Where solar installers lose money: six invisible margin leaks

Any solar installer knows their theoretical margin by heart. They worked it out on the quote: panels, inverters, mounting, cabling, two crew-days of labour, a percentage on top. The number is correct at the moment it is written down.

The margin actually collected six weeks later is almost always lower. What makes that gap hard to close is not its size — it is that it never opens in the same place twice. It spreads out into small losses, each one too small to trigger an alarm, and not one of them appears as a line in any set of accounts.

Here are the six places they hide, in the order a job passes through them, with the arithmetic to size each one against your own business.

1. What does a lead nobody called back cost?

This is the most expensive loss precisely because it is the most invisible: nothing happens. Someone fills in a form, calls on a Friday afternoon, or messages the company’s Facebook page. A number gets written down. On Monday the crew is on a roof in Sousse and nobody calls back. Three weeks later the prospect has signed with a competitor.

No accounting line records that event. The lead never existed in a system, so its disappearance cannot be measured — and what cannot be measured does not get fixed. The question to ask is not "how many leads did we lose", but "how many leads are we unable to count".

That figure is not a loss in the accounting sense — it is revenue that never existed. Which is exactly what makes it easy to ignore for years at a time.

2. How much does stale equipment pricing cost per deal?

The quote goes out carrying the inverter price from the last restock. Since then the exchange rate has moved, the supplier has revised their list, or that exact part is no longer available and you have to move up a tier. The customer signs the original quote. The difference comes out of margin, and there is nothing to discuss: the price was given in writing.

This leak scales with the time between sending the quote and getting it signed. On a three-week sales cycle it is small. On long deals — a commercial client, a shared building, a file waiting on a permit — it can exceed the entire expected margin.

The fix is not to price more cautiously, which loses deals to whoever priced less cautiously. It is two things: a validity period written on every quote, and equipment prices that come from one current source rather than whichever spreadsheet was open at the time.

3. Why does rebuilding a quote three times get expensive?

The customer asks for a variant: what about 12 panels instead of 8? With batteries? Without the breaker, which they will supply themselves? Every variant is a quote rebuilt by hand, usually in the evening, usually by the most senior person in the company.

The direct cost is sales time. The indirect cost is heavier: by the third manual rebuild, a line gets dropped or a quantity is still the one from the previous version. The mistake clears review because the document looks like the two before it, and it surfaces only when the equipment is ordered.

4. What does a wasted site visit really cost?

A crew drives out to fit an installation and finds on arrival that the consumer unit is not up to standard, that roof access needs a lift, or that one mounting part is missing. The day is gone, the fuel is spent, and the job has to be rescheduled — which pushes back everything behind it.

The real cost is not the lost day. It is the cascade: the next job slips by a week, that customer calls to complain, and someone spends an hour managing a grievance that had no reason to exist.

• Count, over the last three months, how many jobs had to be rebooked after a crew had already travelled.
• Multiply by the true cost of a crew-day — loaded wages, vehicle, fuel.
• Add, for each one, the delay it forced onto the jobs behind it.
• The total is almost always higher than the company would have guessed from memory.

These trips have one thing in common: the missing information already existed somewhere. In a photo taken during the survey, in a WhatsApp thread with the customer, in the head of the salesperson who won the job. It just was not attached to the job.

5. What is phantom stock, and what does it cost?

The spreadsheet says twelve microinverters are left. The warehouse holds seven: five went out on a job last week and nobody recorded it. Sales quotes an installation against the twelve, the supplier order goes in too late, and the fit is pushed back ten days.

That delay has a direct cost — an unhappy customer, sometimes a discount to settle them — and a cash cost: the final invoice lands ten days later, in a business where the equipment was already paid for upstream.

The opposite error costs just as much, more quietly. Stock nobody trusts leads to ordering "just to be safe". Capital sits in the warehouse, in panels from a generation that will be superseded in eighteen months.

6. Why does warranty work show up nowhere in the accounts?

A customer calls two years after the fit: output has dropped. A technician drives out, diagnoses a failed optimiser, replaces it under warranty. The visit generates no invoice, so it leaves no trace in the company’s numbers. It still consumed half a technician-day and a round trip.

Taken one at a time, these visits are the normal cost of the trade. Accumulated across an installed base that grows every year, they become a structural cost nobody has ever quantified — because it shows up nowhere. A company five years into installing can be spending several technician-days a month on warranty work without ever having measured it.

That number has a direct commercial consequence: it tells you what an extra year of warranty, thrown in to win a deal, actually costs you.

Which numbers tell you which leak is costing you most?

None of these six leaks closes until it is measured. Four numbers are enough to tell you which one is costing you most — and they can be reconstructed in half a day, even by hand.

1. 1The median time between an inbound enquiry and the first call back. Not the mean: the median, which two instant call-backs cannot flatter.
2. 2The share of sent quotes that ever get chased. An unchased quote is an abandoned quote.
3. 3The number of jobs rebooked after a crew had already travelled, over three months.
4. 4The number of technician half-days spent on unbilled service work last quarter.

If one of those four is impossible to establish, that is not a methodology problem: that is the diagnosis. Information that was never recorded cannot be analysed, and the leak underneath it will keep running for exactly as long as it stays invisible.