Haven't come across this utility before, so I thought I'd give it a try. It sounds like a good idea. This software puts your PC to sleep or hibernate provided that certain predetermined conditions are met. The configurable parameters include CPU usage, disk usage, network usage, user idle time. If all of the conditions are met, then you're put to sleep. WinSleep is looking for signs that activity has stopped, or at least fallen below the chosen threshold.
You set up one or more schedules to control when the policy will become enabled. You set trigger conditions for each schedule. WinSleep call these schedules 'sleep policies'.
WinSleep has a simple, graphical interface showing live system information. It also shows a graph displaying historical events e.g. when was WinSleep awake, asleep, when the schedule was active.
When trying WinSleep, I found that the CPU activity generating during the process of going to sleep actually stopped the sleep happening. The CPU threshold was set at 12%. I increased it to 14%, which was enough to allow the sleep to commence. WinSleep talk about this in their help file.
This utility works with Windows 7 and upwards.
You can get a free code for this at http://www.giveaway-club.com/
for another 26 hours or so last time I checked. They say it's a lifetime license.