Ratings Methodology for Solar Panel Installers

NerdWallet’s overall ratings for solar panel installers are weighted averages of ratings in the following categories:
  • Financing terms.
  • Responsiveness to service requests.
  • Customer satisfaction.
  • Number of years in solar.
  • Pricing transparency.
  • Warranty coverage.
  • Customer service options.

    • Data collection and review process

    NerdWallet reviews the largest residential solar installers in the U.S. based on market share and search volume (as a proxy for consumer interest). We gather information from installers’ websites and contact installers for further information.

    The final output produces star ratings from poor (1 star) to excellent (5 stars). Ratings are rounded to the nearest half-star.

    Information updates

    Our writers and editors review providers on an annual basis. Throughout the year, we may maintain contact with providers and update any changes to their offerings.

    Factor weightings

    The weighting of each rating factor is based on our team’s assessment of which features are most important to consumers and which ones impact the consumer experience in the most meaningful way.

    The review team

    The review team comprises writers and editors who cover home services. Each writer and editor follows NerdWallet’s strict guidelines for editorial integrity.

    The combined expertise of our team is infused into our review process to ensure thoughtful evaluation of products and services from the customer's perspective.

    Financing terms

    The highest-scoring installer offers all three of the following options for financing:
  • Loans with under 5% APR.
  • Loans with terms 20+ years.
  • Loans with origination fees of 10% or under.

    • If the installer doesn’t respond to requests for information about financing terms and the terms aren’t found online, we assume the options above aren’t offered.

    The lowest-scoring installer offers none of these options.

    Responsiveness to repair requests

    The highest-scoring installers say they dispatch technicians for repair requests within one week of a request for service. The lowest-scoring installers say they take more than three weeks to dispatch technicians following a request, or they don’t disclose any timeline.

    Customer satisfaction

    NerdWallet averages the customer review scores for installers from three sources: the Better Business Bureau, SolarReviews (a review site that collects consumer reviews of solar panel installers) and ConsumerAffairs (a consumer review site). The highest-scoring installers have average scores of 4 out of 5 or higher. The lowest-scoring ones have average scores of 2.9 or under.

    Number of years in solar

    The highest-scoring installers have been in the solar business for 30 years or longer. The lowest-scoring installers have been in the solar business for four years or less.

    Pricing transparency

    The highest-scoring installers generate pricing estimates for solar panels on their websites for select locations without requiring an email or phone number. The lowest-scoring installers require consumers to provide phone numbers and email addresses to get estimates.

    Warranty coverage

    The highest-scoring installers offer all of the following:
  • Workmanship warranties that are 25 years or longer.
  • Panels and inverters that are covered 25 years or longer.
  • Warranties that cover roof leaks (if caused by solar panel installation).

    • The lowest-scoring installers offer one or none of these types of warranties.

    Customer service options

    The highest-scoring installers meet the following criteria:
  • Their customer service phone number is listed on the website.
  • Their customer service phone number can be found within three clicks from the home page.
  • Service requests can be made through the company’s app or online.

    • The lowest-scoring installers meet one or none of these criteria.
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