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University of California at Berkeley professor Karina Garbesi suns herself beside her solar panel collectors atop the roof of her home Kensington, Calif.

Home solar: What kind of system should you buy?

By THE EDITORS OF E MAGAZINE  |  September 12, 2008 edition

Q: I am considering solar panels for my roof to provide heat for my hot water and possibly to do more than that. Are some kinds of solar panels better than others? How do I find a knowledgeable installer?
– Elise, Watertown, Mass.

A:
The type of solar energy capture system you put on your home depends on your needs. If you want to go full tilt and generate usable electricity from your home’s rooftop – and even possibly contribute power back to the larger grid – tried-and-true photovoltaic arrays might be just the ticket. A typical installation involves the panels, which are constructed of many individual silicon-based photovoltaic cells and their support structures, along with an inverter, electrical conduit piping, and AC/DC disconnect switches.

These systems can cost tens of thousands of dollars to install, and as such may not pencil out for those looking for the cheapest power solution. But the upside is that homeowners with photovoltaic panels on their rooftops can rest assured that as long as the sun shines, they will have power to spare without generating carbon dioxide and other noxious pollutants.

Qualified solar installers can usually advise clients on which types of systems will work best given the specific location of a home. US homeowners can find qualified photovoltaic installers via the website FindSolar.com. And the North American Board of Certified Energy Practitioners (NABCEP) provides a free searchable database of its US and Canadian members specializing in home solar setups.

For less demanding applications, such as heating water for your home or swimming pool, a much simpler (and less expensive) solar thermal system might be all you need. A basic hot water system usually consists of a solar collector – basically a small metal box with a glass or plastic cover and a black copper or aluminum absorber plate inside – tied into the building’s plumbing and electrical works. According to the industry tracker website Solarbuzz, such solar collectors are usually mounted on rooftops.

Professional installers can get your home up and running with a solar thermal system for less than $4,000 in most cases. While the savings in your electric bill may be small, homeowners in it for the long haul will definitely save over time, all the while enjoying the fact that they have shrunk their household’s carbon footprint significantly.

Homeowners looking to find out more about residential solar systems should check out the RealGoods Solar Living Sourcebook, a 600-plus page renewable-energy bible now in its 30th edition. The book features the latest nuts-and-bolts information on how to harvest renewable energy in a variety of ways, depending on need. RealGoods sells much, if not all, of the equipment needed.

Another reason to consider going solar in one fashion or another is tax incentives. According to the Database of State Incentives for Renewables and Efficiency, 17 states now offer homeowners some kind of tax rebate or incentive for the purchase or installation (or both) of solar power equipment. You can see what your state offers by logging on to the
dsireusa.org website, where the searchable database is available in its entirety free of charge.

Got an environmental question? Write: EarthTalk, c/o E – The Environmental Magazine, Box 5098, Westport, CT 06881. Or e-mail: earthtalk@emagazine.com.

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Comments

1. Esther McElfish | 09.12.08

Good job in getting the word out about tax incentives and rebates! Those of us who have been trying to get the word out about renewable energy sources for over 20 years realized a long time ago that people will really start changing their habits when it hits their pocketbook, as it is doing now!
Tax rebates and incentives do make a difference! Check out NY Times Journalist Thomas L Friedman’s new book, “Hot, Flat & Crowded” and his recommendations for a Green Revolution (& his push for these kinds of incentives)

2. Marko | 09.13.08

The answer is none. The beginning of life efficiency for those solar cells might start off at 15% but in 3 years, its down to 5% due to degradation. That makes your return on investment zero. Your $80,000 system would need to be replaced in 5-7 years to sustain the proper efficiency to keep your electrical bills in check. The efficiency of solar cells must be improved to over 35% and the resistance to radiation must be improved to make solar energy viable.

3. Shannon | 09.16.08

Marko disinforms irresponsibly. Standard PV modules warranty 80% of rated efficiency for 25 years.

Find a reasonable estimate for your payback time at
http://www.findsolar.com/index.php?page=rightforme

The site also includes local incentive information in its estimates.

4. Cailyn Koch | 10.07.08

Solar panels is very competitive. If you know what youre doing, it can be solar panels in your winning strategy. However, you must follow the following rules: Renewables and Efficiency: You need a very strong hand.

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