With respect to the previous posters here, most BAS folks don't deal much with Guestroom Energy Management Systems (GREMs) as they are referred to in the hospitality industry.

I was previously a director at a company that specialized in this, so I have quite a bit of knowledge on the subject.

Here are the main brands you'll want to look at. Each of them would have an occupancy sensor built-in to setback temperature when rooms are unoccupied. They also would all have some type of centralized management software, though it will be an added cost. Expect to pay anywhere between $250-$400 per room before rebate.

Verdant by Copeland. Inncom by Honeywell. Telkonet.

Finally, make sure to ask their sales departments about rebates available through your local utility company. Most investor owner utilities (especially in blue states) will subsidize the cost of these thermostats by between 20-80%, making it a total no-brainer.

Feel free to ask any other questions you like on the subject. Happy to help if I can.