Solar marketing budget:
what to spend per install.

Most budgets start with a number someone liked: 'we'll spend $10,000 a month'. Then the leads arrive, the crews fill up, and the extra leads either wait three weeks or get passed on. In solar that waiting has a price, because the buyer's discount depends on when you install.

Turn it around. Count the installs your crews can do in the next period, take off what's already booked, and fill the gap. That number of installs, divided by how many leads sign, is the number of leads you need. Not more.

Crew numbers have a hard limit. The CER reminded installers in April 2026 that they can claim no more than two installations per day, as a safety measure. A solar and battery job together typically takes a crew most of a day, sometimes more, so plan on what your crews really do, not the cap.

Three numbers decide it. Your margin per install after parts and labour. How many leads become signed installs. And the share of that margin you're willing to spend winning the job, which is a business decision, not a marketing one.

Say your margin on a battery install is $3,500, one lead in five signs, and you'll spend a quarter of the margin to win the job. That's $3,500 x 20% x 25%, or $175 per lead. Those numbers are made up to show the maths. Use your own: the last three months of jobs will tell you more than any industry average.

If a channel costs more than that per lead, it isn't paying, however good the leads look. If it costs much less, you probably have room to spend more there, as long as you have the slots.

Enter your crews, bookings and margin. It counts weekday install days until the next battery step-down and works out the leads and daily budget to fill what's left. The starting numbers are made up.

Expect demand to bunch up before each change. Before 1 May 2026, the CER found households accelerated combined solar and battery installations, and more than 80% of April's small-scale solar installs came with a battery. A December 2026 rush ahead of the drop from 6.8 to 5.7 is a fair bet.

That changes the budget in two ways. Early in the period, spend can rise because each install is worth more to the buyer and easier to sell. Late in the period, once the calendar is full, every extra lead signs for an install after the step-down, at a lower discount, while you're still paying urgency-level prices for the click. That's when to cut spend, not raise it.

The Spend Curve method finds the point where extra budget stops paying. For solar, the curve bends twice: once when the auction gets dear, and again when your crews are full.

Google Ads budgets are averages. On a busy day a campaign might spend up to twice its average daily budget, but over a month it won't charge more than 30.4 times the daily figure. So a $100 daily budget can spend $200 on a Tuesday after a rebate news story, and still stay around $3,040 for the month.

That's useful in a rush, and a trap at the end of one. If you need spend to stop on a date, lower the budget or pause the campaign on that date. Don't rely on the average to do it for you.

Facebook and Instagram budgets need the same discipline. Set an end date on campaigns that quote the current discount, and have the next period's version ready. The Facebook and Instagram page covers the form side.

Stop, or cut hard, when any of these is true. Your next four weeks of installs are booked and new jobs will land after a step-down. Your cost per signed install from a channel is above the share of margin you set. Or your call-backs are slipping past the same day, because more leads will only mean more of them go cold.

Keep the cheap things running when you pause: Google Business Profile posts, review requests after every install, and your rebate page kept current. They cost little and carry you into the next period.