No, Doug is spot on there -- the discussion is about whether to turn the thermostat down at night or not, and the answer (in cold climes like ours at least) is an emphatic "YES!".

But you are also correct -- better insulation always helps, whether one turns down the thermostat or leaves it constant.

The best conservation solution is of course to do both: insulate better, stop air leaks, AND turn down the thermostat at night.

Our heating bill would easily increase by 50% if we didn't turn the home temperature down by 6 degrees (C) at night.

Cheers