whether you can move it closer or farther away from the basking spot. As I stated earlier, the easiest way is to adjust the wattage until you get the proper temperature. I can move my lights closer and farther away from the basking spot(s) by a couple of inches but I still have to change bulbs as the ambient temperatures in the house change with the seasons. I have a range of bulbs from 40 Watt to 100 Watt and have used them all at one time or other. Right now, I have 3- 75 Watt bulbs two of which are directly over the basking areas in my 40-gallon and also 2- 24" fluorescents for UVA/UVB lighting that are within 6" of a basking branch for them. This system produces a basking temperature of 90 degrees and a te,perature gradient from fron to back of 75 to 85 degrees with a drop to 64 at night when everything is off.

>>There are too many variables to apply a formula to terrarium heating.

Yes, I now realize that thanks to your earlier reply to me. I realize that there are other likely more significant factors at work as far as determining the optimum amount of artificial heat to provide a given Herp species in a given sized tank/setup such as ambient room temperature, season of the year, climate of location year round, etc... However, I do think I would like to at least familiarize myself with the actual hard numbers that will let me calculate how much heat will be generated at the source for a given amount of energy expended at the source.
I *do not* trust these companies who are making these reptile UVA/UVB bulbs. I do wonder if they may be using people's unfamiliarity with the science and math involved to basically sell people whatever they want as far as UVA and UVB or UVA/UVB bulbs for reptiles knowing that most people will never take the time to try to understand the underlying science involved in order to make an informed decision on which UVA, UVB or UVA/UVB bulb(s) they need for their herp(s)' enclosures.
It is my opinion that an educated consumer is always better than an uneducated consumer. I mean some of these UV bulbs for reptiles are more than $50.00! For a lightbulb! And one that word is is only good for maybe 6 months tops! I don't know. That don't sound right to me. I wanna see the numbers and at least try to undertand the underlying scientific principles that they're working with to see if there really is anything to them charging as much money as they are for these UV light bulbs.
I mean around where I live they have .99 cents stores where I can buy a 3 or 4 pack of 40W, 60W, 75W or 100W light bulbs for .99 cents. So if someone else tells me I have to spend over $50.00 for a single light bulb and one that is only good for at most 6 months, let's just say I wanna understand why. Not that I entirely doubt these companies. I just wanna be able to check it out for myself. That's all. Peace.

E-Mail: LizardKing@TechWarrior.Net
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Shark~King

To understand about the expense of UVB bulbs, again I recommend the UVB meter owners group on yahoo. BobMac is The Man on understanding and explaining UVB bulb function and production. All your answers on that topic lie with him, and if you can't find it in the files or the archives, you can ask him and he will answer. Truth is, good artificial (non-solar) UVB is expensive to produce, thus expensive to buy. Problem comes when companies make lousy bulbs but still try to charge the same price.
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Torey
Eugene, Oregon, USA
1.1 Uromastyx Geyri (Joe and Arthur)
2.0.1 Uromastyx Dispar Maliensis (Tank, Turtle, and Spike)
1.2 Anolis Carolinensis (Bowser, Leeloo, and Sprocket)
0.1 African Dwarf Frogs (Sheila)
1.0 Betta Splendens (Mr. Miagi)
1.1 Felis Domesticus (Roscolux and Jenny)

A UV (flourescent) gives off very very little heat in regards to heating a terrarium of any size..you HAVE to use a heat source