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| Desired (kW) | Panel (W) | Panel size (m) | Losses (%) | DC/AC | Panels | Module area (m2) | Footprint (m2) |
|---|---|---|---|---|---|---|---|
| 6.00 | 400 | 1.75 x 1.10 | 14 | 1.15 | 20 | 38.50 | 55.90 |
| 10.00 | 450 | 1.90 x 1.13 | 12 | 1.20 | 30 | 64.41 | 96.40 |
| 15.00 | 550 | 2.10 x 1.13 | 15 | 1.10 | 35 | 83.06 | 124.40 |
Start with a desired AC output and account for performance losses. If losses are 14%, the loss factor is 0.86, so 6.0 kW usable output implies about 6.98 kW AC-equivalent before oversizing. Applying a DC/AC ratio of 1.15 raises the required DC size to roughly 8.03 kW, which drives both module count and total area.
Panel wattage converts the DC target into a discrete module count. With 400 W modules, 8.03 kW DC needs 21 modules (rounded up). Physical size then determines module surface. At 1.75 m by 1.10 m, each panel is 1.925 m2, so 21 panels total about 40.4 m2 of module area before any spacing or access allowances.
Real installations need margins beyond module surface. Spacing, tilt/row separation, walkways, and reserve are applied as multipliers. A common planning set of 20% spacing, 10% tilt, 5% walkways, and 3% reserve produces a footprint multiplier near 1.47. Using the example above, 40.4 m2 of modules becomes about 59.4 m2 of estimated footprint.
The calculator can infer efficiency from wattage, area, and irradiance. At 1000 W/m2, a 400 W panel on 1.925 m2 implies about 20.8% efficiency. Using an efficiency method, required DC watts divided by irradiance and efficiency estimates the minimum active area. This cross-check helps spot unrealistic inputs, such as oversized wattage with unusually small dimensions.
Area outputs translate directly into practical constraints. For roofs, compare footprint m2 to usable roof planes after setbacks and obstructions. For ground mounts, convert footprint to ft2 or acres to estimate land needs; 4000 m2 equals about one acre. Pair the footprint with expected racking type and site work to refine budget ranges and timeline assumptions. Sensitivity tests show spacing assumptions often dominate total land requirements overall.
It reflects your target usable output in kilowatts after typical operating conditions. Losses and sizing ratios then estimate the DC array needed to reliably deliver that output.
Many designs oversize DC modules relative to inverter AC rating. A higher ratio increases required module count and area, but can improve energy capture depending on clipping and site conditions.
Allowances are treated as multipliers on module area to approximate real layout needs. Increase them for ground mounts with row separation, and reduce them for tight roofs only when access and code setbacks are satisfied.
Enter efficiency if you know it from the datasheet and want an irradiance-based cross-check. If left blank, efficiency is inferred from wattage, area, and the irradiance input.
No. It estimates minimum active panel area needed to produce the DC wattage at a given irradiance and efficiency. Footprint includes practical space for gaps, access, and layout constraints.
Use them for quick site feasibility and early budgeting. Convert the footprint to land area for permitting discussions, or compare roof-plane square feet against usable sections after obstructions and setbacks.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.