I've just joined the ranks of Sky+ users - (previously just had the standard box) so I'm not that familiar with what to expect.
There's one peculiarity that I'd be pleased if someone could clarify as to whether this is normal &/or how it can be changed.
In normal operation, if the box is turned to standby using the remote, the fan (& possibly the hdd) continues to run and the box becomes quite hot and stays hot. However, if the box goes into standby automatically after recording a programme, the fan no longer runs and the box gets cool.
I've tried asking Sky's technical people, but they were hopeless - they just said the fan should run all the time - what a joke.