Key takeaways: Solar panel calculator: Sizing formula: kW = Daily kWh ÷ (Peak sun hours × System efficiency). Use 0.80–0.86 for efficiency (NREL PVWatts default is 0.86). Worked example: a 10,500 kWh/year home at 5.0 peak sun hours needs 6.7 kW, which is 16 × 420W panels (panel count = kW × 1,000 ÷ panel […]

Key takeaways: Solar savings calculator: Savings math: (kWh you use yourself × retail tariff) + (kWh you export × export tariff) − remaining grid charges, minus the net system cost. EnergySage’s June 2026 analysis: the average US homeowner saves about $60,500 over 25 years, ranging $41,000–$155,000 by state. Assume 70–80% self-consumption without a battery; a […]

Key takeaways: Solar payback calculator: Payback = Net System Cost ÷ Annual Savings; the accurate version splits savings into self-consumed kWh (full retail rate) and exported kWh (lower export rate). Realistic 2026 ranges: UAE 2.5–4 years, Australia and India 3–6, the US and UK 8–12, Norway 20–25+. US warning: the 30% residential tax credit ended […]

Key takeaways: Solar battery size calculator: Size with the formula: kWh = daily backup kWh × backup days ÷ depth of discharge ÷ efficiency. A 10 kWh/day home at 90% DoD and 90% efficiency needs 12.3 kWh of rated storage. Usable energy is what counts: lithium (LiFePO4) gives 80–95% usable, while lead-acid allows only about […]

Key takeaways: How many solar panels: The industry formula: daily electricity use (watt-hours) ÷ peak sun hours ÷ panel wattage = number of solar panels. The average US home (about 30 kWh per day) needs 13 to 19 panels of 400 W each; 400 W is the most popular residential panel rating. Worked examples (4.5 […]