Koehler believes Dow's solar shingles were not successful because they relied on thin-film technology, which is more expensive and less efficient than standard silicon crystalline solar cells.
Traditionally, solar shingles have been more expensive than conventional solar panels, but they're becoming more cost-competitive. Installing solar shingles is more cost effective when replacing your roof, because they can be integrated into your conventional asphalt roof shingles, according to EnergySage, an online solar marketplace.
Similar to Expedia or Kayak, EnergySage is a free online service that allows users to input their information and retrieve standardized quotes for a service -- in this case, the installation of a rooftop solar system. EnergySage generates revenue from fees paid by solar suppliers and is part of a nascent industry that includes other, smaller players such as Geostellar.
In addition to slightly higher costs, solar shingles have been less efficient than traditional solar panels, so homeowners need to cover a larger surface area to get the same amount of electricity.
"That being said, solar shingles can still generate savings on electric bills," EnergySage stated in a blog post.
Solar shingle manufacturer CertainTeed said that its most popular offering -- the Apollo II -- has a solar conversion efficiency of about 14.7%. "Most major panels are higher, and more premium brands like LG, Panasonic and SunPower get up to around 18 to 22%," EnergySage stated.
SunTegra's solar Tile is rated at 67 watts and measures about 1.5 ft. × 4 ft., and it also has an efficiency of up to 14.5%. Each of SunTegra's solar shingles produce up to 100 watts of electricity and are 4-ft x 2-ft in size.
They're installed directly on a roof in an overlapping fashion over standard roofing.
The company's solar tiles are marketed mainly in Colorado, Texas, Florida and the Southwest, and are 13.5 in. wide. Typically 25% of a roof must be covered to product enough energy to warrant a system installation, Koehler said.
SunTegra's solar shingles and tiles are based on the same technology as typical rooftop panels, which Koehler said allows his company's product to be more reliable and readily available through a robust supply chain. Because the SunTegra product is not as ubiquitous as solar panels it still costs from 10% to 20% more for a full rooftop system, Koehler said.
"As we grow in scale, we can eventually have a similar system level price if you add in savings from not having to install a standard roof where the solar shingles or tiles would be," Koehler said.
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