Solar Panel ROI Calculator: Payback Period & Savings Estimator (2026)

Running an air conditioner during India's peak summer months is the single largest contributor to residential electricity bills. A standard 1.5-ton inverter AC running eight hours daily consumes between 1,100 and 1,500 kWh across a summer season — costing households ₹8,000 to ₹15,000 depending on state electricity tariffs. For families using AC in multiple rooms, these costs multiply rapidly.

Solar photovoltaic (PV) panels offer a practical, increasingly affordable solution. India receives an average of 4.5 to 6.5 peak sun hours per day across most states — making rooftop solar one of the most effective investments available. A well-designed system can offset 85–100% of AC electricity consumption, reducing monthly bills to near zero during peak summer.

The economics have improved dramatically. Solar PV module costs have fallen over 90% in the last decade. Combined with the PM Surya Ghar Muft Bijli Yojana scheme offering up to ₹78,000 in central subsidies, and state-level top-ups in states like Gujarat and Maharashtra, payback periods now range from 3 to 5 years — after which power is essentially free for the remaining 20+ years of panel life.

How to Size a Solar System for Your AC

The key formula: System Size (kW) = (AC Watts × Usage Hours) ÷ (1000 × Peak Sun Hours). For a 1.5-ton 5-star inverter AC (≈980W) running 8 hrs/day in Delhi (5.5 peak sun hrs): (980 × 8) ÷ (1000 × 5.5) = 1.43 kW system. Rounding up to 1.5–2 kW handles inverter losses and cloudy days.

Always add 20–30% buffer to your AC load calculation to account for other household loads (refrigerator, fans, lights) that run simultaneously. For a home with 1 AC + full household loads, a 3 kW system is typically the sweet spot — and it's also the maximum size that attracts the highest PM Surya Ghar subsidy of ₹78,000.

On-Grid vs Off-Grid vs Hybrid Solar Systems

On-Grid systems are the most popular and cheapest. They connect directly to the utility grid and enable net metering. However, they shut down during grid outages — a limitation in areas with frequent load shedding.

Off-Grid systems with battery storage ensure 24/7 operation but add 35–50% to total system cost. Recommended only in areas with 4+ hours of daily load shedding.

Hybrid systems combine grid connectivity with a battery bank. They export excess power during the day, charge batteries when not needed, and provide backup during outages. Best overall ROI for urban Indian households with occasional power cuts.