Frequently Asked Questions

Almost any building with a sunny roof which faced in a southerly direction is suitable for installation. The closer the roof is to true south the better, although roofs which face east or west work well with an annual performance drop of about 15%, which means the owner has to install a few more modules to make up for the off-south orientation.

The size of the system depends on the amount of southerly roof area one has on their roof. Typically, a 2 kilowatt system employs about 200 square feet of roof space, a 5 kilowatt system 500 square feet of roof space, and a 10 kilowatt system about 1000 square feet of roof space. The California Solar Initiative Program (CSI) allows the owner to generate 100% of their historical demand, providing they have adequate roof space. Normally, systems are sized to meet 25-95% of their total annual electric demand, with the balance of their electricity purchased from the electric utility.

Conservatively speaking, without hyping the performance of these systems, a 2 kilowatt system will generate (save) 200 kilowatt hours of electricity per month, a 5 kilowatt system will generate 500 kilowatt hours of electricity per month, and a 10 kilowatt system 1000 kilowatt hours of electricity per month. The figures reflect the average generation per month over a period of twelve months, and take into account lower winter and higher summer generation. You can use the Clean Power Estimator from the PG&E website to estimate the savings at your home.

CalWest Solar will perform a free site survey of your home. We will take a compass reading of the site and look for any shading which would diminish performance of the system. We will also look at your electric bill, measure the roof, and let you know about how big a system will fit on your roof, within your expected budget range. The person performing the site survey will also be able to answer questions on placement of solar modules and inverters, wire runs , and connections to your main circuit breaker box. They will then take this information back to the office and a proposal will be written and mailed to the owner with all the technical forms and program application filled out.
When the owner decides to go ahead with the installation of the system, they mail the application, technical worksheet, and basic site plan to the administrator of the CSI Program. They will receive written approval of their system along with the rebate amount which will be paid at the end of the installation. An electrical and building permit will be pulled before work can begin. CalWest Solar takes care of all permitting and submits the applicable electrical drawings and roof loading specifications to the local electrical and building code officials. Once the permits are approved, the installation is ready to begin.
When the installation is completed, usually in 2-4 days, the Installer explains operation of the system to the homeowner and calls for the local electrical and building inspection. Once the System passes the local code inspections, the Final Rebate Application is sent in, along with proof of purchase,proof of successful local code compliance, an amended technical worksheet if any changes are made, and a copy of the interconnect agreement.

Presently, A solar electric system, combined with energy efficiency improvements, can substantially reduce your electric bill. Right now, your system can qualify for $2.50 a watt - 30% of a typical residential installation!

Not at all. The modules are installed at the same angle of the roof and look like skylights. They have glass tops with blue or black crystalline cells underneath, and can actually enhance the look of the home. In addition, solar electric systems add value to the home, so a $30,000 system with a rebate of $ 21,000 and a net cost of $9,000 will add at least $9000 to the value of the home upon resale. The electrical savings become dividends.

The aluminum support structure which is underneath the modules are attached directly into the roof rafters of the home.

They are guaranteed to withstand 90-125 mile per hour winds and the weight of the modules is evenly distributed. The modules place a distributed load of less than 3 pounds per square foot on the roof, which is well within roof loading requirements of local building codes. The modules will actually protect the roof shingles under them from the sun, which is the force which cause roof shingles to dry up and curl. In addition, the solar modules block hot summer sun from hitting the shingles, which leads to cooler attic temperatures and decreased cooling costs.

An asphalt-based sealant is placed between the shingle and aluminum support structure to prevent leaks from occurring.

The annual emission offset for a 4 kW system is:

• 4 pounds of oxides of nitrogen
• 18,000 pounds of carbon dioxide
• This is the equivalent of driving your car 22,600 miles per year
• The carbon dioxide absorbed by 2 acres of trees.

As you can see, the environmental savings, when added to the obvious monetary savings, makes solar photovoltaic systems a good investment for the homeowner and society.

Net metering is the term given which allows your utility meter to literally “spin backwards” when you are producing more electricity than you are using. During the day, especially for homeowners, the occupants of the home might be in school or at work while the photovoltaic system is making more than what the house is presently using. The excess electricity then spins the meter backward and the utility gives you credit AT THE RETAIL RATE for the power they buy back from you. This credit shows up on your monthly electric bill as your meter actually registers the backfeed amount. The meter spins forward (you purchase) at night, during rainy weather, or when your electric demand exceeds the amount of power you are generating on the roof at that given moment. For instance, if you are generating 2000 watts of power but only using 1000 watts, you use your own 1000 watts first and sell the excess 1000 watts back to the utility at retail rate. If you are using 2000 watts and only generating 1000 watts at the moment, you use your 1000 watts you generated and only have to purchase the additional 1000 watts from the utility. This amount is annualized at the end of the year, especially during some months when it is possible to have a negative electric bill. It is state law that the utility must interconnect and net meter your system provided your system passes the local electrical inspection (National Electric Code)and meets the utility safety requirments as outlined in the law. A signed copy of the interconnection and net metering agreement is entered into by the Owner and the utility and is binding and transferable, provided the safety requirements are maintained.

All photovoltaic systems we install have a kilowatt hour meter which shows how much the system is collecting at that moment and also totalizes the kilowatts in memory storage. This way, the owner can easily find out how much they have generated daily/monthly/annually and can monitor their system’s performance. There is also a visible back feed number which shows up on the meter so the Owner will know how much electricity they sold back to the utility. These meters are very much like the odometer on an automobile.