What temperature?
 

At what temperature do you keep your server room? I know that the computers need cooler temperatures to help them run properly, but I'm not sure how low to go.

Managing the temperature of the room wastes a lot of energy. After all, you're cooling the whole room to accommodate your densest rack. Within reason, you don't care what the temperature of the room is, just what's being delivered to the IT equipment. Better to monitor zones or -- even better -- manage each rack inlet temp, making sure each piece of gear operates within its recommended temperature range.

Ken

I suppose it's quicker/less work if you try cooling the whole room down instead of individual racks, right? But I suppose it's worth the effort for the amount of energy saved.

I don't understand why it is important. In my office the department try to keep the temperature between 10 to 16 degree. But my personal feeling is that it is not as much important.