High-Impact Savings

As it turns out, it's a lot more than chump change.

"We lived from paycheck to paycheck before, and had no savings," Beavan says. "Now we live on one salary, and save the other. One of the things we noticed was how much money was flowing out on things that weren't good for us, and that we didn't care about."

Among the biggest offenders: recreational shopping and restaurants. "We used to wake up, get on the phone and call Bagel Bob's, and they'd come over with breakfast. Then we would go to work and get takeout for lunch," Beavan recalls. "Then we would be in a big rush to come home, turn on the TV, and say, 'What do you want -- Indian, Thai, Italian?' We'd Google it with our ZIP code and find a restaurant. It was an ecological, health, and financial disaster."

Travel expenses, which used to include three or four flights a year, are gone. They ride bikes and scooters to work and recreation. (A recent bike trip to the beach took two and a half hours.) They've zapped utilities -- Beavan's laptop is powered by a solar energy panel -- and only use the oven to bake homemade bread. The family received a $400 rebate from Con Edison when it finally read their meter after several months of estimated bills.

Tradeoffs and Unanticipated Boons

A few items in the no-impact life, though, are pricey: The family spends $30 a week for a pound and a half of artisanal, unpasteurized cheese made from the milk of grass-fed cows. Eggs are $7 a dozen from pasture-raised hens. And it takes a lot more time to accomplish ordinary chores, such as laundry, which they do by hand.

But aside from the mortgage and a few other regular bills, household expenses are down to $120 a week, Beavan estimates. He rarely carries money anymore, unless he's buying food. The family now tithes 10 percent of its income to charities, including Doctors Without Borders and Save the Children. Meanwhile, all of that walking, biking, and scootering has been a health boon: Beavan lost 15 pounds, his wife lost 10.

Beavan is no scold, denouncing greenhouse-gas-spewing Hummer drivers and McMansion owners from his no-impact ivory tower. Instead, his blog is by turns philosophical and hilarious, documenting attempts to wash clothing in the bathtub (picture grape-stompers at harvest time); his wife's reaction to the worms he brought home for composting; and the time he accidentally ran over his Treo 650 with his bicycle (which he couldn't replace because of the no-new-purchases rule).

"I might as well have been looking at a dead body in the middle of the road," he writes of the cell phone. "If I had had a brown paper bag with me, I would have hyperventilated in it."

Tips for Treading More Lightly

While Beavan is unlikely to inspire copycats willing to give up their refrigerators, his experiment is inspiration for people looking to save money and tread more lightly on the planet.

Here are a few ideas:

• Switch to compact fluorescent light bulbs. (You may not have a choice soon anyway.) They save at least $30 in electricity costs over each bulb's lifetime, according to the Energy Department.

If every U.S. home replaced just one bulb with an "Energy Star" qualified alternative, it would conserve enough power to light more than 3 million homes for a year and prevent greenhouse gases equal to the emissions of 800,000 cars.

• Household appliances account for 15 percent of each American's greenhouse gas emissions, Beavan says. Unplug them when not in use.

Televisions, computer equipment, and anything else plugged into the wall will drain energy even when turned off. One study estimates consumers can save from 6 to 26 percent of their electricity bill by eliminating so-called "standby loss."

Also, buy an energy-saving power strip designed to ensure no electricity is used ($30 at Ace Hardware), or use a standard power strip and pull the cord when items aren't in use.

• Track your water leaks: An estimated 16 percent of your bill goes down the drain this way. Check out this document to learn how to detect a leak.

• Take a weeklong vacation during the year instead of three weekend getaways. "A lot of us have this habit of the weekend getaway, and flying has a huge impact," Beavan says. "It's the same amount of vacation time, but you could reduce your carbon impact by one-third and probably reduce your cost by one-third."

When you do travel, consider a lower-impact form of transportation, such as the train. For local trips, use a bicycle.

• Eliminate your junk mail. Every year, 100 million trees' worth of direct mail is sent to U.S. homes, and 5.8 million tons of it ends up in municipal dumps, according to environmental advocacy group the Center for a New American Dream.

The production and destruction of direct mail consumes more energy than 3 million cars -- and let's face it, those Pottery Barn sale catalogs can be mighty tempting. Go online to junk your junk mail.

• Buy produce, dairy, and meat that originates within 250 miles of your hometown to reduce air pollution related to transportation. The food is fresher, lasts longer, and tastes better (as I discovered when visiting my local greenmarket this summer).

• Be second-hand savvy. Look to craigslist, eBay, Freecycle, Freegan.info, and flea markets for creative treasures.

"We went to the flea market the other day and got a $1,200 Art Deco kitchen table for $150," says Beavan. "You can get really expensive stuff for normal cost, or normal-cost stuff for really cheap."

Sustainable Rewards

Although Beavan wouldn't necessarily call his experiment in no-impact living enjoyable -- "doing laundry by hand is a pain in the butt," he says -- life is more satisfying. When Isabella gets out of preschool, they hop on Beavan's three-wheeled rickshaw bicycle and tool around town or head over to the river.

"We call it 'seeing what happens' -- riding around and looking for adventures," he says. "We're so much more engaged in our lives. Things move slower. We spend more time talking to each other, reading, eating together, seeing friends, and going to the park. It's fun to go to the farmer's market and joke with people whose names I know -- a lot more fun than going to the grocery store."