Marilyn Ross Adams never has to worry about a cold shower again.

The Angie’s List member hired highly rated Solar Service Inc., to install a solar thermal system at her Glenview, Ill., home in February 2010.

“At my old house, I had a 40-gallon gas-fi red water heater and toward the end of a shower, I’d run out of hot water,” she says. “After the solar went in, I never ran out.”

Ross Adams’ solar array consists of seven rooftop panels on her 5,500-square-foot-house and two hot water tanks, which cost around $15,000 after state and federal tax rebates and incentives. Her solarthermal system turns solar energy into heat, which can be used to warm both water and air.

That differs from a photovoltaic system, which converts sunlight directly into electricity. She estimates 80 percent of the hot water and 30 percent of the home’s heat are fueled by solar energy. “I wish more people would take an interest in solar,” she says. “I’m planning on getting some electric panels as well.”

Angie’s List member-submitted reports on solar panel installs more than tripled in the past three years, and 30 percent of members who took a recent online poll say they’re considering solar panels. These numbers are trending alongside national statistics.

The Solar Energy Industries Association says the residential photovoltaic market grew 68 percent in 2010 and 21 percent from the second to third quarter in 2011, according to the latest numbers at press time. The photovoltaic market continues to be the largest component of solar market growth in the country as prices continue to drop.

California leads the way with 44 percent of all photovoltaic installations, followed by New Jersey, New Mexico, Arizona, Pennsylvania, North Carolina and Colorado. The number of residential solar thermal systems also has grown every year since 2004, with installations increasing 5 percent in 2010 from 2009.

Is solar energy the right choice for your home? Curious how much a solar panel system will cost in your neck of the woods? Check out the solar calculator at findsolar.com for a rough estimate including any federal or local incentives/rebates. For a list of state-by-state available tax incentives and rebates, visit the Database of State Incentives for Renewables & Efficiency at dsireusa.org.

“As solar [system] prices come down and utility costs rise, homeowners are figuring out that it makes sense,” says Seth Masia, spokesman for the American Solar Energy Society, a nonprofit established in 1954 and comprised of more than 8,000 solar professionals. “The payback period can be seven to 15 years, but where electricity is expensive, it makes sense.”

However, Brandon Leavitt, founder of the Niles, Ill.-based Solar Service Inc. says there’s a lot of misinformation out there about solar systems. “People are skeptical that it won’t work if they live in the North or that it’s just for millionaires,” he says. “But solar energy falls on your property, no matter where you live.”

The cost of installing a solar thermal or a photovoltaic system varies nationwide. Photovoltaic prices are determined by watts, with the national installed pricing averaging at $6.24 per watt, according to SEIA.

How many watts, and therefore solar panels, a homeowner needs depends on their energy consumption and solar insolation — how many hours of daylight you receive. In general, a solar photovoltaic system between 1 and 5 kilowatts is sufficient to meet the electricity needs of most homes and average between $6,240 and $31,200 before incentives or rebates.

In 43 states, homeowners with solar photovoltaic systems have the opportunity to sell back extra energy to their local utility companies. Called net metering, it’s an agreement that credits customers for excess solar energy sent back to the grid from their house.

Similarly to photovoltaic systems, the price of a solar thermal system depends on the lifestyle of those living in the house. Leavitt says an average family of four would need a two-panel system for their daily hot water needs, given that system receives four hours of sun, seven out of 10 days.

“In Illinois, a two-panel system could cost between $10,000 and $12,000, but after incentives the cost would drop to $4,000 to $6,000,” he says, noting the price and incentives would double if you included heat in the system. “It doesn’t replace the hot water heater or the furnace, just the energy that appliance uses,” he says.

The number of panels needed will also depend on where you live. In states with warm climates and better exposure to the sun, a smaller solar thermal system will produce the same amount of energy as a larger system in a northern state.

When it comes to deciding if a solar thermal or photovoltaic system will give you more value for your money, geography — and whether you use your A/C or furnace more often — plays a big part.

“In the Southwest, electricity is expensive and you’re running your A/C more often,” Masia says. “But if you’re in a state like Kentucky or Tennessee, coal states that have low electric rates, it might not make financial sense [to install photovoltaic].”

Federal and state rebates continue to be a major selling point, including a 30 percent federal tax credit for installed photovoltaic and solar thermal systems that expires at the end of 2016. Forty-three states offerfinancial incentives for photovoltaic installations and 38 states for solar thermal, including cash rebates, tax credits and incentives from local utility companies.

“The federal tax credit is the best credit that’s out there,” says Jerry Hughes, owner of highly rated Stellar Roofing and Solar in Golden, Colo.

Extended manufacturer guarantees and the virtual lack of maintenance on solar panels is also an asset. “The panels are warranted for 20 to 25 years,” Hughes says. Because solar panels last so long, the roof should be in top condition. If the roof only has five years left, it should be replaced before solarpanel installation.

“We design the panels to be maintenance-free and in general we want them to be left alone,” says Russ Patzer, owner of highly rated Sun Valley Solar Solutions in Chandler, Ariz. When it comes time for a new roof, there are options.

Most customers only have to re-roof around the solar system because everything under it stays in like-new condition,” Patzer says. “If a whole re-roof is needed, we can remove the panels.”

With increased interest in solar energy, the industry is witnessing an influx of new businesses. To make certain you’re dealing with a reputable company, JC Shore, CEO of highly rated Circular Energy in Austin, Texas, says to review reports on Angie’s List.

“Try to find a company with big ears and little mouth — someone who’s going to listen,” he says.

While licensing requirements vary in each state, industry experts recommend also checking if a provider is accredited with the North American Board of Certified Energy Practitioners.They must pass an exam and agree to follow a code of ethics.

“Sometimes banks that finance solar systems and some states that offer rebates require you to work with a NABCEP vendor,” Masia says. In addition, homeowners should verify a licensed electrician is responsible for connecting a photovoltaic system to the electrical grid.

Shore says homeowners need to go through an assessment and talk to others in the area who have solar. “For some it’s political, some say it’s financial – they all have a different yardstick to measure whether solar makes sense,” he says.

Member Wendell Kellum of Philadelphia says he wanted to reduce his carbon footprint and improve his home’s energy efficiency, so he hired highly rated Mercury Solar Systems to install a photovoltaic system.

“It’s working great,” he says. “The panels produce about 75 percent of the power we use over the course of a year. It’s made us pay attention to our overall usage and we try to cut down.”

For Ross Adams, the decision also came down to protecting the environment. “The pollution from fossil fuels made me well aware that we need alternatives,” she says. “And I realized that solar was one of the answers.”