Most of the major contributors to residential energy bills are operated by thermostat. Your heating and cooling system, water heater, refrigerator, and freezer all run as necessary to satisfy a thermostat unless you turn them off. Even when turned up to 85 degrees, a central air conditioner may run as much as three or four hours out of a 24-hour period on a really hot day.
Many appliances, even when switched off, continue to consume energy. For example, your television has a power supply and considerable circuitry designed to receive a remote-control signal and quickly power up. The only way to stop this usage is to unplug it. There are dozens of devices in your home, like DVD players, coffee makers, microwaves, alarm clocks, automatic sprinkler systems, and satellite receivers or cable boxes that continuously consume energy, whether you are home or not. Remember, just because you’re not there does not mean appliances are not running and just because they are switched off does not mean they are not consuming energy.