Conserve Heating and Cooling

Air-conditioning packs the biggest punch for dorm power usage, and if your room has individual temperature control, you can set it a few degrees higher to help cut back on how much energy the cooling system uses. Never leave a window open when an air conditioner (or heater) is running, and on hot, sunny days, keeping the blinds or curtains closed will block many of the sun's warming rays. In the winter, this will help keep the cold out, too. Year round, report broken windows, cracks in doorways, or any damaged thermostat controls to the university maintenance department.

Light Efficiently

Switch off your overhead light, desk lamp, and any other lights every time you leave the dorm. To take your environmentalism a step further, if the bulbs provided aren't LEDs, consider swapping some in. LEDs are 85 percent more efficient than old-fashioned incandescents and last much, much longer. If you decide to decorate with that dorm room staple, a string of holiday lights, make sure those are LEDs too. (Find tips on how to shop for energy-efficient bulbs here.)

Unplug Everything

The average dorm room consumes 30.2 percent of its electrical energy while you and your roomies aren't there, according to one study. That's because appliances continue to draw power from electrical outlets even when turned off or idle. A power strip or surge protector helps avoid this: You can plug all your appliances and devices into it, then easily stop them from drawing power with one switch.

Don’t Make Your Screens Work Too Hard

If you have a television, look for an energy-saving feature called Automatic Brightness Control. It automatically adjusts the picture brightness level to the amount of light in the room. Game consoles can be huge energy drainers if used to stream videos or if constantly left on. Instead, stream with apps already on your TV or with a streaming device (like Roku or Apple TV), which require one-fifteenth the energy. Keep the auto-power-down feature enabled so your game console doesn't consume power when you aren't using it.

Desk computers and laptops are college necessities, and as with your gaming console, you can typically program your computer to go into a low-power standby mode when you're taking a break. Look for an energy-saving or eco-mode.

Shopping for a new computer? Check out this website to find one that is certified by Energy Star to be energy efficient. (Any printer or mini-fridge you buy should be similarly certified.)

Reduce Water Use

If you have a dishwasher in your room or suite, run it only with a full load; the same goes for doing laundry. Wash clothes in cold water and consider using a drying rack instead of an electric clothes dryer, which often uses as much energy as a new refrigerator, dishwasher, and clothes washer combined.

If you live in an apartment-style dorm, more bonus points to you if you add a faucet aerator to your sinks. Aerators can reduce water flow to 1.5 gallons per minute or less from the standard flow of 2.2 gallons per minute. They are inexpensive and easy to screw onto the nozzle of your faucet, and they save energy by reducing your hot water use.

Save the Food

An NRDC study found that about 40 percent of food is wasted in the U.S., which leads to a lot of emissions from food rotting in landfills. (One such gas is methane, a greenhouse gas that is up to 80 times as effective at trapping heat as carbon dioxide). Do your part to help keep food scraps out of the landfill. Don't pile a tray with more food than you can possibly eat at the dining hall and keep a set of reusable containers on hand, in case you find yourself with extra slices from your late-night pizza delivery. With leftovers you can't store, it's best to toss them into a compost bin if there's one on-site or nearby; some cities host farmers markets where you can drop off composted food for free. You could even start a composting club or, if your roommate agrees, make your own composting worm bin.

Create a Movement

With communal spaces and shared amenities, it can be hard to regulate every part of your energy use. Talking with your resident advisor (RA) about ways to increase dorm energy efficiency is a great way to make meaningful change. You could also join—or even start—an environmental club or energy efficiency council on your campus. When you join together with other student activists standing up against climate change, your impact on greening college life will go well beyond those dorm room walls.