Enter Solar System Details
Example Data Table
| Scenario |
Daily Load |
Sun Hours |
Loss |
Panel Rating |
Battery Days |
Cost Per Watt |
| Small home |
12 kWh |
5.2 |
18% |
450 W |
1 |
$0.70 |
| Medium home |
18 kWh |
5.0 |
18% |
550 W |
1 |
$0.65 |
| Large home |
32 kWh |
4.8 |
20% |
600 W |
2 |
$0.60 |
Formula Used
Performance Ratio = (1 − System Loss ÷ 100) × (Inverter Efficiency ÷ 100)
Required Array Size = Daily Load ÷ (Peak Sun Hours × Performance Ratio)
Panel Count = Ceiling((Array Size × 1000) ÷ Panel Wattage)
Daily Energy = Installed Array Size × Peak Sun Hours × Performance Ratio
Battery Size = (Daily Load × Backup Days) ÷ (Depth of Discharge × Inverter Efficiency)
Inverter Size = Peak Load × Surge Factor ÷ Inverter Efficiency
Simple Payback = Net System Cost ÷ Annual Savings
How to Use This Calculator
Enter your daily electricity use in kilowatt-hours. Add your local peak sun hours. Use a realistic loss value for wiring, dust, heat, and mismatch. Enter panel wattage and available roof area. Add battery, inverter, cost, electricity price, and carbon values. Press the calculate button. The result appears above the form.
Solar Planning Overview
A PV solar power calculator turns daily electricity use into practical system values. It estimates array size, panel count, battery storage, inverter capacity, annual output, cost, savings, and emissions. The tool helps early planning before a site survey. It does not replace a licensed electrical design. It gives a starting point for budgets and comparisons.
Why Peak Sun Hours Matter
Solar panels are rated under test conditions. Real roofs receive changing sunlight through each day. Peak sun hours convert that changing light into one simple daily value. A site with five peak sun hours can produce more energy than a shaded site with three hours. Weather, tilt, azimuth, dust, and heat reduce output.
System Losses and Performance
No system converts all sunlight into usable power. Wiring, inverter conversion, soiling, mismatch, and temperature create losses. This calculator combines loss percentage and inverter efficiency into a performance ratio. The ratio adjusts the rated array output. A lower ratio means more panels are needed for the same load.
Panel Count and Roof Space
The calculator divides the required array watts by one panel rating. It rounds up because partial panels are not possible. It also multiplies panel count by panel area. This check shows whether the available roof space can support the planned array. Extra service paths, setbacks, and mounting gaps may need more area.
Battery and Inverter Sizing
Battery storage depends on daily load, backup days, voltage, and depth of discharge. Lower discharge limits protect batteries but increase required capacity. Inverter size depends on peak load and surge factor. Motors, pumps, and compressors can need extra starting power. Always compare the estimate with manufacturer limits.
Cost, Payback, and Savings
Installed cost per watt gives a rough project cost. Incentives reduce the net cost. Annual savings come from expected energy production and electricity price. Simple payback divides net cost by yearly savings. Actual bills can differ because tariffs, export rules, demand charges, shading, and seasonal use all matter.
Best Use of Results
Use the result as a planning guide. Test several sun hour values and loss rates. Compare a small battery with a larger backup design. Save the CSV or PDF for discussion with installers. Good inputs create better estimates.
FAQs
What is a PV solar power calculator?
It estimates solar array size, panel count, energy production, battery capacity, inverter size, cost, savings, and payback from your basic system inputs.
What are peak sun hours?
Peak sun hours express daily solar resource as equivalent full-power sunlight hours. Higher values usually mean more solar energy from the same array.
Why does the calculator include system losses?
Solar systems lose energy through heat, wiring, inverter conversion, dirt, shading, and mismatch. Losses make real output lower than panel nameplate rating.
Can I enter my own array size?
Yes. Enter a target array size in kilowatts. Enter zero when you want the calculator to size the array from daily energy use.
How is panel count calculated?
The selected array watts are divided by the watt rating of one panel. The answer is rounded up because partial panels cannot be installed.
Does roof area include spacing?
The result uses panel face area only. Real installations may need extra space for walkways, setbacks, tilt rows, clamps, and safety access.
How is battery size estimated?
Battery size uses daily load, backup days, depth of discharge, and inverter efficiency. A lower discharge limit increases required battery capacity.
Is simple payback the final financial return?
No. Simple payback ignores loan interest, degradation, maintenance, tariff changes, export credits, and taxes. Use it as a quick planning indicator.