Frequently Asked Questions
How accurate is this calculator?
We use government-grade solar irradiance data from the National Renewable Energy Laboratory (NREL) API. This takes into account your specific latitude, longitude, and historical weather patterns. We combine this with 2025 utility rate averages to give you a highly precise estimate, typically within 5-10% of a professional quote.
What is the 30% Federal Tax Credit?
The Investment Tax Credit (ITC) allows you to deduct 30% of the cost of installing a solar energy system from your federal taxes. This applies to both residential and commercial systems, and there is no cap on its value.
Why does my Payback Period vary by city?
Two factors change by location: Sunlight Hours and Electricity Rates. A home in San Diego (High Sun + High Rates) will pay for itself much faster than a home in Seattle (Low Sun + Low Rates). Our tool calculates this specific intersection for your zip code.
Do solar panels increase home value?
Yes. According to Zillow, homes with solar panels sell for approximately 4.1% more than comparable homes without them. This added value is often not included in standard ROI calculations, meaning your actual return is likely higher.
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