Choosing Solar Design Software for LADWP and SCE Jobs: A Checklist
Most solar software can draw panels on a roof. What decides whether its proposals hold up in Los Angeles is whether it bills the way LADWP and SCE bill: two-month periods and a credit that's never paid out on LADWP, hour-by-hour exports under SCE's Net Billing Tariff, Clean Power Alliance's split bill, the customer's actual SCE plan. After that come shade per panel, fire setbacks under the state code and the City of Los Angeles, equipment that actually works together, a proposal under your name that doesn't promise an expired tax credit, and who sees your customers' data. Test any tool on one LADWP home and one SCE home you know well, and compare its first-year bill with the real one. Here is the checklist, with how Cali-Graf — the free design and proposal app built by Cali Energy, a Los Angeles solar and roofing contractor — answers each question and where its scope ends.
The bill: where most tools go wrong
| Ask | Why it matters in LA | Cali-Graf |
|---|---|---|
| Does it bill LADWP by two-month periods, with tiers by zone? | Solar nets 1:1 inside each period; the zone sets the cheaper tier | Yes — Zone 1 or 2 from LADWP's ZIP list |
| Does the LADWP credit pay only what LADWP lets it pay — and never pay out? | Tools that net every kWh fully show lower bills than LADWP will send | Yes — base rates and the access charge only; Credit carried after year 1 shown |
| Does it model SCE's Net Billing Tariff hour by hour, imports and exports separately? | Under NEM 3.0 the hour decides the bill | Yes — all hours of the year, monthly credit, yearly true-up |
| Does it use the customer's own SCE plan and CARE for the bill today? | The bill today sets the savings | Yes — TOU-D-4-9PM, 5-8PM, PRIME or Domestic, with CARE |
| Does it split Clean Power Alliance bills? | Delivery and generation have separate credits and true-ups | Yes — on the city's default CPA plan |
| Does it fill in hourly usage from monthly bills, and show the uncertainty? | Monthly bills don't say when power is used | Yes — 30 similar homes fitted to the bills, with the spread of modeled outcomes (P20–P80) shown for SCE, or the home's own Green Button file |
| Has the bill engine been checked against real bills? | A forecast is only as good as its check | Yes — LADWP bills recalculated within ±3 cents; most SCE bills to the cent |
The details are in how Cali-Graf models an LADWP bill and SCE Net Billing, hour by hour.
The roof and production
| Ask | Cali-Graf |
|---|---|
| Is pitch measured, and does it say when the measurement is weak? | Measured from Google 3D heights, with a note when the heights are uneven; pitch can be set by hand |
| Is shade calculated for each panel, hour by hour, or a flat percentage? | Per panel from Google's height data; a standard 3% only when shade analysis is turned off |
| Does it apply fire setbacks for the state code and the City of Los Angeles? | CRC R329.6 and LAFD rules, picked by the home's city; 36-inch pathways checked |
| Does it model the exact panel and inverter? | Yes — California Energy Commission models, panel heating, the inverter's efficiency and power limit |
| Does it check panel–inverter–battery compatibility? | Yes, from manufacturers' datasheets, for Enphase IQ8 and Powerwall 3; other models are flagged no data |
Where a remote design is weak — old imagery, small vents, trees — is covered in designing a solar layout on satellite imagery.
The proposal
| Ask | Cali-Graf |
|---|---|
| Is it under your name, not the software's? | Your business card on the cover, every page and the signature line; no software brand |
| Does it subtract the expired 30% federal credit? | No — no federal credit and no rebates in the price, payback or savings |
| Does it state its assumptions? | The rate increase and rate plans are printed under the savings sheet |
| Can you show options side by side? | Copies as Option 2, 3, each with its own PDF |
| Does it carry the notices a California customer must get? | The CSLB right-to-cancel text; the rest of the paperwork is the seller's |
Your data and your customers
| Ask | Cali-Graf |
|---|---|
| Who can see your calculations? | Only you; Cali Energy, which runs Cali-Graf, never uses them to sell its own work and never contacts your customers |
| What happens to a customer's data? | Moving every calculation of the customer to Trash deletes it for good after 30 days |
| What does it cost? | Free, with daily fair-use limits; no trial or card |
More in Cali-Graf privacy for installers.
Where Cali-Graf's scope ends
Cali-Graf is built for residential rooftop solar on LADWP and SCE. Outside that, its public list includes:
- Other utilities — Glendale, Burbank, Pasadena and other city utilities, SDG&E and PG&E: the roof can be designed, but bills aren't calculated.
- Some rates and discounts — LADWP's R-1B time-of-use rate, EZ-SAVE and Lifeline; SCE's FERA, Medical Baseline and the all-electric baseline; non-default CPA plans.
- Other jobs — commercial, multifamily, ground-mount and carports; additions to an existing system.
- Paperwork — permit plan sets, single-line diagrams and string sizing; your own logo and payment schedule.
- Teams — shared accounts, and moving calculations between accounts.
Signing happens on the PDF's signature lines; there's no built-in electronic signature. The full, current list is in the help center's What Cali-Graf doesn't do yet.
Test it on two homes you know
The fastest real test of any tool: take one LADWP customer and one SCE customer whose bills you have, run both, and compare the tool's first-year bill without solar with the bills. If it can't reproduce the bill without solar, its bill with solar is a guess. In Cali-Graf, the first year without solar sits on the savings sheet next to the year with it, so the comparison takes one look.
Put Cali-Graf through this checklist on a home whose bills you have — sign in with Google, free.
Frequently asked
What should solar design software do for LADWP homes?
What should solar software do for SCE NEM 3.0?
How can I test the accuracy of solar proposal software?
Is Cali-Graf free?
What doesn't Cali-Graf do?
Related reading
Sources & methodology
Product facts on this page come from Cali-Graf's own help center and the pages linked below; figures in examples come from the stated inputs. Features, limits and supported utilities change; each was verified October 16, 2026.
- Cali-Graf Help — Supported utilities and areas
- Cali-Graf Help — What Cali-Graf doesn't do yet
- Cali-Graf Help — How accurate are the numbers
- Cali-Graf Help — Why results differ from other software
- Cali-Graf Help — Who can see your calculations
- Cali-Graf Help — Is Cali-Graf free?
- Cali-Graf Help — Equipment compatibility check
- Cali-Graf Help — Fire setbacks on the roof
- LADWP — Net energy metering rates
- CPUC — Net Billing Tariff
- LADBS / LAFD — Requirement No. 96, rooftop PV on one- and two-family dwellings
- California Energy Commission — Solar Equipment Lists
- IRS — Residential Clean Energy Credit
Run the two-home test in Cali-Graf
Take one LADWP and one SCE customer whose bills you have, design both roofs and compare the first-year bill with the real one. Cali-Graf is free, with daily fair-use limits, and is developed by Cali Energy (CSLB #1032379).
Prepared by Cali Energy, October 16, 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St, Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)