Daily kWh = System kW x Sun Hours x 0.8
Enter your current electricity bill, rate, and system details. The calculator estimates energy production using an 80% efficiency factor, computes financial savings with degradation over 25 years, and accounts for tax credits or incentives to determine your payback period and ROI.
A Solar Savings Calculator helps you estimate the financial and environmental benefits of installing solar panels on your home or business. It takes into account your current electricity costs, local sunlight conditions, system size, installation costs, and available tax incentives to project your savings over the typical 25-year lifespan of solar panels.
The calculator also factors in panel degradation, which is the gradual decrease in energy output over time (typically 0.5% per year). This gives you a realistic picture of long-term savings rather than an overly optimistic flat projection.
Start by entering your average monthly electricity bill and the rate you pay per kWh (found on your utility bill). Enter the average peak sun hours for your location -- this is the number of hours per day when sunlight intensity equals 1,000 watts per square meter. Check the reference table or look up your location on a solar irradiance map.
Choose your desired system size in kilowatts. A typical residential system ranges from 4-10 kW. Enter the installation cost per watt (average is $2.50-$3.50 in the US). Include any tax credits or rebates as a percentage (the US federal solar tax credit is currently 30%). The degradation rate is typically 0.5% per year for quality panels.
The payback period is the number of years it takes for your cumulative electricity savings to equal your net system cost (after incentives). After the payback period, every dollar saved is pure profit. Most residential solar systems pay for themselves in 6-12 years, depending on local electricity rates and sunlight conditions.
Net Metering
Many utilities offer net metering, where excess solar energy you generate is fed back to the grid and credited to your account. This means you can offset nighttime usage with daytime overproduction, maximizing your savings.
Increasing Electricity Rates
Electricity rates typically increase 2-4% annually. This calculator uses current rates, so your actual savings over 25 years will likely be higher as utility rates continue to rise while your solar energy remains free.
Orient panels south-facing (in the Northern Hemisphere) and ensure minimal shading from trees or nearby structures. Consider your roof age -- if your roof needs replacement within 10 years, it may be more cost-effective to replace it before installing panels. Clean panels regularly and monitor system performance to detect any issues early.
Pair solar panels with a battery storage system to store excess energy for nighttime or cloudy days. This reduces your grid dependency further and can provide backup power during outages. Also, shift high-energy tasks like laundry, dishwashing, and EV charging to peak solar production hours (10am-3pm) to maximize self-consumption.
Important Note
This calculator provides estimates based on average conditions and the values you enter. Actual solar production varies with weather, panel orientation, shading, and equipment efficiency. Get multiple quotes from certified solar installers for accurate system sizing and cost estimates specific to your property.