Saratoga Solar Power Home A solar power system was designed for a 4,000 square foot house in Saratoga. This system included eighteen 165 watt solar energy modules installed on the south roof. Peak power generating capability is 2,970 watts. (based on manufacturer output ratings). This system provides about 4,064 kwh per year -- after taking into account various real-world efficiency losses.                The section below describes the detailed energy bill analysis and system design work we did for the customer Total costs of the solar energy system were $26,604, including all equipment, permits and installation on this concrete tile roof (flashed standoffs were used to prevent leakage). The customer received: $7,873 rebate from the California Energy Commission $4,810 federal and state tax credits combined. Net costs: $13,822. Based on current residential electric rates, a 7% discount rate, 30 year solar energy system lifetime, 5% annual electrical rate increases, 6% borrowing rates, and 42% combined State and Federal tax rates, this system will save the homeowner $800 per year with a Net Present Value of $3,474. According to the Appraisal Institute, energy saving improvements increase your home's value by $20 for every $1 reduction in annual energy usage. In this case the value of the home was increased by $16,000 in current dollars -- more than the net cost of the solar energy system itself! On a cash basis, this customer's electric bill went down by $66.69 per month, and their after tax loan payment went up by $54.51. Their monthly positive cash flow was therefore $12.18. Twelve bucks a month, free and clear for 30+ years! Solar Energy System Design and Energy Bill Analysis Our recommendation to install this particular solar energy system was based on a detailed analysis of the customer's energy bill, roof condition, orientation, house electrical system, local weather conditions, environmental interests, financial goals and aesthetic preferences. This analysis was summarized in a detailed, 50 page report that we presented to the customer. The two bar charts below highlight the results of our before and after energy bill analysis. Note that the solar energy system reduces energy usage in the highest rate tiers first. All of his expensive 300%+ and 300% of baseline usage was eliminated. Since your solar energy savings will vary depending on your monthly usage and output, the only way to accurately model your savings is to compare your before and after consumption on a monthly basis using actual, on-site conditions.     Environmental and Financial Benefits The following two tables summarize the environmental and financial benefits that the solar energy system will provide over its 30+ year lifespan.    These savings do not take into account several important factors: Distributed solar energy power is a renewable energy resource and very kind to the environment. Renewable solar energy system improvements add significantly to the value of your property without any increase in the assessed value in most municipalities. Cash flow savings are likely to be hundreds of dollars per month if you were to install a solar energy system in conjunction with other energy saving devices - and then refinance the entire package at a lower interest rate.