You’ve read the articles, ‘surfed’ the web, and are ready to commit to installing Solar for your home. Installing a Photovoltaic Solar System for your home is a wise decision on many levels. Like many home improvements, it doesn’t happen overnight. However, with proper planning, you’ll know what to expect and can start the process with confidence.
Estimated time required: A few days
Gather electric bills:
To a large extent, the size of your solar PV system will be determined by your current electricity usage. Must collect a year’s worth of electricity bills. Copies can be obtained from your utility company and are often available online. Your solar contractor will use this information to determine how many panels you’ll need, what size panels you’ll need, and what type, number, and size of inverters you’ll need. Your electricity usage information is also helpful in determining your payback period – how long it will take to recover your investment.
Estimated time required: Less than 2 weeks
Find a certified contractor:
There are various sources of contractor names: Internet, solar organizations, recommendations. Your contractor must have the required state electrical license. If the person you are dealing with is not licensed, they are likely just a sales organization that will outsource much of the work to others. You will have no say in who these others are, so make sure you trust the people you hire. Your contractor must also be registered as a NJ State Home Improvement Contractor. This registration is required for all businesses or individuals that perform work on NJ housing. Being a member of one of the national solar associations is also a good guide. These certifications and licenses must be displayed on the contractor’s website. If you don’t see them, ask to be sure.
Estimated time required: 1 week
Solar Site Survey:
To get started, your contractor will use ‘Google Earth’ or a similar satellite mapping service to initially verify the suitability of your location. He/She will look to see if your roof can be seen from the satellite. Trees or other obstructions Careful examination of the home is required if a solar installation is appropriate. The contractor will then go up to your roof, if it’s accessible, and take critical measurements. They will draw a plan of the roof, locating all existing roof penetrations such as vents, exhaust pipes, chimneys, and determine the general condition of your roof and how old it is. If your roofing material is near the end of its useful life cycle, it may make sense to have it repaired/replaced prior to the installation of a roof-mounted solar panel system.
Next, they will use an inclinometer to check the slope of the roof. This is important for two reasons. First, the slope of the roof relative to the latitude will affect the amount of sun the panels receive and therefore the amount of electricity they produce. Second, a roof with a steep slope will require additional safety equipment such as roof harnesses and roof ladders. This can affect the cost of the installation.
Next, your contractor will check your existing electrical service and main panel. Your new solar photovoltaic system must be properly connected to your panel. An older panel may need to be replaced. Your contractor will also examine your attic. A solar PV system puts additional weight on the roof, and the roof must be able to handle this additional load. The construction of the roof, along with the construction of the attic floor, will determine the load-bearing capacity of your roof. (for more information, see “Local Building Permits” below)
The contractor should also take a compass azimuth reading of your roof. It must be determined where and when the sun will shine on your roof. A north facing roof will not receive direct sun and cannot be used. South-facing roofs are ideal, but other east and west directions will work as well.
The contractor will use a special instrument called a Solar Eye. This is a combination of fisheye camera and computer. Your geographic location is programmed into the device, along with the roof pitch and compass direction. This device will locate any source of shade that may reach your roof, any time of day, any day of the year. Determine what your “insolation” rate will be. Perfect is, of course, 100%. Less than 70% could mean altering the panel mounting pattern to avoid shading. In northern New Jersey, a good roof averages 4.5 hours of usable sunlight per day. When all the parameters are fully known, it becomes a matter of simple geometry. How the largest number of panels will be installed on the given roof surface. Ideally, we like to use the highest wattage panels we can. Installed cost per watt decreases as panel size increases. Panels come in outputs from around 75 watts to over 200 watts.
The final technical calculation required is the selection of the inverter. Its solar panels convert the sun’s energy into direct current electricity. Your house runs on alternating current. The inverter does the work of changing direct current into useful alternating current. The panels are wired together in patterns called “strings” and each “string” is connected to the inverter. The inverter then sends AC power to your main electrical service panel, where it will power your entire home.
With all this information, the contractor will provide you with a preliminary proposal.
Approximate time required: 4 weeks
Permits and your utility company:
Once you agree to a proposal, your contractor will begin dealing with outside agencies…utilities and municipal building departments. You must request a special electrical “net metering” from your electric utility company. Remember, when you generate MORE electricity than you use at any given time, the excess energy goes back into the power grid and your meter works ‘in reverse’, giving you a credit for the power you’ll take from the grid. The utility company will install a special “net metering” meter to accomplish this. Forms for obtaining utility approval are generally available online. Your contractor will obtain and file them for you.
Approximate time required: 2 weeks
When your contract is complete and signed, you or your contractor will request your reimbursement from the State of NJ. Refund requirements and forms are available online.
You will also need to open an account with the State of New Jersey for SREC – Solar Renewable Energy Certificates. SRECS represents the energy your solar system produces, whether it is used by your home or sent to the grid. You will earn approximately 1.1 SRECS per year for every KW of installed solar capacity you have. SRECs have an average New Jersey value of $527.00 as of July 2009. Approximate time required 2-4 weeks
We have found that the most time consuming aspect of the project can be getting your permit from the local building department. Most building departments have little or no experience with solar installations. In general, this is what they will probably require: Factory specifications for your solar panels and your inverter.
* A complete wiring diagram of your facility, showing the location of the panels, inverter, disconnect switches, strings, and wiring size.
* Installation instructions and specifications for roof racks, showing specifically how the panels should be mounted and how roof leaks are prevented.
* Roof Load Specifications – The building department wants to make sure your roof can support the additional weight of the panels you will be installing.
The average system adds about 3 pounds per square foot to your roof. Many roofs can easily handle this. Some, however, cannot. You will be required to retain the services of a licensed professional engineer to make that determination. You will provide documentation to the building department that certifies the load-bearing capacity of the roof. In the event that your roof’s load-bearing capacity is insufficient to handle your solar panel system, he will recommend any necessary building improvements. Approximate time for engineering approvals and permits: 4-8 weeks At this point, all paperwork is complete and permits and approvals are ready. Your contractor orders your equipment from the solar provider(s). Equipment delivery is generally within 2 weeks. Your installation will take anywhere from several days to 2 weeks, depending on the nature of your home and system design. Municipal, utility, and state inspections get organized, usually in a week or so, and then… your system fires up.
Your project is complete… now you are enjoying solar energy.
Congratulations!