What is Project Sunroof?

Google's Project Sunroof stands out as an innovative initiative that aims to make solar power more accessible to homeowners

Last updated
June 30, 2024
Author: Matt from Currents
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in 2015 by Google engineer Carl Elkin, Project Sunroof has been steadily working towards its mission of "mapping the planet's solar potential, one roof at a time".

This comprehensive tool combines Google's expertise in mapping technology, data analysis, and machine learning to provide homeowners with valuable insights into the solar potential of their properties.

What is Project Sunroof?

Project Sunroof is a free online tool that helps homeowners determine whether solar panels are a viable investment for their homes.

It uses high-resolution aerial imagery from Google Earth, advanced 3D modeling, and machine learning algorithms to calculate the solar potential of a given rooftop. By considering factors such as roof structure, shade from nearby trees or buildings, and local weather patterns, Project Sunroof provides a detailed estimate of a roof's solar energy potential.

The tool's primary function is to encourage the private adoption of solar energy by providing a set of tools that facilitate the purchase and installation of solar panels. It does this by offering:

  1. Personalized solar potential estimates
  2. Recommended solar panel system sizes
  3. Estimated cost savings over time
  4. Environmental impact assessments
  5. Information on local solar providers and financing options

How Does Project Sunroof Work?

The process of using Project Sunroof is straightforward and user-friendly. Here's a step-by-step breakdown of how it works:

  1. Address Input: Users start by entering their address into the Project Sunroof platform.
  2. Data Collection: The tool collects data from Google Maps and Google Earth to analyze the home's roof characteristics and location. This includes information on roof size, orientation, shading, and angle.
  3. 3D Modeling: Using the collected data, Project Sunroof employs 3D modeling technology to determine the home's solar potential. This includes calculating how much sunlight the roof receives daily, how much energy can be generated from solar panels, and potential energy bill savings.
  4. Recommendations: Based on the analysis, Project Sunroof recommends the size, type, and number of solar panels that best suit the homeowner's energy needs.
  5. Cost and Savings Estimation: The tool calculates the estimated cost of installing a solar panel system and the potential energy savings the homeowner can achieve. This includes information on the payback period and the estimated time to break even on the investment.
  6. Results Review: Users can then review the results of the roof analysis and determine the potential benefits of installing a solar panel system.

The Technology Behind Project Sunroof

Project Sunroof leverages several advanced technologies to provide accurate and reliable solar potential estimates:

  1. High-Resolution Imagery: The tool uses high-resolution 3D imagery data from Google Maps to calculate shadows from nearby structures and trees.
  2. Historical Weather Data: Project Sunroof takes into account historical weather and temperature patterns to provide more accurate estimates.
  3. Machine Learning Algorithms: These algorithms help generate a virtual model of a homeowner's roof, including accurate measurements of roof dimensions and shading from obstructions.
  4. 3D Modeling: This technology allows for a detailed analysis of roof characteristics and solar potential.
  5. Data Explorer: In addition to individual property assessments, Project Sunroof offers a Data Explorer feature that allows users to view aggregated solar insights for entire communities or cities.

Benefits of Project Sunroof

Project Sunroof offers several advantages to homeowners considering solar energy:

  1. Ease of Use: The tool is intuitive and doesn't require a steep learning curve. Users can get valuable information about their roof's solar potential by simply entering their address.
  2. Cost-Free Analysis: Project Sunroof is a free online tool, making it accessible to all homeowners interested in exploring solar energy options.
  3. Comprehensive Information: The tool provides a wealth of information, including estimated energy generation, potential savings, and environmental impact.
  4. Data-Driven Decision Making: By providing accurate, data-driven estimates, Project Sunroof helps homeowners make informed decisions about investing in solar energy.
  5. Environmental Impact Assessment: The tool helps users understand the potential reduction in their carbon footprint by switching to solar energy.

