Posted by Cris Carl | Aug 18, 2010

Solar Roof Shingles

Although not available for retrofitting, these are a great solar system for new homes.

SunPower Solar ShinglesSolar roof shingles are gaining ground for residential use, but are a ways off for the do-it-yourselfer. “Our goal is ease of installation. But its one step at a time right now,” said David Fox, corporate officer for Nature’s Energy Solutions LLC, based in Raleigh, North Carolina. “If you have a lot of building knowledge, you might be able to do it,” said Fox, though in general, he doesn’t recommend it.

Many companies, such as SunPower Corporation, based in California, have been working on numerous housing and commercial developments, but do not sell solar shingles directly to consumers yet. An online search may bring up companies that will sell solar shingles, claiming that most roofers could install them, but beware of such claims.

What are solar shingles?

 Also known as Building-Integrated Photovoltaics, solar shingles are strips of smaller solar panels designed to have the appearance of roofing material such as asphalt or slate. Solar shingles are incorporated into the roofing material for the generation of solar electrical power. Like standard solar panels, you will save on electric bills in an environmentally-friendly way. Solar shingles have been noted to be more efficient than standard solar panels. “All the (electrical) contacts are on the back (of solar shingles). That’s a major part of what creates better efficiency – the way the electrons and protons work together. They have a smaller space to move around in,” said Helen Kendrick, corporate communications manager for SunPower.

Solar shingles can be nailed into place and are flexible, assuming the pattern of the roofing material. Solar shingles have electrical lead wires that extend 12 inches from the underside of each shingle, passing through the roof deck. The lead wires are then attached to a converter and connections within the home. The sun’s warmth helps to bind the shingles together creating a weather-tight seal. Most solar shingles are rated to withstand an 80 mph wind load. Systems generally last 20 to 25 years and require no back ventilation.

If you are building a new home:

Most systems are installed on new building projects, as many companies, including SunPower, do not retro-fit. SunPower's SunTile is available to commercial developers building new home communities.  “Our product looks like a skylight. They integrate very nicely,” said Kendrick.  Fox and Kendrick agree that for the time being, unless you are highly skilled, solar shingles should only be installed by professionals. “Our dealers go through a rigorous training,” said Kendrick.  SunPower SunTile can only be installed by SunPower. 

Fox explained that one of the main reasons solar shingles should be installed by professionals is safety. He gave the example of a hurricane striking and knocking out power in a community. If your home’s solar shingles are undamaged and are continuing to generate electricity, a utility worker doing repairs on the line could be injured if the system wasn’t installed properly with emergency shut-offs. Fox explained that solar shingles have an inverter on the roof that changes the electricity from DC to AC and that their system has “two or three stop-gaps for emergency shut-off.”

SunPower has a variety of ways to monitor an installed system including online, an in-home digital panel, or by an application on an Apple phone device. SunPower has installed solar shingles in approximately 4,000 homes to date. The system can also be monitored remotely in order to troubleshoot any problems and potentially prevent a service call.

Also, be sure to check for up-to-date federal and state tax incentives, as they have changed in recent years. Currently, homeowners can receive up to 30 percent rebate of the installation costs 60 to 90 days after installation.

How much does a solar shingle system cost?

Unfortunately, there is no easy answer to the cost of a solar shingle system. Once you have contacted a dealer, you will then need to work through the equation that will lead you to your final price. Both Fox and Kendrick said that the cost will depend on how much energy you use and not the size of your home. “The array size depends on demands,” said Kendrick. You also have to take into account where you home is actually located and how much sun your roof receives.

However, Fox said that solar shingles generally cost in the range of $62.50 per square foot – not including installation or inverters. “It costs 30 to 40 percent more to install on your home than a traditional roof,” said Fox. “But you are also looking at a four to five year payback,” he added.

The additional benefit to installing solar shingles or similar products is not only saving money on your electric bill, but generating credits as surplus feeds back into the grid. You may have the pleasure of actually seeing your electric meter spin backwards.

Various companies offer a range of financing options, from 5 to 25-year loans, to leasing options. The downside to leasing is you don’t own the system, if you sell your home the leasing company has to approve the new owner. Also, you will pay a monthly fee that often negates the financial benefits of having a solar powered electrical system.

It often takes a long time and a good deal of money to bring new technology to the marketplace according to Fox. But the good news is more clean energy products are on the way.

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