ok,ive started 12/12 from seed im on day 5 under 150w hps, i got a cupboard 60x60x120 in a spare room that is 2mx2mx3m and temperatures are just crazy in there
HPS balast is like a little heater after few hours, and i havent even installed doors to my cupboard i got only desk fan blowing air and temperatures are around 80:/
I got 5 plants there atm, would i be better off with 2x125w red spectrum cfl or one 250w?
i believe youre using cm and meters.... blah!!! anyways, assuming that ive done my conversions right your cabinet is 2 feet square and 4 feet tall. with that little of space even large watt cfl's are gonna get hot. i run 13 23watt cfl's in a space roughly the same size and my temps are between 70f ( at night ) and 82f ( at day ).
assuming that you are using a hood with the ballast built into it, what you may want to try... mount the hps at the top of the cabinet with a couple inches above it. then seal it off around the bottom of the reflector. this will help keep the radiant heat from the hood out of your actual grow space. vent the top of your cabinet above the mounted light well and it should help you a lot.
in the pic attached you can see what im talking about. the box on the left is your cabinet standing in front of it. the blue part is the reflector and the red part is the attached ballast. the orange rectangle under that would be a shelf with a square cut out to expose only the bottom of the reflector and not the ballast, as the picture on the right shows you looking up at the light from inside the cabinet. see how just the glass is exposed.
youll have to raise the plants to the light, but it will definately help your heat issue. with cfl's youll have to have lots of ventilation. i run 2 100cfl cpu fans for intake and exhaust and have a fan oscillating on the inside.