Q. What kind of system would I need?
A. Some points you may want to consider in deciding about a solar pv system before you contact a solar company (or DIY).
1. Do you have a south facing section (rooftop or arbor) that receives adequate sunlight, i.e., no nearby trees or building that would shade the area?
2. Check with your utility company to see what system is allowed: i.e. “off the grid” or “grid tied.”? Or what can you afford?
3. Check your utility bills. How much electricity do you use on an average per year. Before we got energy efficient appliances we were using an average of 10.6 KW per day, presently we are using 6.5 KW on average.
4. Choose solar panels to fit your needs. We chose Sharp 165 W(12 panels). California Energy Commission has rated all makes of solar panels by independent testing to help assist people. No solar panel puts out as much as it claims. Therefore, the Sharp 165 W was rated as 144.8 W (not as the manufacturer stated 165 W per panel) but still very good). Multiply that by the number of panels you plan to buy. Therefore, we get 1727.6 W from them under optimal conditions (144.8 times 12 panels in our case). As for a SMA inverter, we purchased a 1800 Sunny Boy. If you want your PV system to store excess in batteries, you would have purchase a Sunny Boy 2500.
5. “How much PV you need depends on your power loads and their duty cycles. If you want to completely replace your current electrical purchases from the utility with a PV system, you could look at your kWh usage on your electric bills for a year, calculate a daily average, and divide that by the number of average daily sun hours for your location. For example: 3600 kWh/yr divided by 365 days/yr equals approximately 10 kWh/day, divided by 5 sun-hours per day (for locations in middle America), equals 2 kW. This would indicate that a 2-kW system would, over the course of an average year, produce enough energy to replace the power you are currently using.”
In addition, besides solar panels that are placed on roofs there are available models that are freestanding units and quite inexpensive.