Hi Tim
Thanks for your comment. In fact, almost everyone agrees that lowering the temperature in your house for a significant period of time more than makes up for any cost associated with bringing your house back up to your desired living temperature. (In fact, any cost of restoring the temperature is off-set by the energy saved allowing the temperature to drop in the first place).

People still raise this question, but most experts agree that programmable is the way to go. Just limit the Overrides!

For more on this, check out How Stuff Works, or Umbra Fisk on Grist.