Solar and Energy Calculators
Run the savings math with numbers you actually know.
Solar payback depends on your tariff, shade, net metering rules, and incentives that change by year and location. This calculator does not invent a federal credit from your ZIP code. You enter usage, rate, system size, peak sun hours, derate, optional incentive percent, and system cost. It estimates annual production and simple payback. It is not a shade study, an interconnection application, or a finance offer. If a salesperson’s savings number cannot be reproduced from these inputs, ask why.
Calculators
How to measure
Pull 12 months of kWh from your utility bill. Use the $/kWh you actually pay, including delivery charges if that is how you are billed. Peak sun hours vary by region (often roughly 3.5–6.5 in the Lower 48). A site survey beats a map pin.
Related categories
FAQ
- Why don’t you auto-fill the federal tax credit?
- Incentive rates and eligibility change, and not every household can use a tax credit. Entering 0% or the current percentage yourself is more accurate than a hardcoded marketing number.
- What is a derate factor?
- Real systems lose output to inverter efficiency, soiling, wiring, temperature, and mismatch. A derate around 0.75–0.85 is a common planning band. Your designer should use a better production model.