Manufacturers and retailers looking to cash in on the green movement are rolling out green home building and remodeling products and demand is helping to drive down costs, experts say.

LOS ANGELES — Robert Mechielsen's designs for environmentally friendly homes often include cutting edge features such as high-efficiency heating and cooling systems and solar panels to convert sunshine into electricity.

But he's only half joking when he says many of the best green home solutions available to homeowners hail from the 18th century, such as installing awnings to keep a home cooler.

"There's also a very advanced way of using wind technology — it's drying your clothes outside," quips Mechielsen, founder of Studio RMA in Los Angeles.

With environmental consciousness at an all-time high, homeowners searching for Earth-friendly ideas don't have to settle for such rustic measures. Manufacturers and retailers looking to cash in on the green movement are rolling out green home building and remodeling products and demand is helping to drive down costs, experts say.

Market research by McGraw-Hill Construction earlier this year projects the residential green building market will have annual sales between $12 billion and $20 billion this year. That would represent between 6 percent and 10 percent, respectively, of the overall homebuilding market.

The firm has said it expects the green building market will double by 2012.

Some of the products are based on new technology, but many are based on concepts that have been kicking around for decades with relatively few takers, such as solar water heaters.

That's changing, thanks in part to soaring energy costs.

Good thing homeowners have more options than ever — without resorting to hanging their laundry out to dry.

"It's a very dynamic time. In 10 years, there's not going to be such a thing as green building, just building," said Sarah Beatty, founder of Green Depot, New York-based Green Depot, a chain of stores in the Northeast that sells green home building products.

At the top of the list for Mechielsen is installing a souped-up version of an attic ventilator, such as the NightBreeze by David Energy Group, which electronically manages how evening air circulates into the home, lowering cooling costs.

"It works on a computer, so people don't have to open or close their windows, which is so 18th century," said Mechielsen, who counts commercial and residential projects, such as the EcoHouse in Pasadena, Calif., among his green building efforts. "It's really a big cost-saver."

Mechielsen also raves about a relatively new generation of solar panel technology known as thin-film solar. Instead of being made of costly silicon, thin-film solar cells are made of copper, indium, gallium and selenide. The cells are thinner and more flexible than existing photovoltaic technology.

"It doesn't look as clunky," Mechielsen says.

Applications for residential use are expected to become available as early as next year, experts say.

Sometimes the most efficient energy reductions don't come through technological wizardry. Up to 25 percent of heating and cooling costs are the result of heat loss, as air moves in and out of a house through holes, improperly sealed windows and insufficient insulation.

"If you're looking at a home as a system you can start to address low-hanging fruit that aren't the sexy solar panels on the roof, but are things like tightening up the house," suggests David Johnston, co-author of "Green From The Ground Up."

One product increasingly being used in residential building and renovation projects is closed cell polyurethane foam insulation, which is sprayed between walls or in the attic and expands to cover small cracks and other openings through which heat can escape.

Traditional insulation products can be inefficient or harmful to the environment. Other green options include insulation sprays made of denim or Cel-Pak, which is made of recycled newspapers.

"It's the first and most cost-effective thing (homeowners) can do," Johnston said. "Most people don't even know they can do that, they just want to put more pink stuff in the attic."

Another no-brainer is replacing incandescent light bulbs with more energy efficient options. LEDs, or light-emmitting diodes, remain the latest in efficient home lighting technology, but many environmental experts continue to favor compact-flourescent lights as a better alternative, saying the LEDs remain too expensive by comparison.

Another criticism is there aren't many options in terms of light fixtures that work with LEDs. Johnston says that's beginning to change and he expects prices on LEDs to fall dramatically as a result.

Another option for lighting is designed to bring in more natural light without having to go through the expense of building a full skylight.

Solatube International Inc. of Vista, Calif., offers a dome-shaped product that installs on the roof and uses reflectors to bend light up to 90 degrees into the house.

"It literally pushes light into an interior space," Beatty said. "It looks like you're looking outside at the sky."

Shaun Parvez badly wanted to include a solar energy-powered system or a wind power generator as part of the extensive expansion and remodel of his home in Washington Township, N.J., about 15 miles outside New York City.

But the structure, which is going from a one-story, 2,800 square-foot ranch house into a 2 1/2-story, 10,000 square-foot home, is blanketed with shade from 100-year-old oak trees.

One of the many green-friendly options he chose to is a smart sprinkler system to help conserve water use. Such systems were traditionally used to manage water use in commercial properties, such as golf courses and nurseries. Now, manufacturers have been tailoring them for green-conscious homeowners.

"It constantly measures rainfall to see if it had rained throughout the night ... if it had rained, there's no reason to run the sprinklers, said Parvez.

Jay Hall, a technical consultant for the U.S. Green Building Council, says homeowners looking to amp up their green credentials should be wary of spending thousands of dollars on high-end products before they first consider cheaper upgrades, beginning with buying Energy Star-rated appliances, which can save up to 30 percent off electricity costs.

Still, some products, including solar water heaters, are a great option, Hall says.

Solar water heaters were first invented in the 1970s and 1980s, but are now becoming more widely available and more efficient.

One type, an evacuated tube solar water heater, uses glass cylinders to collect solar energy and heat a small copper pipe inside, which transfers heat to a manifold filled with water. It helps offset the use of a standard water heater.

The Rev. Gordon Polenz acquired one for his home in Sidney, a small town about 95 miles south of Syracuse, N.Y., hoping it will help lower his electric bill.

"Up to now, if you're just going to talk financially, it wasn't worth it," Polenz said, noting that seeing the cost of home heating oil jump $1 a gallon helped change his mind.

The 40-gallon unit by Silicon Solar Inc. cost Polenz $1,000, plus another $2,000 to install, because he opted to have some concrete slab laid down to secure the unit.

Polenz hopes to make his money back in savings within four years. If gas prices continue to go up, the payback will be a lot sooner.