You might have noticed lots of buzz this past week about Michigan-based manufacturer Dow Chemical Company’s new line of solar shingles . DOWPOWERHOUSE shingles are made of CIGS or thin film photovoltaics. Theshingles are designed to be installed like regular shingles–and byregular roofers, which is what sets them apart from shingles currentlyon the market. Now, Dow has not made a lot of technical specs availableabout these shingles, and we at GetSolar can’t seem to get answers tosome of our questions directly from them. A couple sources say theyoperate at about 10 percent efficiency (which is fairly standard forshingles; normal solar panels are more like 16 to 20 percent, thoughsome lab tests have gone as high as about 30 percent). So, we can’tdiscuss these particular shingles in depth. What we can do is tell yousome of the pros and cons of solar shingles in general.
- Easy to install. Even with normal solar shingles,which do require professional solar installers’ attention at somestage, some of the work can be done by regular roofers.
- Can be cheaper than normal solar panels. This istrue pretty much only when you’re replacing your roof anyhow, and theslightly higher cost of solar shingles is then offset by what you’resaving in traditional roofing materials.
- Appealing aesthetics. Many people prefer theintegrated look of solar shingles to normal solar panels. The surfaceis still much like the dark blue, shiny surface of regular panels, butsince they’re the same size and shape and height as your othershingles, they blend much better. People with strict HOAs or inhistoric districts find solar shingles appealing for this reason. Formy part, I actually love how normal solar panels look, and if you’remaking the investment in solar, isn’t it nice to get a little greenstreet cred by getting noticed?
- Less efficient. With most solar panels, you caninstall about 1 kw of energy generating capacity on 100 square feet ofroof surface. With solar shingles, you need 30-50 percent moreinstallation area, depending on the site in question as well as on theparticular shingles and panels you’re comparing. Efficiency can befurther reduced by angle: with regular solar panels, installers canadjust their angle of exposure to the sun to maximize insolation (fancyword for how much sun actually hits the panels and is transmuted intoelectricity). This means that you need more product to achieve the sameoutput, so you’re spending more per watt. Which leads us to…
- Usually more expensive. Due to the efficiencylosses, most homeowners would see more expensive project quotes withsolar shingles than with normal silicon solar panels.
- Fewer installers work with them. It can bechallenging to find professional solar installers who will give you aquote for solar shingles. Partly this is because the shingles requiredifferent training, which not all installers pursue, and partly becausedue to their lower efficiency, it can be harder for installers topresent a quote that will get you a good return on your investment.
Dow’s new product won’t come to market until at least 2010 andpossibly later, and until production catches up with demand, thesesolar shingles may be hard to get your hands on. Low efficiency solarshingles that cut solar installers out of the picture aren’t exactly arecipe for industry success, either; so while it’s a great technologybreakthrough, until we know more about it, we’re reserving judgment.And hey, if you’re interested in going solar? We’ve said it before and we’ll say it again: waiting for new technology to come out and for prices to drop is not always the wisest path.