If you have access to the engineer in your building (or if you are responsible for the heating plant),  try simply having the heating switched off for an hour, or two or more.  

You may be surprised how long it can take to become noticeable – in some bigger buildings heating plant may run for months unneeded.

From my experience, with a bit of common sense the potential is enormous and easily seen.

All that is needed is an algorithm to better match supply to necessary demand.  Sadly most building lack this most rudimentary technology.