Currently I have ten 60W incandescent light bulbs heating up my room, very little ventilation, and no ideas on how to stop them from making the room so very hot. If I had other lighting option, I would've switched to them by now, but I have to work with what I have.

How can I prevent the light bulbs from heating up my room, so that I don't lose too much light (at most 20% brightness loss is acceptable), and the lamps don't overheat, or otherwise become a danger?