EMIGRANT, Mont. - Pouwel Gelderloos' house in Emigrant is eco-friendly, but you're not going to find straw bales in the walls or composting toilets. Solar panels and a small wind machine whirling in the front yard are the only obvious signs that this house is something different.

A closer look reveals a house that works with everything in nature.

The sun, the wind, the rain and snow and even the earth all heat, cool or hydrate the house in one way or another.

"Instead of just shelter, we can design a house to harvest the elements," Gelderloos said.

The result is a home in harmony with its environment without sacrificing the comforts of a modern lifestyle.

Gelderloos calls his house a "hybrid" house.

"We're completely off the grid, but we're tied to it," he said. The house is designed to operate independently but switch seamlessly to conventional electricity, propane gas and a well if needed.

"We wanted to do something that has curb appeal," he said.

As builders worked on the finishing touches, Gelderloos gave visitors a tour of the house he designed, built and lives in with his wife and three children.

The 3,000-square-foot structure is octagon-shaped with wings and is powered by a passive solar system and a wind generator. The house has a basement, main floor and upper floor and includes three bedrooms, two and a half bathrooms, a dining room, laundry room and kitchen.

Gelderloos designed the south-facing house so it catches the sun's rays as it moves across the sky. The north side is well insulated.

Solar panels and a wind machine generate up to 7 kilowatts of electricity, which is stored in a bank of batteries in the basement. Conventional power from the grid charges the batteries only when needed. The system generates more power than is needed for daily use, Gelderloos said.

An atrium that wraps around the front of the house helps store the heat in rock, sand, brick and concrete floors. Two large doors, which open into the atrium from the living room, allow Gelderloos to let warm air flow into the living areas or to keep the house cool on hot days. The atrium also doubles as a greenhouse, allowing Gelderloos and his family to grow plants and vegetables all year. Recycled "gray water" irrigates the plants and is filtered before being used to flush toilets.

A super-insulated roof, 14-inch-thick double exterior walls filled with insulation and energy-efficient windows also help heat and cool the house. There is an additional two-inch layer of insulation on the exterior of the house.

When temperatures fell below zero last winter, the house stayed at 70 degrees, he said.

In the cathedral-style living room is a tall wood fireplace designed to disperse heat throughout the house.

The house is cooled by a system that circulates air past underground rainwater collection tanks.

For water, the house uses rain and snow collected from the roof by large gutters. Gravel in the gutters filters out leaves and other debris before the precipitation flows through downspouts to a series of underground tanks that hold 10,000 gallons. The water is filtered again to remove microbes.

Gelderloos uses another solar collector on the roof for his hot water system, which is backed up by a 98 percent efficient boiler.

"So far, I've wanted to conserve water more than anything," Gelderloos said.

The house has energy-efficient appliances, on-demand hot water at the fixtures and double-flush toilets that use different amounts of water depending on whether flushing solid or liquid wastes.

For all the energy conserved, Gelderloos doesn't consider himself a hard-core environmentalist.

"I'm not exactly a tree hugger," he said. Designing and building the hybrid house is "completely out of the box for me," he added.

So what motivated him?

"It's a really egotistical, non-spectacular reason," he said. "I was tired of doing everything the same old way. I wanted to do something different. I wanted to create an adventure for myself. "

A native of Holland, Gelderloos, 59, immigrated to the United States 28 years ago and has lived in Emigrant for 26 years. In Amsterdam, Gelderloos owned a remodeling and restoration business and got into construction after a neighbor admired the remodeling he did on his own bathroom. But Gelderloos found Amsterdam's rules and regulations stifling. "They want to keep everything exactly the same," he said.

In America, Gelderloos found more freedom and "so much space," he said.

Gelderloos spent six years researching alternative systems and designing his hybrid house before breaking ground in March 2007. He said his hybrid house cost about $400,000, and he figures it was about 30 percent more expensive to build than a house with conventional systems. A hybrid house could be built for less, depending on what an owner wanted, he said.