Defaults come from NLR TMY weather (coldest hour, hottest modeled cell). Code calculations (NEC 690.7) use the ASHRAE extreme annual minimum, which is usually colder — enter it above. β is the CEC-measured coefficient; NEC 690.7 calculations use the datasheet value.
Microinverter tables are not shown for panels under 200 W.
SolarEdge and other optimizer-based systems size strings by the optimizer rules — use the manufacturer’s designer. Reference inverters: most named in SoCal permits since Oct 2024.
Expected production in Southern California
NLR PVWatts v8 · Cali-Graf calculation
City
kWh / kW / yr
kWh / panel / yr
kWh / system / yr
Sun, kWh/m²/day
Los Angeles
1,676
260
7,793
6.08
Palmdale
1,835
284
8,533
6.69
Chula Vista
1,696
263
7,886
6.11
Huntington Beach
1,643
255
7,640
5.89
Riverside
1,696
263
7,886
6.21
Santa Clarita
1,724
267
8,017
6.28
Estimate for comparison, not a quote: shading, roof orientation and local losses change real output. Roof mount, 20° tilt, south, 14% system losses.
Questions & answers
How efficient is the Merlin Solar Technologies FXS 155L-W?
Calculated from the panel area (1.11 m²): about 14% for the 155 W class. 155 W over 1.11 m² equals about 140 W per square meter.
How much energy does one panel produce in Los Angeles or Palmdale?
PVWatts v8 with typical-year weather gives about 260 kWh per year per 155 W panel in Los Angeles and about 284 kWh in Palmdale (20° roof, facing south, 14% system losses).
How much power does it lose on a hot roof?
With γ = −0.399 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 20.7% below the STC rating.
Sources
California Energy Commission — Solar Equipment Lists, PV Module List (snapshot Oct 7, 2026).
RETC — PV Module Index report.
NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Chula Vista, Huntington Beach, Riverside, Santa Clarita.
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).
Get your free estimate
Three fields, and Cali Energy calls back within 30 minutes during business hours.
Thanks!
We got your request and will call back within 30 minutes during business hours.