Thermostatic

I would think that common sense would have overpowered your housemates. The energy used to increase the heat by six degrees can't possibly outweigh the energy saved by keeping the heat six degrees lower for eight hours. But sometimes logic fails us in these intractable bickering situations and we need the experts to step in.

In this case, the experts all agree: Turn down the heat when you are asleep and away. Depending on the climate where you live, you can save about 1 percent of your heating bill for each degree the temperature is lowered. That's the financial upside. Turning down the heat when you don't need it also saves natural resources. The fuel spent warming the house back up to 68 degrees is roughly equivalent to the fuel saved as the temperature drops down to 62 (or whatever temperature you choose), according to the U.S. Department of Energy. So the rise and the fall cancel each other out, and the intervening hours are just plain fuel conservation. To shock your housemates even more, tell 'em that the experts also recommend that you turn the heat all the way down to 55 at night and when you're not home. (Don't go colder or your pipes might freeze.)

If you and your housemates own your home, or if you rent it and plan to live there for quite some time, it might be worth your while (and dollars) to install a programmable thermostat. If your landperson pays for the heat, it is definitely worth his or her while. Programmable thermostats can be set to change temperature several times a day, warming the house in preparation for your arrival, cooling it to encourage an early bedtime, and ending the "you forgot to turn the heat down!" fights that are bound to replace your current quibbles. These thermostats generally save fuel. They range in price from reasonable ($30) to strangely costly (over $100) and should be available at your local hardware store.

Warmly,
Umbra