250 watt hps loft grow venting in to room?

After reading around I read that venting in the loft can cause condensation and mould..
Should I put a hole in my ceiling and vent into a room? Will that cause damp?

Whats the best way to vent... Or can I just re vent around the loft.

I'm worried about the heat it will cause so I have to consider venting in to a room plus the mould/condensation/moisture build up.


Thanks

anyone???????????????