MOUNTAIN HOME, Texas -- Using green technology and sustainable materials, Rick and Stephanie Ertel built their Hill Country home to be totally independent of utilities.

Solar panels and a series of batteries draw and store enough energy to power the home. Meters track the power production and consumption, ensuring that there's never a power shortage.

"We have 32 marina batteries in that closet and those batteries can store five days of power for us," says Rick Ertel.

An inverter changes the batteries' direct current power to an alternating current like in most households.

The couple has had no need for public water lines.

After recent heavy rainfall, the couple's 20,000 gallon tank is overflowing with water.

Water in their home is heated through a solar water heating system and windows are modern, designed to let in light but keep out heat.

A modern ceramic cook top, powered by firewood, is used to cook food.

The home's large columns, made of mountain cedar, allow heat to rise and vent from the home.

"It's designed so during the wintertime, the sun comes in all of these windows and will heat up the mass of the house," Rick Ertel said.

The walls of the home were built over a foot thick to provide insulation better than r50 specification.

The Ertels said even without air conditioning or a furnace, their home never reached temperatures above 84 degrees during the summer or below 68 degrees over the winter.