I am almost never home and barely use electricity when I am. My neighbor’s arcade of fancy new electronic equipment is constantly in use, yet he pays less than I do! What gives?
One likely culprit is your refrigerator. If your fridge predates 1993, when national efficiency standards took effect, you could be paying as much as four times the national average cost of running a fridge, which is $80 to $90 a year. “That alone could be the difference,” says John Nall, manager of the residential efficiency program for Southern California Edison.

The refrigerator is a home’s hungriest energy eater (after swimming pools and HVAC — heating, ventilation and air-conditioning — systems). Consider an upgrade to a model that has been certified as energy efficient by the government (look for the Energy Star rating). In the meantime, keep your dinosaur defrosted and no colder than 40ºF.

Is it cheaper to leave lights on rather than switch them on and off every time someone enters and leaves a room?
Nope. And if you can’t train all family members to switch off lights when not in use, consider installing motion-activated switches, suggests Paul Miles, manager of marketing and technical services for PECO, a utility that delivers electricity and gas to southeastern Pennsylvania. The same “Turn it off!” rule applies to computers.

Do my appliances use up energy if they’re just plugged in but not turned on?
Surprisingly, many do. Anything with a glowing light, LED or digital display, or “memory” (this includes phones, message machines, VCRs and stoves with clocks) requires a steady, if tiny, stream of juice to keep running.

Is it more economical to turn off my home air-conditioning when I’m at work, or to keep it running so I don’t have to blast it later?
Program your home cooling system to stay at a suboptimal range (80ºF is good) during the day, and to switch to the temp you like one hour before you’re due home. If you turn it all the way off, “you have to cool off all the furniture and walls” to get back to a comfortable temp, Nall explains. Also, program your system to deliver a slightly warmer temp when you’re asleep. “Everyone should have a programmable thermostat,” says Nall.

If I want to steam some vegetables, is it cheaper to nuke ’em or to cook them on the stove?
If your burners are electric, the microwave is probably the better electricity bargain. Microwaving is also usually cheaper than using a gas range, but might not be if the cost of your natural gas is low and your microwave is old and inefficient.