Portola Valley, CA 94028 solar market data
Updated April 20, 2026 By The SolarDNA Data Team
Portola Valley 94028 has 1,001 solar installations at a median installed cost of $5.36/W, recent growth not yet measurable, and a Market Score of 38 — higher than 27% of U.S. zip markets.
Versus California
How 94028 compares with the state
Installed cost
$1.09/W above
state median $4.26/W
Market score
38 vs 53
California scores 53
Share of state installs
0.04%
of 2.3M tracked statewide
Battery attach
18.7%
state 12.7%
Statewide momentum
▲ 1.1%
residential solar added in California, 12 months through Jul 2026
Statewide market
2.3M systems
30.9% of homes · utility-reported through Jul 2026
Growth & pricing
94028 by year
45 installs in the trailing twelve months vs 56 before
Installations by year
Median installed cost, $/W DC by year
Installer comp set
Who installs in 94028
Ranked by systems recorded in this zip
| # | Installer | Installs | 12-mo | Avg kW | $/W |
|---|---|---|---|---|---|
| 1 | TESLA | 250 | 4 | 8.07 | $6.62 |
| 2 | COBALT POWER SYSTEMS | 172 | 4 | 10.65 | $5.40 |
| 3 | SEMPER SOLARIS | 24 | 0 | 7.84 | $6.89 |
| 4 | SUNRUN | 23 | 0 | 7.45 | $4.59 |
| 5 | AKEENA SOLAR | 21 | 0 | 8.89 | $7.78 |
| 6 | RGS ENERGY | 20 | 0 | 21.71 | $8.40 |
| 7 | SUNPOWER | 20 | 0 | 7.96 | $5.33 |
| 8 | CLEAN SOLAR | 19 | 0 | 8.01 | $4.59 |
| 9 | ROCKIN ROOFERS | 18 | 3 | 9.85 | $4.50 |
| 10 | BAY AREA ENERGY SOLUTIONS | 17 | 2 | 13.09 | $5.40 |
| 11 | REC SOLAR COMMERCIAL | 17 | 0 | 5.51 | $4.83 |
| 12 | CINNAMON SOLAR | 15 | 0 | 8.16 | $6.08 |
Equipment
What gets installed in 94028
Share of systems with a recorded brand
Modules
SUNPOWER22.1%
QCELLS NORTH AMERICA9.3%
LG ELECTRONICS7.7%
TESLA6.3%
REC SOLAR4.6%
Inverters
ENPHASE ENERGY24.4%
SUNPOWER18.1%
SOLAREDGE16.5%
XANTREX TECHNOLOGY11.2%
SMA AMERICA9.8%
Frequently asked
Quick answers about 94028
How many solar installations are there in 94028?
SolarDNA counts 1,001 active solar installations in Portola Valley 94028, 983 of them residential, with data through April 20, 2026.
How much does solar cost in 94028?
The median residential system in 94028 cost $5.36 per watt over the trailing twelve months, $1.09/W above the California median.
Is solar growing in 94028?
Recent growth cannot be measured yet for 94028: too few recent installs (data runs through April 20, 2026).
Who installs solar in 94028?
TESLA, COBALT POWER SYSTEMS, SEMPER SOLARIS lead the 172 installers with systems in 94028. The full comp set is above.
Is 94028 a good market for solar sales?
94028 scores 38 out of 100 (Fair, higher than 27% of U.S. zip markets).