What a timely question! As winter begins, I have a related query for a smart mustachian or two. Our new single-story house is a great room style. The living room, dining area and kitchen make up about a third of the square footage. This area has 14' ceilings. We have gas forced-air heat. The house is about eight years old, so the windows are energy-efficient and the insulation is good. We can't let the house get too cold, as his mom lives with us and she has Alzheimer's. Would it be more efficient to keep the heat set at a given temperature (say 68) all the time? Since the room has such a large volume, it takes quite a bit of time to heat it up, but once it gets warm, it stays comfortable easily. MIL and I are home during the day most days. Conventional wisdom says to turn it down at might and when you leave the house, but most houses don't have 14' ceilings. Conversely, it kills me to think of leaving the house with the heat running. Anyone out there have an expert opinion they're willing to share? And no facepunches on the clown house, please. We bought it so his son, mom and an eventual caretaker can live with us. It's walking distance to DH's work.