Best solar companies California Alameda County Castro Valley
Every company below has verified installations at Castro Valley addresses in public utility records. Review scores are computed from every published customer review. 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 Castro Valley installs are not listed; many also build across Alameda County and beyond. See the full Alameda County ranking →
| # | Installer | |||||||
|---|---|---|---|---|---|---|---|---|
| 1 | Sunrun Installation Services | 52 | 233 | 2014 | 41.2% | Not yet scored | Get a direct bid | |
| 2 | Sunrun | 50 | 471 | 2014 | 87.5% | 6.6 | Get a direct bid | |
| 3 | Bright Ops | 40 | 49 | 2024 | 75.5% | Not yet scored | Get a direct bid | |
| 4 | Tesla Energy | 37 | 607 | 2007 | 14.7% | 6.8 | Get a direct bid | |
| 5 | Synergy Power | 17 | 145 | 2017 | 0.0% | Not yet scored | Get a direct bid | |
| 6 | Solar Optimum Design & Electrical | 14 | 57 | 2020 | 0.0% | Not yet scored | Get a direct bid | |
| 7 | Freedom Forever | 13 | 40 | 2018 | 37.5% | 6.9 | Get a direct bid | |
| 8 | Semper Solaris | 11 | 112 | 2015 | 0.9% | 7.7 | Get a direct bid | |
| 9 | Your Energy Solutions | 8 | 70 | 2019 | 0.0% | Not yet scored | Get a direct bid | |
| 10 | Nrg Clean Power | 8 | 40 | 2018 | 0.0% | 6.7 | Get a direct bid | |
| 11 | American Array Solar Electric | 5 | 25 | 2022 | 0.0% | 7.4 | Get a direct bid | |
| 12 | Nexus Energy Systems | 5 | 24 | 2016 | 4.2% | Not yet scored | Get a direct bid | |
| 13 | High Definition Solar Construction | 5 | 19 | 2020 | 0.0% | 6.4 | Get a direct bid | |
| 14 | Hooked On Solar | 3 | 45 | 2018 | 0.0% | 7.4 | Get a direct bid | |
| 15 | ESP Contracting | 3 | 13 | 2019 | 46.2% | Not yet scored | Get a direct bid | |
| 16 | Clean Solar | 2 | 21 | 2012 | 0.0% | 8.1 | Get a direct bid | |
| 17 | Solar Technologies | 2 | 20 | 2013 | 0.0% | Not yet scored | Get a direct bid | |
| 18 | United Solar Electric | 2 | 17 | 2020 | 0.0% | Not yet scored | Get a direct bid | |
| 19 | Rockin Roofers | 2 | 11 | 2020 | 9.1% | Not yet scored | Get a direct bid | |
| 20 | SunPower Corporation | 1 | 232 | 2016 | 6.5% | 6.2 | Get a direct bid |
Solar.com Scores are live for 26 of the 48 ranked companies. Companies marked “Not yet scored” have fewer than 20published reviews 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); it is separate from the install ranking and never for sale.
The table ranks every established company with recorded Castro Valley installs by recent activity in public utility interconnection records, and 26 of them carry Solar.com Scores computed from every published customer review. 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.
By recent 2025-26 installation activity recorded for Castro Valley addresses in CPUC interconnection records, with all-time installs as the tiebreak. Review scores are shown alongside but never change the activity ranking, and no company can pay for placement.
Where a company clears the 20-review floor, its Solar.com Score summarizes every published customer review, 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.
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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.