Best solar companies California Alameda County Castro Valley
Verified Castro Valley installs, review-backed Solar.com Scores, and the broader county market in one place. Public data, not paid placement.
What this data covers: counts come from investor-owned-utility interconnection records for Castro Valley service addresses. Homes served by municipal utilities interconnect through their city utility instead and do not appear here. Companies with fewer than 10 recorded local installs are not listed; many also build across Alameda County and beyond. See the full Alameda County ranking →
| # | Installer | |||||||
|---|---|---|---|---|---|---|---|---|
| 1 | Synergy Power17 recent installs145 verifiedActive since 20170.0% leased | 17 | 145 | 2017 | 0.0% | 8.9 | Get a direct bid | |
| 2 | Save A Lot Solar1 recent installs10 verifiedActive since 20150.0% leased | 1 | 10 | 2015 | 0.0% | 8.7 | Get a direct bid | |
| 3 | Northstar Solar0 recent installs10 verifiedActive since 20190.0% leased | 0 | 10 | 2019 | 0.0% | 8.6 | Get a direct bid | |
| 4 | West Coast Solar0 recent installs20 verifiedActive since 20150.0% leased | 0 | 20 | 2015 | 0.0% | 8.6 | Get a direct bid | |
| 5 | Clean Solar2 recent installs21 verifiedActive since 20120.0% leased | 2 | 21 | 2012 | 0.0% | 8.5 | Get a direct bid | |
| 6 | United Solar Electric2 recent installs17 verifiedActive since 20200.0% leased | 2 | 17 | 2020 | 0.0% | 8.4 | Get a direct bid | |
| 7 | Century Roof And Solar0 recent installs25 verifiedActive since 20090.0% leased | 0 | 25 | 2009 | 0.0% | 8.4 | Get a direct bid | |
| 8 | Citadel Roofing And Solar1 recent installs11 verifiedActive since 20200.0% leased | 1 | 11 | 2020 | 0.0% | 8.4 | Get a direct bid | |
| 9 | Solar Technologies2 recent installs20 verifiedActive since 20130.0% leased | 2 | 20 | 2013 | 0.0% | 8.3 | Get a direct bid | |
| 10 | Your Energy Solutions8 recent installs87 verifiedActive since 20100.0% leased | 8 | 87 | 2010 | 0.0% | 8.3 | Get a direct bid | |
| 11 | Solar Optimum Design & Electrical14 recent installs62 verifiedActive since 20190.0% leased | 14 | 62 | 2019 | 0.0% | 8.2 | Get a direct bid | |
| 12 | Sierra Roofing And Solar0 recent installs19 verifiedActive since 20160.0% leased | 0 | 19 | 2016 | 0.0% | 8.1 | Get a direct bid | |
| 13 | Powur Home Construction7 recent installs17 verifiedActive since 20220.0% leased | 7 | 17 | 2022 | 0.0% | 8.0 | Get a direct bid | |
| 14 | American Array Solar Electric5 recent installs25 verifiedActive since 20220.0% leased | 5 | 25 | 2022 | 0.0% | 8.0 | Get a direct bid | |
| 15 | Sky Power Systems1 recent installs19 verifiedActive since 20030.0% leased | 1 | 19 | 2003 | 0.0% | 7.9 | Get a direct bid | |
| 16 | All On Electric1 recent installs11 verifiedActive since 20150.0% leased | 1 | 11 | 2015 | 0.0% | 7.8 | Get a direct bid | |
| 17 | Simply Solar2 recent installs16 verifiedActive since 20166.3% leased | 2 | 16 | 2016 | 6.3% | 7.7 | Get a direct bid | |
| 18 | Hooked On Solar3 recent installs45 verifiedActive since 20180.0% leased | 3 | 45 | 2018 | 0.0% | 7.5 | Get a direct bid | |
| 19 | Nrg Clean Power8 recent installs40 verifiedActive since 20180.0% leased | 8 | 40 | 2018 | 0.0% | 7.4 | Get a direct bid | |
| 20 | Semper Solaris11 recent installs112 verifiedActive since 20150.9% leased | 11 | 112 | 2015 | 0.9% | 7.4 | Get a direct bid |
Solar.com Scores are live for 34 of the 46 listed companies. Companies marked “Not yet scored” have fewer than 20 analyzed review texts or are still being analyzed; scores appear as each company's full review record is processed. Select up to 4 companies to compare them category by category.
% leased counts systems recorded as third party owned, meaning a lease or power purchase agreement. The remainder are customer owned. Active installer counts include every company that filed an interconnection that year, down to small and occasional operations. Counts come from PG&E, SCE, and SDG&E interconnection records; homes served by municipal utilities like LADWP, SMUD, and city power departments interconnect through their local utility instead, so companies focused on those territories show fewer records here. The Solar.com Score is computed from the full text of each company's published customer reviews (star ratings and review counts sourced from Google and Yelp), plus verified public-record track record; it drives the default ranking for scored companies and is never for sale.
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The table ranks scored companies by Solar.com Score, computed from customer review evidence and verified track record; 34 companies in this city currently carry a score. Companies not yet scored remain visible below the scored cohort by recent Castro Valley install activity. The best company for your home also depends on your roof, utility, and bid, which is why the same companies compete on price through solar.com.
Companies with enough review evidence are ranked by Solar.com Score. Not-yet-scored companies show a dash in the rank column and sit below them, ordered by recent 2025-26 installation activity recorded for Castro Valley addresses in CPUC interconnection records. No company can pay for placement.
Where a company clears the 20 analyzed-review floor, its Solar.com Score summarizes substantive customer review texts, weighted by reviewer credibility and recency. Select companies in the table to compare their review scores category by category, from sales integrity to long-term support.
Run your address through solar.com. Vetted installers compete on one identical scope for your home, pricing is locked online, and the Best Price Guarantee backs the winning number in writing.
Methodology: Counts are residential PV interconnections in investor-owned-utility territory (PG&E, SCE, SDG&E) per CPUC Rule 21 public records through May 2026. Postal and name variants are merged. Municipal utility territory such as LADWP, Glendale, Pasadena, Burbank, Anaheim, and Riverside Public Utilities is not included in those CPUC counts. Counts show recorded installations, not quality ratings. Reported costs are self-reported on owned-system interconnections. No installer can pay for placement.
Who we are: Solar.com is a solar marketplace — we connect homeowners with installers and earn a fee when projects move forward. These rankings and scores are computed from public installation records and published customer reviews. No installer can pay for placement, and no installer — including those we work with — can pay to change a score.