The home Paul Fallman shares with his wife and two daughters has 4,000 square feet of living space. Yet his electric bills have averaged only $180 a month so far this year, despite a cold winter and close-to-record summer highs temperatures.

His natural-gas bill for two tankless water heaters and a fireplace averages $25 a month.

"My focus with this house was energy efficiency," says Fallman, owner of Fallman Design and Construction in Clermont, Fla. "It's so easy to do. It's a great marketing angle. And it's the right thing to do."

The key to the energy efficiency of the lakefront home, which is certified by the Florida Green Building Coalition, is its south-facing orientation, said Fallman, who has made green-building his specialty.

Before starting construction, he commissioned a solar-path study to track the angle of the sun in winter and summer. He used the information to design a home that would be flooded with sunlight during the cooler months, but shaded by porches, balconies and extra-wide roof overhangs when temperatures soar.

"It's the single thing a builder can do to make a home more efficient" without great expense, he says.

The three-garage home is also angled to maximize views across three-kilometre-wide Lake Minnehaha. Facing the lake on the first floor are the kitchen, dining room, living room and master suite, which either open onto screened porches or are shaded by wide roof overhangs and high-performance windows -- tinted, Low-E4 and argon-filled. Upstairs, covered balconies or roof overhangs shade the windows and walls of the three bedrooms and loft area. An apartment above a second garage has similar features.

To receive certification from the green building coalition, a home must be inspected by a green certifier and an energy rater, Fallman says. The green certifier makes as many as 10 checks of the site and home before and during construction, checking for site drainage, well sealed plumbing pipes, doors and windows, and so on. The energy rater conducts a duct-blast test, blower-door test and thermal-envelope test to determine how airtight the home is.

The Fallman home has a Home Energy Rating System (HERS) score of 62 out of 100. The lower the score, the more energy efficient the home. For a home to be Energy Star-rated, it must score 85 or lower.

At present, about 70 per cent of the payback for building green is improved energy-efficiency, Fallman says. Spending $3,000 to $5,000 on equipment upgrades and an additional $2,000 to $3,000 on green construction will pay for itself in 5 to 10 years, he figures.

Certainly, better air-handling equipment cuts down on dust and indoor humidity; better insulation creates a quieter home; drip irrigation in the yard saves water.

The house, which is on the market for $1.1 million, also features these energy-efficient elements:

- Fifty-year shingle roof with Icynene spray-foam insulation, which keeps cool air in, heat and dampness out; protects against dust and insects; and improves structural strength.

- Concrete-block walls with rigid insulation on the first floor, and 2x6 frame with

R-19 batt insulation on the second floor.

- Semi-air conditioned,

200-square-foot attic, which keeps ducts about 30 degrees cooler in summer, cutting cooling costs.

- Low-E4 windows with tinted, high-performance glass and wood frames, which don't conduct heat.

- Non-conductive fiberglass doors with insulated glass.

- Dual-compressor 20 SEER (seasonal energy efficiency ratio) air-conditioner and timeable bathroom fans for humidity control.

- Two tankless gas water heaters.

- Gas fireplace with electric ignition.

- Windows at the top of the stairs to vent rising hot air and ceiling fans in many rooms.

- Energy-Star appliances, which use less energy.