Since metal halides are point sources, the surface of the bulb will be hotter then VHO's (duhhh), but one must take into account the massive surface area a VHO has compaired to MH per watt. Even if 175w of VHO kicks out less heat then MH, you still have to take into account that it also kicks out less light (lumens). So I will ask my question again, does MH kick out more heat per lumen compaired to VHO (or PC).
The reason wy MH's "seem" so much hotter than VHO's is because of the area thing you described. There is actually more total heat given off by VHO bulbs (watt for watt) than MH bulbs. It just seems cooler because the heat is dispersed over a more surface area on the VHO's.
