Calculating ROI For Solar Panels: Which Factors Matter?

Understanding System Costs

To calculate the ROI for solar panels, you must first determine the total system cost, which includes the initial investment in the panels, inverter, mounting hardware, and any additional components. This cost can range from $2.50 to $4.50 per watt, depending on the system size and type of equipment used. For example, a 5-kilowatt system might cost between $12,500 and $22,500.

Calculating Annual Energy Production

Next, you need to estimate the annual energy production of the solar panel system. This can be done using a solar panel performance ratio, which takes into account factors such as module efficiency, inverter efficiency, and system losses. A typical solar panel system might produce between 1,500 and 3,000 kilowatt-hours (kWh) per year, depending on the system size and geographical location. For example, a 5-kilowatt system in a sunny location might produce 2,400 kWh per year.

Determining Savings and Payback Period

To calculate the ROI, you must also determine the annual savings on utility bills and the system’s lifespan. This can be done by multiplying the annual energy production by the cost of electricity in your area and subtracting the system’s operating and maintenance costs. For example, if the system produces 2,400 kWh per year and the cost of electricity is 15 cents per kWh, the annual savings would be $360. By dividing the system cost by the annual savings, you can determine the payback period, which is typically 5 to 10 years for off-grid systems.