Much of the heat from a halide or sodium lamp comes from the ballast. If
you choose a lamp with a remote ballast, you can put the ballast under
your case. It also avoids having the weight of the ballast which can be
40 to 80 lbs depending on wattage supported by your glass-sided case.
Before you ask... Yes, the heaviest ones for a given wattage are usually
the most efficient. Sigh...
Bob Cruder - bcruder@miaco.com