Re: Set to a range
I've not yet encountered a system that lets you do that explicitly, but they must exist, surely.
They most certainly do exist, and the can work well, particularly if you have a building designed to maximise the benefits of passive heating and cooling (like the one I work in). Our Building Energy Management System (BEMS) has powered heating and cooling at its disposal, but within the normal range of temps will automatically open and close windows on different levels to control temperatures through passive airflow. Energy use is low, comfort is high, and this in a building built twenty four years ago
But most office (and DC buildings) weren't designed in this way, and if they are in high density urban environments then passive cooling doesn't work as well due to urban heat island effects and sometimes due to poor external air quality. It can be done (eg The Gherkin), but anybody who knows the City will be aware that most of the buildings are drab, high density, actively heated and cooled prisons, reflecting the fact that the architects and their clients didn't care. Add in a cheap BEMS that does aim for a single figure temperature, and you have a recipe for discomfort and high costs. Retrofitting actively controlled passive ventilation is virtually impossible if the building isn't designed for it at the construction stage.
A BEMS can be (and usually is) a large scale equivalent of a dumb domestic thermostat - so cheap and crap. A good one is a sophisticated multi-million pound private SCADA network, using extensive sensors and actuators, keeping temperatures in a controlled band, and linked into active heating and cooling that operates in a duty-assist role. The most advanced can even integrate a standby power system to minimise grid costs or sell power into the ancillary services power market, or to harvest the subsidies associated with on-building PV.
As is always the way, the reason things aren't any different is because the executives have a tantrum if their offices are uncomfortable and that gets fixed, but they don't give a tinker's cuss about the peasants. The vast cost of prime estate property dwarfs the energy costs anyway, and they just HAVE to have a premium London office (or New York, SF, Frankfurt, Tokyo, et al), full of minions to justify their self importance. And that usually means speculatively built or legacy buildings, and all the vileness of the metropolitan environment.