My house has a 15x15 addition with southern exposure, vaulted ceiling. The
addition sits on a concrete slab that has coils running through it for heat.
They are connected to a propane gas boiler which also heats the hot water.
The rest of the house is gas-forced air. The addition can be closed off at
night and is the way I am currently running things.
My question: Am I saving any energy by setting back the thermostat for that
room at night and then reheating the slab in the morning? Round numbers,
lets say the room is kept at 62 from 11pm until 9am. At that point, it is
brought up in two steps, reaching 70 degrees by noon. 11pm back to 62.

I'm afraid I might have slept through the courses on thems, mass, btu etc..

Thanks,