fuck yeah they get hot. once i had a poorly hooked up exhaust duct to my hood with a 400w mh. totally stupid on my part for using no clamps and only duct tape. overnight the ducting fell off. when i went to check the next afternoon, my bulb actually had a big bubble melting outward on the top of it. its been months but to this day, the bulb still works. im lucky the bulb didnt melt thru and cause a fire or somehting like that.