What is your opinion on closing off portions of your house to save on utility bills?

This has been kind of a running disagreement between my husband and me. I say close off (via door or curtain, whatever) those rooms that you don’t spend that much time in so that you are only cooling / heating the area that you spend the most time in (the living room.) HE says that the AC / Heater works more “efficiently” if the house is open all the way around. The heating and air guys say the same, BUT my experience says it’s not so.

The way I figure it, the majority of the house doesn’t need to be comfortable. In the winter, take a warm shower in the chilly bathroom. Use extra blankets on the bed. The stove heats up the kitchen if you’re in there cooking…..and so on.

In my house, the thermostat is in the living room, where we “live” when not at work. From the living room we can “block off” the rest of the house, which I do via two curtains. (Really, it’s not as redneck as it sounds! They’re nice curtains! Kind of gives a Roman-tent feel to the house! IMO…anyways…) two days ago I took the curtains down to wash them. (Haven’t had a chance to wash them though, because our washer and dryer are on the back deck Which IS redneck, but only temporary as we’re laying new flooring) Since then I’ve noticed that I can’t keep my “living” area as cool at the normal thermostat settings, and I’m tempted to turn it down to a cooler temp/more utility use. This, to me, proves me right.

So, what say ye?