(Photo courtesy of Jason Hornick (for Express)/Judith Barrow made her rental greener by taking simple steps, including fixing her drafty windows, which allowed her to turn down the heat and air conditioning.)

Judith Barrow knows green. Barrow, 33, is writing the Washington Sierra Club’s guide for sustainable living, which offers tips for saving energy and reducing your home’s carbon footprint.

But even Barrow wasn’t sure about the energy efficiency of her own apartment. So last February, she invited Washington’s Department of the Environment to do a free audit on her U Street townhouse.

“They look at different parts of your house and tell you simple things you can do in your kitchen, your living room, to make them greener,” she says. “We went through the house segment by segment to see what could be done.”

Barrow appreciated the professional help.

“It’s more challenging for apartment renters,” says Sacha Cohen, who used to blog about green living in the District. “You can’t do as much to change your space.”

Renters often can’t make big changes that owners can, such as switching out appliances or re-insulating the walls. Every landlord has different restrictions, but there are simple fixes that even renters can make.

Based on recommendations from the audit of her three-bedroom apartment, Barrow began doing some of those simple things. She started keeping her refrigerator and freezer a bit warmer (the EPA recommends 37 degrees for your fridge and 3 degrees for freezers). She also filled in any draft in the windows around her home to keep the heat and air conditioning in.

“I’m always trying to find ways to keep down costs and reduce my energy consumption,” she says. And the changes paid off, lowering her monthly energy bills by about $40, she says.

Another simple fix for the environmentally minded renter: Buy plants. Indoor houseplants naturally improve an apartment’s air quality. Larger leafy bushes can also be placed in front of windows to block out sunlight, keeping your space cooler in the summer.

There are lots of easy ways to keep your home insulated to reduce energy use — with the added bonus of lowering utility bills. Cohen recommends keeping blinds closed in the summer and buying rugs or other insulators to protect against winter drafts.

If you’re more worried about wasting food than wasting energy, consider composting. It isn’t impossible, even in a tiny apartment.

Urbanites without a yard or garden can consider Compost Cab, a weekly service that picks up your food scraps from your home and uses them to make compost for non-profit farmers. The service costs about $8 a week, and they provide a bin for you to fill up between pickups.

For Sahiba Chopra, 23, greener living was as easy as changing what she bought at the store.

“I started using products that are more organic,” says Chopra, who lives in a three-bedroom apartment in Bethesda. There are a variety of organic household cleaners that keep harmful chemicals out of your house — and out of the environment. Keep an eye out for Mrs. Meyers or Nellie’s Organic products, and look for biodegradable trash bags.

In addition to buying green products, try to create less waste by buying fewer products. And when you’re looking for something new, check out Freecycle or Craigslist for gently used products.

Energy efficient lights (such as LED or CFL lights) are another way to cut down on how much you buy. They last longer, meaning you can buy fewer.

“I always look for ways to save money, so I got energy [efficient] lights and things like that,” Chopra says.

Barrows and Chopra have teamed up to help other Washington-area renters. “We’ve come up with creative ways to help D.C. residents be more aware of their energy uses,” Chopra says. They put together an energy efficiency starter kit, which will be distributed at Sierra Club meetings.

You don’t have to wait for the kit. Clever ideas for greening your apartment are hidden right at the hardware store.

Anne Stom, who owns Annie’s Ace Hardware in Petworth, says her favorite green purchase is a Sodastream (it’s about $75), which carbonates water or other juices at home and cuts down on plastic bottles.

“I’ve seen the benefit at the front end, not lugging all the bottles in the house,” she says. “But I also see it when I take out our recycling.”

Stom says she’s seen a growing interest in her green products from D.C.-area residents. “Many young people have children, they have pets, they want safer stuff,” she says. “The people who live here are good stewards of the world.”