Posted: Sun Mar 21, 2010 1:52 am
I think Sull was trying to say: Self-Balasted Mercury Vapor Bulbs, (MVBs) emit both heat and UVB light, and are very good bulbs, assuming a few things:
a.) You can put it at minimum 12" away from the basking area
b.) The bulb/fixture are not frequently moved or jostled
c.) You have the ~$50 to pay for one.
The deal is they produce LOTS of heat and LOTS of UVB, so the normal range you need one from the basking area is 12-18 inches, depending on how hot you need the basking area.
Second, the self-ballasted bulbs (there's another variety called "externally ballasted", but they produce no useful amount of heat) have a filament in them that is relatively fragile, so if you're moving the light fixture a lot, there's a good chance it'll break & you'll have a broken $50 lightbulb.
The cost isn't TOO extreme, but usually more than you'll pay for another UVB light. This is generally offset by the quality and extended useful lifespan of a MVB compared to another flourescent that probably outputs less UVB to start with, and will lower it's output more quickly.
SO it sounds like what you were discussing is a MVB, but whether or not you will get a lot of use out of an MVB depends on your setup & how much you want to invest.