20 panels fit (3 × 7 in portrait (rows × columns)): 8.6 kWp producing about 10,320 kWh a year. Modules cover 64% of the 61 m² roof surface.
Panels that fit
20
3 × 7 in portrait (rows × columns)
System size
8.6kWp
20 × 430 W
Annual production
10,320kWh
1,200 kWh/kWp
Roof surface
61m²
50 m² on plan, ×1.22 for the slope
Usable area after setbacks
49m²
80% of the roof
Module coverage
64%
39.1 m² of modules
Power density
141Wp/m² roof
Added roof load
14kg/m²
incl. ≈ 3 kg/m² rails
Panels lost to obstructions
1
1 m² of obstructions
Layout options
| Orientation | Layout | Panels | kWp |
|---|---|---|---|
| Portrait | 3 × 7 in portrait (rows × columns) | 20 | 8.6 |
| Landscape | 4 × 5 in landscape (rows × columns) | 19 | 8.17 |
| Mixed | 3 × 7 in portrait + 0 × 5 in landscape | 20 | 8.6 |
Other panel sizes on the same roof
| Panel class | Panels | kWp | kWh/yr |
|---|---|---|---|
| 300 W polycrystalline | 26 | 7.8 | 9,360 |
| 400 W mono PERC | 20 | 8 | 9,600 |
| 430 W N-type TOPCon | 20 | 8.6 | 10,320 |
| 450 W TOPCon | 20 | 9 | 10,800 |
| 490 W TOPCon | 17 | 8.33 | 9,996 |
| 550 W mono PERC | 15 | 8.25 | 9,900 |
| 620 W TOPCon | 13 | 8.06 | 9,672 |
| 700 W HJT bifacial | 11 | 7.7 | 9,240 |
- Each obstruction removes more module positions than its own area because it breaks the grid; the calculator assumes 1.5× its area. Draw complex roofs (dormers, hips, valleys) face by face.
- Pitched-roof setbacks: many codes require fire-access paths (e.g. 0.46–0.91 m in the US) and wind edge zones. Check your local rules and the roof structure.
- Specific yields are inputs: get them for your exact orientation from the solar panel or tilt-angle calculators.