Solar Roof Shingles
Solar Roofing Shingles are Gaining Popularity in New Residential Construction
By Mark J. Donovan
New solar roof shingle technology is accelerating in popularity with builders of large housing developments and homeowners alike. In sunny regions of the country, or where electric utility costs are high, solar roof shingles can provide dramatic electric utility cost savings.
Solar roofing shingles , also known as “Building-Integrated Photovoltaics” or BIPVs, integrate solar cell technology into asphalt shingles as well as slate, metal, tile and other roofing products.
At the heart of the solar roof shingle technology is a photovoltaic (PV) semiconductor layer that is laminated to the shingles’ surface. The solar roofing shingles convert the sun’s solar rays into electricity that the home uses. If the solar roof shingles produce more electricity than is consumed by the home, the energy can either be stored in batteries for later use, or more often, fed back to the electric company for an energy credit. When the excess electricity is fed back to the public utility, your electric meter actually turns backwards.
Solar roof shingles look very similar to standard asphalt roof shingles both in size and appearance, and are aesthetically much more attractive than roof mounted solar panels. Many have a deep dark bluish/purple appearance and blend in well with existing asphalt roof shingles. The manufacturer SunPower also offers them in a black appearance.
Depending upon the home’s electrical needs, all or only a portion of a roof need be shingled with solar roof shingles. If a partial roof installation is all that’s required, the solar roof shingles will integrate smoothly into the standard asphalt roof shingle areas.
Solar roofing shingles are installed similarly to traditional asphalt shingles however they should only be installed by a roofing professional or electrician who has been trained by the particular solar roof shingle manufacturer. Besides having to properly install them, the roofer or electrician also needs to run wires behind the roof sheathing and into the attic space.
From there the wires are connected together and sent to an inverter box that converts the DC voltage to AC voltage. The AC voltage can then be fed into the home’s electrical system and/or onto the utility grid. The material and installation costs for installing solar roof shingles is still much hirer than standard asphalt roofing shingles, however they are falling. In addition, the electric utility costs savings can be dramatic depending upon the amount of sun your home’s roof is exposed to and/or the cost of electricity in your local area.
Also, the federal government offers a 30% tax credit, or up to $2,000 in savings, on the cost of installation. Typically you can expect to see a return on your investment within 5 to 10 years, however this number is a function of how much sunlight your roof is exposed to and the cost of energy in your local area.
The average single solar roof shingle with approximately 3 square feet of exposure can only produce 50 watts of power, enough to run a low wattage incandescent light bulb on a sunny day. However when hundreds of square feet of roof surface is covered in solar roof shingles, combined they can produce enough electricity to run an entire home. The standard rule of thumb is that a home requires 1KW (1000 watts) per every 1000 square feet of living space. Consequently on a 2,000 square foot home, approximately 120 square feet of solar roof shingles are required. The cost of installing a 2KW solar roof shingle system is estimated to be around $15 - 20K, before applying for the federal tax credit.
Warranties for solar roof shingles range from around 15 to 20 years and are designed to withstand rain, snow, and wind. Most solar roof shingle manufacturers state that their shingles can withstand 80 MPH wind loads. Solar roof shingle manufacturers include OkSolar, Uni-Solar, SunPower, Solar Components Corporation, Dow Chemical and Atlantis Energy Systems. Atlantis Energy also offers a roofing product called BITERS that delivers both electricity and hot water to the home. So if you are planning to build a new home you may want to take a closer look at solar roof shingles. They can provide your home with both weather protection and clean electricity, and can dramatically reduce your energy bills. In addition, as electric utility costs continue to rise and solar roof shingles conversely fall in price, the time for seeing a return on investment continues to shrink.
