Spring Valley, CA 91978 solar market data
Updated January 28, 2026 By The SolarDNA Data Team
Spring Valley 91978 has 1,135 solar installations at a median installed cost of $4.22/W, recent growth not yet measurable, and a Market Score of 44 — higher than 65% of U.S. zip markets.
Versus California
How 91978 compares with the state
Installed cost
$0.04/W below
state median $4.26/W
Market score
44 vs 53
California scores 53
Share of state installs
0.05%
of 2.3M tracked statewide
Battery attach
5.7%
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
91978 by year
27 installs in the trailing twelve months vs 52 before
Installations by year
Median installed cost, $/W DC by year
Installer comp set
Who installs in 91978
Ranked by systems recorded in this zip
| # | Installer | Installs | 12-mo | Avg kW | $/W |
|---|---|---|---|---|---|
| 1 | SUNPOWER | 165 | 0 | 3.65 | $4.22 |
| 2 | SUNRUN | 155 | 7 | 5.74 | $4.69 |
| 3 | BAKER ELECTRIC SOLAR | 77 | 0 | 19.86 | $4.26 |
| 4 | TESLA | 74 | 1 | 6.38 | $5.12 |
| 5 | SEMPER SOLARIS | 64 | 0 | 5.77 | $4.17 |
| 6 | BRIGHT PLANET SOLAR | 34 | 2 | 5.49 | $4.96 |
| 7 | SOLARTECH ENERGY SYSTEMS | 33 | 0 | 7.17 | $3.68 |
| 8 | STELLAR SOLAR | 21 | 0 | 6.27 | $3.95 |
| 9 | FREEDOM SOLAR POWER TX | 16 | 0 | 6.28 | $4.45 |
| 10 | INFINITY ENERGY | 16 | 0 | 5.87 | $4.70 |
| 11 | SUNGEVITY | 16 | 0 | 6.24 | $4.38 |
| 12 | ASI HEATING AIR | 12 | 0 | 5.39 | $3.30 |
Neighboring zips
The nearest zip markets
By distance between zip centroids
| Zip | Distance | Installs | $/W | Score |
|---|---|---|---|---|
| 91977 Spring Valley | 3.7 km | 6,527 | $4.40 | 39 |
| 91941 La Mesa | 5.7 km | 4,820 | $4.14 | 45 |
| 92019 El Cajon | 6.3 km | 5,676 | $4.09 | 50 |
| 92020 El Cajon | 6.7 km | 5,062 | $4.17 | 54 |
| 91945 Lemon Grove | 6.8 km | 2,658 | $4.49 | 40 |
| 91942 La Mesa | 7.9 km | 3,308 | $4.27 | 46 |
Same city
Other zips in Spring Valley
Equipment
What gets installed in 91978
Share of systems with a recorded brand
Modules
SUNPOWER24.6%
QCELLS NORTH AMERICA15.3%
LG ELECTRONICS11.2%
CSI SOLAR4.7%
SILFAB SOLAR4.4%
Inverters
SOLAREDGE29.7%
ENPHASE ENERGY28.8%
SUNPOWER19.0%
SMA AMERICA5.9%
TESLA2.7%
Frequently asked
Quick answers about 91978
How many solar installations are there in 91978?
SolarDNA counts 1,135 active solar installations in Spring Valley 91978, 1,122 of them residential, with data through January 28, 2026.
How much does solar cost in 91978?
The median residential system in 91978 cost $4.22 per watt over the trailing twelve months, $0.04/W below the California median.
Is solar growing in 91978?
Recent growth cannot be measured yet for 91978: too few recent installs (data runs through January 28, 2026).
Who installs solar in 91978?
SUNPOWER, SUNRUN, BAKER ELECTRIC SOLAR lead the 203 installers with systems in 91978. The full comp set is above.
Is 91978 a good market for solar sales?
91978 scores 44 out of 100 (Good, higher than 65% of U.S. zip markets).