Solar Proposal Software with Google Maps: Criteria and Comparison

The planning of photovoltaic (PV) systems has become increasingly precise and efficient thanks to the integration of Google Maps. Modern solar proposal software leverages satellite imagery, up-to-date solar irradiation data, and digital tools to optimally size solar installations. This article explains the advantages of using Google Maps in PV system design and highlights the differences between free PV design tools and professional solar proposal software solutions.

Using Google Maps in PV system planning

Solar proposal software with Google Maps is increasingly used for PV system design. These tools enable quick, remote analysis of rooftops and properties to assess their suitability for solar installations and to draft initial system layouts.

A typical workflow for PV planning with Google Maps includes:

• Rooftop Area Capture: The roof of the building is marked and measured directly on the map. Precise identification of the roof’s shape, size, orientation, and tilt is crucial to determine the available area and optimal placement of solar modules.
• Obstacle Mapping: All relevant obstacles, such as chimneys, skylights, HVAC units, or other structures, are drawn in. These may cast shadows or hinder installation and must be excluded from the module layout.
• Considering Trees and Surroundings: Trees and other potential sources of shading around the roof are marked to simulate their impact on solar irradiation.
• Shading Analysis: AI-powered tools and weather data allow for hourly and seasonal shading analysis. This helps estimate how much sunlight the roof receives and the potential energy yield.
• Module Layout and Component Planning: Based on the collected data, solar modules are virtually placed. Inverters and, if applicable, battery storage systems are then sized accordingly.
• Yield and Financial Forecast: The software provides an estimate of the expected electricity yield and potential savings. This forms the basis for the customer proposal.
• Cost and Financing Overview: Finally, a cost calculation and, if desired, financing options can be generated.

What to Consider when using Google Maps for PV Planning

While using Google Maps for PV planning offers many advantages, there are also some limitations:

• Accuracy and Data Currency:
  The image resolution of Google Maps (and Google Earth) is generally sufficient for preliminary planning but may fall short for detailed design. Small obstacles, rooftop structures, or precise roof edges may not be visible.
  
  Satellite images are not always up to date. New constructions, renovations, or changes in the surroundings (e.g., grown trees) may not be reflected.

• Limited Perspectives:
  Google Maps typically provides only top-down and a few oblique views. For accurate module tilt planning and to assess shading from different directions, additional data sources (such as drone imagery) are often needed.

• Missing Terrain Data:
  Elevation profiles and exact roof inclinations can only be partially captured with Google Maps. However, these details are crucial for optimal module orientation and tilt.

• Safety Margins and Codes:
  Legal requirements and technical standards must be observed during planning, such as distances to roof edges, lightning protection, or escape routes. These are not automatically considered in Google Maps and must be manually included.

Key features of a Solar Proposal Software

A robust solar proposal software should offer the following core features:

• Precise Rooftop Mapping: Accurate digital delineation and measurement of the roof shape using satellite imagery, including roof tilt and orientation.
• Shading Analysis: Identification and inclusion of potential shading from trees, neighboring buildings, or other objects in the system design.
• Real-Time Visualization: Immediate display of planned module placement and expected solar yield directly on the aerial image.
• Integration of Irradiation Data: Use of site-specific weather and irradiation data for realistic yield forecasting.
• User-Friendliness: Digital, fast, and location-independent planning—often eliminating the need for on-site visits or software downloads.
• User-friendly Proposal: Report to the client including all relevant data.

The differences between free PV design software and professional tools for solar proposal creation are illustrated below using two examples: Fronius Solar.creator (free PV design software) and Polysun SPT (professional solar proposal software).

Free vs. professional Solar Proposal Software: Key differences

The table below summarizes the main differences between simple free planning tools and professional solutions:

A detailed example of roof planning with Google Maps (using a shed roof) is available in the video below:

Conclusion

Google Maps is highly effective for rapid, remote preliminary planning and proposal generation in PV projects. For professional, highly detailed implementation planning, however, up-to-date roof plans or high-resolution images (e.g., drone photos) and additional data sources are essential. Compliance with technical and legal requirements must always be ensured.

Free tools like Fronius Solar.creator offer an easy entry point but are often limited in module and component selection. Professional tools such as Polysun SPT—with 3D visualization and advanced export functions—are better suited for solar professionals and complex projects. Those who value precision, flexibility, and professional results will benefit in the long run from the expanded capabilities of professional solar proposal software.