Important Considerations for Solar Electric System Design

• We will perform a detailed shade analysis with a Solmetric SunEye tool to determine the sunniest place for the solar modules. The SunEye includes a digital camera and a dedicated on-board processor to compute shading and solar access percentages. With this tool we are able to determine how much sun your roof receives on any given day and time of the year, allowing us to estimate your eventual electrical production.

• Solar panels work optimally in the Bay Area when facing South or Southwest at a tilt of between 15-35 degrees up from horizontal. West facing arrays are good too if the pitch is less than 23 degrees (steeply pitched west facing roofs may have weak winter performance). With a time-of-use electric meter in PG&E territory, west facing arrays (at tilts less than 22 degrees) give about the same financial value as southern oriented PV systems.

• Inverters operate most efficiently and last longer when located in shady and cool locations (preferably near the electric panel where a circuit breaker connects it to the power). This keeps wire runs short and inexpensive and to a lesser extent reduces wire loss due to voltage drop that may occur for long wire runs.

• PV is relatively maintenance free, just view the inverter output to verify the system is working and clean the panels for maximum performance in the summer (hosing off panels is usually all that is needed, if panels are not cleaned summer output may drop by 3% to 9%). Monitoring systems can be connected to your computer or the internet to automate system performance monitoring. Currently available grid tied PV inverters have built in monitoring displays to show peak power output and cumulative kWh daily and lifetime energy generation.