Our efforts to tread lightly on the planet often revolve around how we commute, what we eat and how we set our thermostats. But the way we furnish our homes has a surprising impact, too.

According to the National Wildlife Federation, furniture manufacturers are the third largest consumers of wood, behind the construction and paper industries. Meanwhile, the Environmental Protection Agency estimates Americans disposed of 12 million tons of furniture in 2018 — 80% of which ended up in landfills — up from 2.5 million tons in 1960. That's a lot of old couches left on the curb.

In recent years, the furniture industry has begun to resemble the "fast fashion" industry — encouraging consumers to buy cheap items and replace them within a year or two. But it doesn't have to be that way.

1. Repurpose your old furniture

The first thing to consider when shopping for new furniture? Not buying it at all, says Laura Hodges, a Maryland designer with certifications from the Green Building Council and Sustainable Furnishings Council.

"When I meet with a new client, we always start by asking if anything even needs to be purchased," she says. "If we're not [buying] anything new, there's no energy used to make it or ship it, there's no need to harvest materials, and there's no waste — and if you can save an old item from a landfill, even better."

Margot Guralnick, an editor at the eco-friendly blog and publisher Remodelista, also nudges homeowners to re-use: "You may have furniture in your basement or your attic, or a perfectly good sofa sitting unused in an office," she says. "And remember, a desk doesn't have to be labeled a desk — a big table could work as a desk, and a stool could become a nightstand." (You might even ask friends or relatives if they're willing to part with furniture collecting dust in their basements.)

From there, it's not terribly hard to give an outdated or well-worn piece new life. Take the old couch to a local upholsterer or furniture refinisher; put a new coat of stain or paint on an old table.

2. Buy vintage or antique furniture

The next best option is to buy used furniture. "A lot of older furniture is better made than the mass-produced items in many stores today," Hodges says. "Back in the '50s, '60s and '70s, furniture was designed better and solidly built, often by hand. Those items tend to last longer, which is why they're still around."

You can find high-quality items at vintage and antique stores, thrift shops and yard sales. Guralnick also recommends Craigslist, eBay, Etsy and Facebook's "buy-nothing" groups. She advises using the sort-by-distance filter when perusing those sites, so you don't fall in love with an item that's 600 miles away.

3. Buy new furniture that's built to last

If you decide to buy new, says Hodges, "the first thing to do is identify companies that make things that last." She recommends American-made items with hardwood frames, kiln-dried wood, eight-way hand-tied spring systems (found in couches and chairs), and hand-applied finishes.

"If you find a piece of furniture that is technically made of all 'sustainable' materials and it falls apart in a few months, that's not sustainable," Hodges says. "Even if it's made of recyclable steel, it doesn't matter unless somebody actually takes the sofa apart and has every piece of metal recycled and every natural fiber composted. If it ends up in a landfill, you haven't solved any problems."

4. Look for the right materials (and avoid the wrong ones)

Just as a lot of food is labeled "fresh" or "natural" with no real significance, furniture manufacturers may insist their products are "environmentally friendly" or "sustainably produced" with scant evidence. But you can do your own homework.

For wood pieces, check out the Wood Furniture Scorecard, produced by the Sustainable Furnishings Council and National Wildlife Federation. The annual list ranks dozens of companies based on publicly available information regarding sourcing and transparency. Websites such as Remodelista and Minted Space also curate collections of furniture makers with a strict focus on sustainability.

Sarit Marcus, founder of Minted Space, notes that it's best to make furniture out of fast-growing trees such as mango and rubber trees, as well as plants such as bamboo, cane, rattan, reed and seagrass. Avoid slow-growers like Brazilian mahogany, Canadian white cedar, cherry, maple and oak, which take decades to mature.

The next big concern is the use of harmful chemicals. According to the Natural Resources Defense Council, more than 80,000 chemicals are used in everyday items found in American homes, such as furniture. "Of those, only 200 are tested by the Environmental Protection Agency, and only five are regulated," Marcus says.

Stain-resistant fabrics, volatile organic compounds (VOCs) found in lacquers, polyvinyl chloride (PVC) commonly used in outdoor furniture, and antimicrobials found in mattresses all generate toxins during their production. Flame retardants — found in upholstery, foam and mattresses — are increasingly linked to cancer, neurological damage and other serious health problems, according to the National Institutes of Health.

Marcus recommends wool, recycled polyester, and ultrasuede for fabrics, and beeswax and linseed oil for furniture finishes because of their near-zero environmental impact.

5. Don't get overwhelmed

There are so many factors to weigh when measuring an item's sustainability that it can be easy to feel paralyzed. "A piece might be made in Europe, which adds to the impact of shipping, but what if it's made from rapidly renewable materials?" Hodges says. "There's no one clear way to be sustainable."

Just don't shrug your shoulders and give up. "Do as much as you can, and take baby steps," Hodges says. "All of us doing things imperfectly is better than a few people doing it perfectly."