There are many factors involved in determining savings such as utility rate, roof orientation, shading, available roof space for equipment, and energy usage habits. The amount of money that your solar electric system can save you depends on the size and number of your photovoltaic modules and the specific geographic conditions of your site. A properly sized solar thermal system can provide about 80% of your annual hot water needs. Considering that a water heater can account for up to 1/3 of your annual energy bill, a solar thermal system can reduce your annual bill by up to 25%