☀️ Solar Panel Calculator PRO
Estimate system size, energy output, savings, and payback period for solar panel installations.
Dimension Diagram — updates as you type
Roof face with panel layout. Usable area after pitch and shading decides the panel count.
1 Roof Dimensions
Angle affects usable area via cos(angle). 0° = flat, 45° = steep.
2 Panel Specifications
3 Environment & Cost
Average peak sun hours. 4-5 hrs typical, 6-7 in desert climates.
Results
Roof Analysis
System Specifications
Energy Output
Savings & ROI
Cost Breakdown
⚠️ Pre-Export Checklist
- Roof dimensions verified on-site
- Roof structural capacity confirmed for panel weight
- Shading from trees/neighboring buildings assessed
- Local solar permits and HOA requirements checked
- Utility net metering policy confirmed
- Electrical panel capacity verified
- Panel and inverter warranty terms reviewed
Professional Solar Estimation Guide
📐 Formulas & Calculations ▼
Usable Roof Area
UsableArea = Length × Width × cos(angle) × 0.85 (shading factor)
The shading factor accounts for obstructions, setbacks, and orientation losses. Adjust your roof angle to see the impact on usable area.
Panel Count
Panels = UsableArea ÷ PanelArea
Each panel is roughly 17-18 sq ft. A typical 5kW system needs 12-15 panels.
Annual Output
Annual = SystemSize(kW) × SunHours × 365
Output varies by location. 4 sun hours/day is average US, 6+ in Southwest.
Payback Period
Payback = TotalCost ÷ AnnualSavings
Most residential systems pay back in 6-12 years with 25-30 year panel life.
💡 Pro Tips ▼
- South-facing roofs produce 15-25% more energy than east/west in the Northern Hemisphere.
- Micro-inverters are better for partially shaded roofs; string inverters for unshaded arrays.
- Battery storage adds 30-50% to system cost but provides backup power during outages.
- Federal tax credits can offset 30% of total cost — check current incentives in your area.
- Net metering policies vary by utility — confirm buyback rates before calculating savings.
Solar Installation — 3D Preview
Drag to rotate — Scroll to zoom
Calculatrices Connexes
Frequently used together on the same project.
Client & Quote (prints on PDF & Excel)
Adjustments (applies to exports)
Contingency is added as a separate line on the exported cost summary. Waste % is printed as an advisory reminder.
Project notes (prints on PDF & Excel)
Result compare (A/B)
| Item | Pinned | Current | Change |
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Saved rates auto-apply from your Price Library. Advanced details stay in your browser — nothing is uploaded except inside your own PDF/Excel exports.
📖 Comment Utiliser la Calculatrice Solaire
Entrez votre consommation moyenne mensuelle.
Sélectionnez votre emplacement ou heures de pointe.
Choisissez la puissance des panneaux.
Entrez le coût par watt.
Cliquez sur Calculer.
Passez en revue les détails.
📐 Formules d'Énergie Solaire
⚠️ Erreurs de Calcul Courantes
Ne pas considérer les augmentations futures.
Ignorer les ombrages.
Omettre l'état du toit.
Exclure les pertes d'efficacité.
Ne pas inclure tous les coûts.
💡 Conseils Professionnels
Obtenez une évaluation professionnelle.
Considérez le stockage par batterie.
Obtenez plusieurs devis.
Vérifiez les incitations.
Assurez l'état du toit.
Considérez l'orientation.
Surveillez les performances.
❓ Questions Fréquentes
Dépend de la consommation. Un foyer typique nécessite 20 à 25 panneaux.
Le coût moyen est de 2,50 à 3,50 dollars par watt. Un système de 6kW coûte 15 000 à 21 000 dollars avant incitations.
La plupart ont une garantie de 25 à 30 ans.
Oui, ils produisent de l'électricité mais à efficacité réduite, typiquement 10 à 25 pour cent.
Entretien minimal: nettoyage occasionnel et inspections annuelles.
🏗️ Exemples Concrets d'Installation
Utilisez notre calculatrice pour déterminer la taille du système et les coûts pour votre installation solaire.
✅Method, Sources & Review
Maintained by theBuildingCalc methods desk· Last reviewedSeptember 23, 2026. This calculator implements the standards and references below; every figure can be rechecked against the formulas and worked example on this page.
Results are estimates, not engineering advice. Verify against local codes and licensed professionals for structural, electrical, and gas work. See ourTerms. Spotted an error? Report it— corrections ship with the next review.