Limitations and Considerations

While Project Sunroof is a powerful tool, it's important to be aware of its limitations:

  1. Limited Availability: Currently, the tool is only available in the United States and Germany.
  2. Outdated Data: The tool hasn't been updated since 2018, which may affect the accuracy of some estimates, particularly regarding changes in federal solar tax credits.
  3. Focus on Rooftop Solar: Project Sunroof is primarily designed for rooftop solar systems and doesn't provide data for alternatives like ground-mounted solar systems.
  4. Estimation Limitations: While the tool provides valuable estimates, it can't calculate the exact energy solar panels will generate due to variables like panel quality and installation specifics.
  5. No Local Provider List: Unlike some other solar calculators, Project Sunroof doesn't provide a list of local solar providers.

Project Sunroof vs. Other Solar Calculators

While Project Sunroof is a popular choice, it's not the only solar calculator available. For instance, EnergySage's Solar Calculator offers some features that Project Sunroof doesn't:

  1. Alternative Solar Options: EnergySage considers alternatives to rooftop solar, such as ground-mounted systems or community solar, when providing estimates.
  2. Up-to-Date Information: EnergySage's tool is regularly updated to reflect changes in solar incentives and other relevant factors.
  3. Comprehensive Marketplace: EnergySage offers a marketplace where users can compare quotes from multiple solar providers.

However, it's worth noting that EnergySage actually incorporates Project Sunroof's data into its own calculations, combining it with custom solar quotes from its marketplace to create accurate cost and savings estimates.

The Impact of Project Sunroof

Since its launch in 2015, Project Sunroof has made significant strides in mapping solar potential across the United States.

As of 2021, the project had analyzed over 60 million buildings across all 50 states. This extensive coverage has helped countless homeowners explore their solar options and has contributed to the broader adoption of solar energy.Moreover, the data collected by Project Sunroof has applications beyond individual homeowners.

In September 2018, Google launched the Environmental Insights Explorer platform, which uses Project Sunroof data to help cities measure their carbon footprint and take action to support their climate goals. This platform provides estimates for a city's annual carbon emissions using detailed geospatial data derived from Google Maps and can estimate the aggregated solar potential of an entire city.

The Future of Project Sunroof

As the world continues to shift towards renewable energy sources, tools like Project Sunroof are likely to play an increasingly important role. While the tool hasn't been updated since 2018, its underlying technology and approach remain valuable.The future of Project Sunroof could potentially include:

  1. Expanded Geographic Coverage: Extending the tool's availability to more countries around the world.
  2. Integration with Smart Home Systems: Potentially linking with smart home energy management systems to provide real-time solar potential data.
  3. Enhanced Machine Learning: Further refining the tool's algorithms to provide even more accurate estimates.
  4. Incorporation of New Solar Technologies: Adapting to include newer solar technologies as they become available for residential use.


Google's Project Sunroof represents a significant step forward in making solar energy more accessible and understandable for homeowners.

By leveraging Google's vast data resources and advanced technologies, the tool provides valuable insights that can help individuals make informed decisions about investing in solar energy.While Project Sunroof has its limitations and hasn't been updated recently, it remains a useful starting point for anyone considering solar power. Its user-friendly interface, comprehensive analysis, and cost-free service make it an excellent resource for homeowners curious about their property's solar potential.

As we continue to grapple with the challenges of climate change and the need for sustainable energy solutions, tools like Project Sunroof play a crucial role in empowering individuals to take action. By providing clear, data-driven information about the benefits of solar energy, Project Sunroof is helping to illuminate the path towards a more sustainable future, one roof at a time.

Whether you're seriously considering installing solar panels or simply curious about your home's solar potential, Project Sunroof offers a valuable first step in your solar journey. As with any major home improvement decision, it's always advisable to consult with professional solar installers and get multiple quotes before making a final decision.

Project Sunroof, combined with other resources and professional advice, can help you make an informed choice about harnessing the power of the sun for your home.

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