Solar Engineering Tools

Free online calculators calibrated for Kenyan conditions and NASA data, interactive design utilities and links to professional solar power design software.

For Systems < 10 kW
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Off-Grid Express System Sizer

The fastest way to size your system. Just enter your monthly KPLC 'Units' and we instantly calculate your solar panel, battery, and inverter requirements.

Start Sizing
Sizer, auditor, cost estimator
🔍

Sizer, Auditor and Cost Analyser

List your appliances to see what's eating your electricity. Find ways to cut your power bill as you calculate the optimum solar power system. Estimate system cost and return on investment.

Start Detailed Analysis
Solar Thermal
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Solar Water Heater Sizer

Heat water with solar energy. This calculator is based on the Kenya EPRA Energy (Solar Water Heating) Regulations 2025.It uses the solar energy data form NASA resources and accounts for the collector type.

Size Heater

Off-Grid Express Sizer

Quickly calculate your solar requirements based on your monthly KPLC bill.

System Parameters

Sizing Results

Design GHI Used (kWh/m²/day)
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Variability (CV)
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Avg Temp (°C)
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Required Solar Panels
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(e.g., 2 x 400W)
Battery Bank Capacity
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(Ah @ 24V)
Minimum Inverter Size
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(kVA - Handles surges)
💡 Smart Sizing Active: This calculator automatically adjusts panel sizing based on your location's specific temperature (panels lose efficiency in heat) and Variability (uses minimum GHI for high-CV areas to guarantee winter power).

Recommended Professional Software

Tools for detailed shading analysis, 3D modeling, and financial yield predictions.

COMMERCIAL

PVSyst

The undisputed industry standard for detailed PV system design, loss analysis, and bankable energy yield simulations.

Visit PVSyst >
FREE & OPEN SOURCE

System Advisor Model (SAM)

Developed by the US National Renewable Energy Lab (NREL). Incredible for detailed financial modeling, grid-tied analysis, and battery dispatch simulations.

Download SAM >
FREE TIER

OpenSolar

A modern, cloud-based platform. Excellent for fast residential/commercial quoting, 3D roof mapping, and generating beautiful client proposals in minutes.

Try OpenSolar >
FREE TIER

PV*SOL (Valentin Software)

The free version of PV*SOL is fully capable of designing systems up to 100kW. Great 3D shading engine and detailed hourly simulation.

Download Free Version >
COMMERCIAL

HOMER Grid / Pro

The ultimate tool for optimizing hybrid microgrids, grid-tied solar plus storage, and complex off-grid systems with generators.

Visit HOMER >
FREE TIER

SketchUp + Skelion

Use the free version of SketchUp for 3D rooftop modeling, and install the Skelion plugin for automated panel layouts, shading, and string sizing.

Get Skelion Plugin >