Where the money sits during one residential install
A solar job is a chain of small events, and the cash moves at different moments along it. Roughly, in the order a crew lives it:
- Contract signed. The customer commits, and you pay for design work, permit paperwork and a site visit.
- Equipment ordered. Panels, inverters, racking and wiring leave your account, often before the customer has paid more than a small deposit.
- Install week. Crew payroll, truck fuel and small consumables go out on a weekly cycle.
- Inspection and utility sign-off. The system is on the roof but not yet producing. This is the step that tends to stretch.
- Final payment. The remainder of the contract arrives, sometimes weeks after the last bolt was tightened.
The pressure point is the stretch between step 2 and step 5. Your costs are front-loaded; your revenue is back-loaded.
A worked picture, for illustration only
The table below uses round numbers to show the shape of the float on one hypothetical $30,000 residential job. These are not our terms and not a typical outcome; real contracts, equipment costs and payment schedules vary widely.
| Stage | Cash out | Cash in |
|---|---|---|
| Contract signed | $800 design and permit work | Small deposit |
| Equipment ordered | $13,000 panels, inverter, racking | Nothing yet |
| Install week | $4,500 crew and truck costs | Progress payment, if the contract has one |
| Waiting on inspection and utility | Overhead keeps running | Nothing |
| System approved | Sales commission, warranty reserve | Balance of the contract |
In this sketch, close to $18,000 has left before the main payment arrives. Do that on three jobs at once and the exposure triples, even if every customer pays on time.
Why deposits do not close the gap
California's contractor board says that on home improvement work, a contractor cannot ask for or accept a down payment of more than $1,000 or 10 percent of the contract price, whichever is less, and that other payments must track work actually completed or materials delivered. The board's notice, published in the context of rebuilding after declared disasters, says the rules cover residential solar installations. You can read it on the Contractors State License Board home page.
The practical reading for an installer: the customer's deposit will not pay for the equipment. Your working capital does. On a $30,000 job, 10 percent would be $3,000, but the $1,000 cap would be the lower figure and would control. That is why installers with a full calendar can be short of cash at exactly the moment business looks strongest.
What the San Diego setting adds
San Diego is the second-most populous city in California, with 1,386,932 residents in the 2020 census, and it is the seat of San Diego County, home to 3,298,634 people. Public sources describe it as having a mild Mediterranean climate and extensive beaches and parks, which is a reasonable backdrop for rooftop solar. State policy points the same way: Wikipedia's overview of solar power in California notes the state's renewable portfolio standard, which requires that 60% of California's electricity come from renewable resources by 2030 and 100% by 2045.
That kind of steady demand tends to produce more jobs in the pipeline, which is good for revenue and hard on cash. A crew that books six installs in a month needs six equipment orders, and the utility's sign-off timeline sits outside your control. The state's contractor classifications include a dedicated C-46 solar contractor category, so this is a regulated trade with its own licence track, not a side line.
Panel inventory and interconnection delay are two different problems
Inventory timing. Buying panels in a larger lot can improve your cost per job, but it ties up cash before you have signed customers for them. Buying per job keeps cash free, but exposes you to delays when a particular model is hard to get. Neither is wrong; the right choice depends on how predictable your sales are.
Interconnection delay. Once the system is built, the local utility has to approve it before it can run. If that approval slips, your final payment slips with it while your crew goes on to the next job. Payroll does not wait for the utility.
The two problems stack. A busy month with a utility backlog is the classic squeeze: more equipment purchased, more money still outstanding.
Where funding fits
Working capital from $25,000 to $5,000,000 can bridge the front-loaded stretch of a job cycle. Funding can arrive in as little as 24 hours, FICO scores of 500 and up are considered, and the file centres on about three months of business bank statements. No tax returns are required, the application takes about five minutes, and the credit pull is soft. Sole proprietors can apply.
If you are comparing structures, our pages on equipment financing, business lines of credit and working capital explain how each one handles repayment against a job cycle. For a broader view of the county, see San Diego County business funding.