>>I tried out a phillips 45 watt halogen flood bulb today. The center of the basking spot (directly underneath the center of the bulb) got very very hot...around 160 degrees, maybe a little more...my digital thermometer only reads up to 160. Then, just 2-3" away from that, the temperature was 113...that's drop of around 50 degrees in a couple inches. What's up with that? Is this normal for halogen floods? I also noticed it didn't produce nearly as much light as the 100 watt zoomed spot bulbs I've been using do (that one gets around 135-140 dead center, and only down to about 115-120 5-6" away from that).
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>>I know they're supposed to be popular bulbs...why is mine so bad? By the way, the basking spot I'm measure on is a flat retes stack.
Halogens do run very hot. You don't say how close the bulb is to the basking spot, but by those numbers I would guess it is fairly close. I usually get a center basking temp of 115-120 at a distance of 16-18 inches from the bulb to the basking spot with a 45 watt bulb and 130-135 at 20-22 inches with a 100 watt bulb.
Greater distances allow the flood to spread out more. At 18 inches the center hot spot is about 4-5 inches across. Also all floods are not the same. Phillips makes at least three different flood type halogens ranging from a beam spread of 30 degrees up to 50 degrees. The 30 degree is sometimes labeled a narrow flood and other times just a flood. The ones I usually find are 40 degree but I have found 50 degree floods from time to time.
A 100 watt spot bulb will put out more light than a 45 halogen bulb, plus the light from a halogen bulb is redder (usually around 3000k) making it appear dimmer in comparison to a cooler (color temperature wise) bulb.
Sounds like you need to raise the bulb higher to reduce the basking temperature and widen out the basking spot. If you are able to raise the bulb up you are in good shape because a 45 watt is putting out more than enough heat for your needs. If raising the bulb is not an option you may not have a setup that allows you to use more powerful bulbs like that.
Watt for watt halogens will never be as bright as fluorescent lights so if you want to add more light after getting the temps right try a tube or compact fluorescent light.
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Mike Wilson
mwilson@fuu.net
