"We've been concerned with the global climate change on some level and issues of sustainability," Silverstone said. "As we started to think about this and what we could do in our lives to minimize climate change and promote good practices, we decided solar power would be a good start."

So in September, Silverstone and Reed had a 3.2-kilowatt photovoltaic system, or solar panels, installed atop their 2,021-square foot home in Cary's Westfield subdivision.

The 16 interlocked panels cover about a third of the south-facing side of the roof and connect directly with the power grid, Silverstone said.

Electricity generated from their solar system is sold to Progress Energy in exchange for credits toward their power bill. Over time, the couple hopes to reap the benefits of lower monthly expenses.

The solar installation was just the first in a series of green initiatives the couple hope will help them to not only lessen their carbon footprint but also reduce their monthly electric bill. Silverstone and Reed participated in an energy audit several weeks ago to find ways to increase efficiency. "We're still considering solar hot water," Silverstone added.

The Cary couple are among many who have started their own green revolution.

The number of homeowners and businesses interested in renewable energy technologies has increased significantly since the 1970s.

"We've seen tremendous change in the last several years as the green economy has grown and expanded," said Julie Robinson, marketing director for the N.C. Sustainable Energy Association.

The number of green firms in the Tar Heel state more than tripled to 530 in 2009, according to the most recent N.C. Renewable Energy & Energy Efficiency Industries Census, an annual report published by the association.

The organization is aiding the cause with its annual Wake Green Building and Solar Tour, held each October, to showcase local homes and businesses that feature green products or have undergone environmentally-friendly renovations.

This year's tour had five stops in Cary, including renovations by companies such as Yes! Solar Systems of Cary and sister company Code Green Renovations and Construction. The tour also included a stop at a McDonald's on Kildaire Farm Road that was built seeking certification from the U.S. Green Building Council.

"This year, statewide, we had over 1,000 attend green tours, which is consistent with the last few years," said Ivan Urlaub, director of NCSEA.

Elsewhere in North Carolina, NCSEA conducts green tours in Durham, Greenville and Henderson County, among other counties and municipalities. Urlaub said the Southern Home Show and local homebuilders associations have also begun hosting similar events throughout the year.

In Cary, as in other towns across North Carolina, more homeowners and entrepreneurs are pushing forward on renewable energy. Robinson said the nation's economic downturn has played a role in that transition.

"From the energy-efficiency side of things, everyone's pocketbooks have suffered in the past year," she said. "People are looking to stretch their money a little farther."

And some are succeeding, despite the upfront costs associated with many energy efficiency projects. A photovoltaic system, for example, can cost tens of thousands of dollars.

Urlaub said businesses and homeowners make it work by starting small. Urlaub said he and his wife had a programmable thermostat installed in their Durham home in October, a simple move that saved them 33 percent on their natural gas bill when compared to the same month in 2008.

"It's like building blocks," Urlaub said. "With each improvement made, there's the potential for greater savings. And especially in a business situation, what they realize in savings they can invest in bigger and bigger capital costs to make bigger and bigger reductions in their energy use."

Urlaub said a business or homeowner might invest in technology such as a solar hot water system. Although the systems can cost several thousand dollars, they produce quick returns, Urlaub added.

"In a recession, by putting cash into solar hot water, we've found that it can actually yield a better return on the investment than putting money in a money-market account or other low-risk investment options," he said.

Steve Sedahl is one of two Cary homeowners whose homes were featured in this fall's Wake Green Building and Solar Tour. He and his wife Janeen Sullivan had a number of green devices, including energy-efficient windows and Energy Star appliances, added in 2008 during an extensive remodeling of the couple's 108-year-old cottage on West Chatham Street.

The couple has experienced savings on their monthly electric bill since they had a solar hot water heater installed during the summer. "As far as dollars and cents go, there's an easy way to show that," Sedahl said.

In October 2008, Sedahl and Sullivan spent $155.01 on their power bill.

Last month, the couple's bill had shrunk to $98.70, a savings of nearly 37 percent.

"The savings are real," Sedahl said. "It's just amazing."