You probably only have to look at the huge solar panels in the front yard to get an idea that Nate and Etta Kantor like to save energy.

But it's the little things about the way the house is built -- things you don't see -- that make it use almost no energy.

In fact, the Kantor's didn't even have an electric bill last year.

It's that lack of energy use that won the New Canaan couple a $5,000 prize in a contest sponsored by several Connecticut utility companies. The first annual Zero Energy Challenge sought to find the house in Connecticut that was essentially built so energy efficient that it used as close to no energy as possible.

"I was concerned about what kind of planet we are leaving our children," said Etta Kantor during a tour of their Trinity Pass Road home. "I was tired of complaining so I decided to do something about it."

To first look at the Adirondack-style home, it looks like a cabin that you might find in the woods of Vermont, which is exactly the look Kantor said she was going for. But take a closer look, and you'll see how the house was built to be sustainable, with energy-conserving features, recycled materials, and an envelope that keeps the inside of the house at a draft-free 60 degrees with no heat on, even when it's 20 degrees outside.

"Their whole goal was to educate other people on how to be green," said Chris Trolle, partner at Wilton-based BPC Green Builders, the firm contracted to build the house. The Kantor's moved in last December. "Every thing we build is high-performance and high-efficiency."

Before the 5,000-square-foot house was even built, the property was designed with efficiency in mind. There is no asphalt -- the driveway is made from a permeable surface of gravel that allows rainwater to seep into the ground. A channel-like drainage ditch called a "bioswale" carries drainage water around the home into a rain garden in the back yard.

The wood used to build the house is taken from hemlocks grown in managed forests -- when trees are cut down others are planted. The studs of the house are placed farther apart than standard houses, and sprayed with insulation that lets very little heat out.

"We don't get any drafts in this house at all," Kantor said.

The kitchen counters are made from 100 percent recycled glass mixed in with concrete, a process that gives the feel and look of granite or marble. The roofing tiles look like black slate, but are actually made from recycled rubber. Rain water off the roof is directed onto one of six "rain chains," which run into underground cisterns to collect water to be reused for irrigation purposes.

"We let nature be the model of how to be in the world," Kantor said. "There is no waste in nature. We humans are screwing the earth up and the only way to fix it is to follow nature."

The house is powered by three large solar panels in the front of the house that are pointed at the sun, and generate more energy than the house needs on any given day. In fact, Kantor said last year they only had to pay a $16 fee to be connected to the electrical grid. Whatever electricity is not used gets sold, she said.

"Most of the time they end up owing us money," she said.

In the basement of the house, there is a 957-gallon solar-heated water tank, and a tank that collects gray water from the sinks, showers, and washing machine to be reused. A compost toilet uses a tank with bacteria that breaks down human waste to be reused for fertilizer.

Kantor has a long history of living a green life. An environmental activist by trade and a former 30-year Westport resident, she made headlines when she retrofitted her Volkswagen to run on used vegetable oil from Chinese Restaurants. When she and her husband Nate, a former telecommunications executive, decided to move to New Canaan, she wanted to build a sustainable home.

"My husband doesn't agree with everything but he went along with it," she said. "A lot of what we call waste isn't. We don't have to keep stressing the planet by taking all the resources."

Kantor is extreme when it comes to living green, and she admits that not everyone will go as far as having a compostable toilet. She said she believes that everyone can make little changes to their house that can be healthier for themselves as well as the environment. She wouldn't divulge the cost of her house, but she said people would be shocked to find the cost comparable to similar houses in the area.

"Sustainability does not have be expensive," she said. "It intimidates people because they think they can't afford this. Any house can be made sustainable."