A solar installer we spoke with had a number in his head: $2,000 a month for ads. It had worked fine in 2024, back when the tax credit was quietly covering a lot of sins.
He was doing a few million a year in revenue, and running the growth of that company on a budget he had not touched in two years.
Then 2026 arrived, the credit went away, and the same $2,000 suddenly produced fewer signed installs at a higher cost each. The budget was not wrong because it was small. It was wrong because it was frozen, aimed at nothing in particular, and measured against the wrong number. Let's fix all three.
How much should a solar company spend on marketing?
Start with a percentage of revenue, not a gut feeling. A common cross-industry rule of thumb puts small-business marketing around 7 to 8 percent of revenue, and home-services and solar companies tend to run higher, often 8 to 12 percent, more if you are pushing hard for growth.
Two honest caveats. First, those are cross-industry ranges, not solar numbers pulled from solar data, so use them as a starting frame, not gospel. Second, they cover everything, not just ads: your website, your follow-up tools, and the media spend together. But the frame does one useful thing immediately. A solar company at 3 million in revenue lands somewhere around 240,000 to 360,000 dollars a year, roughly 20,000 to 30,000 a month across the whole marketing operation. That is the floor to reason from. Now the real question isn't the percentage. It's what each dollar brings back, and in 2026 that dollar buys less than it used to.
Why marketing costs more for solar in 2026
This is the part that breaks old budgets, so it is worth stating plainly.
Wood Mackenzie reports that residential solar customer-acquisition cost jumped about 40 percent, from a five-year low of $0.60 per watt in 2025 to a forecast $0.84 per watt in 2026. The main driver is the end of the 30 percent federal tax credit for customer-owned systems, which expired for systems placed after the end of 2025. For years that subsidy quietly absorbed a lot of expensive lead-buying and dealer-fee habits. With the buffer gone, every wasted lead and every bloated commission now lands straight on the installer.
So a budget set in 2024 is funding 2026 costs. That is the squeeze, and it is why solar customer acquisition cost rising 40 percent this year is not a headline to skim past, it is the reason to rebuild the budget from scratch. The installers who survive this are not the ones who spend the most. They are the ones who know exactly what a signed install costs them, and refuse to overpay for it.
What number should you actually chase?
Not cost per lead. Cost per signed install.
This is the single most expensive mistake we see solar companies make. They shop for cheap leads, celebrate a low cost per lead, and never notice that most of those leads never sign. Reported solar lead prices swing from cheap shared leads to a few hundred dollars for exclusive screened appointments, and booked appointments carry brutal no-show rates, so the price on the invoice tells you almost nothing. Two installers can pay the same per lead, but if one closes a quarter of them and the other closes a twentieth, their real cost is worlds apart. Leads don't pay your crew. Signed installs do.
Cost per signed install (total spend divided by systems actually installed) is the number that survives all the ways cost per lead flatters you. And you have a clean 2026 benchmark to hold it against: Wood Mackenzie's $0.84 per watt. Multiply by your average system size and you have a target cost per install to beat. It also explains why not all solar lead sources are worth the same, once you rank them by close rate: the cheapest source per lead is often the most expensive per install.
How do you set the budget from a revenue goal?
Work backward from the installs you need, not forward from what you're comfortable spending. It's four steps, and you can do it on a napkin.
- Start with the goal. How much revenue do you want to add this year? Say 20 more installs.
- Work back to appointments and leads. If you close, honestly, one in five booked appointments, 20 installs means about 100 appointments. If a third of leads book and show, that is a few hundred leads.
- Price it against cost per install. Whatever it costs to produce a signed install in your market times 20 is your ad budget for that goal.
- Sanity-check it against $0.84 per watt. If your blended cost per install is far above that 2026 benchmark for your system size, you have a funnel problem, not a budget problem.
Do this and the budget stops being a number you flinch at and becomes a number you're buying something specific with. You'll also spot instantly when a channel is underwater: if the cost per signed install is higher than the margin on the install, more spend just loses money faster.
Can your budget be too big, or too small?
Both, and solar companies manage to make each mistake. Here's the shape of it:
| Monthly budget vs revenue | What usually happens | | --- | --- | | Frozen or way under (e.g. 2,000/mo on 3M revenue) | Too little data for the platform to learn; leads trickle; cost per install stays high | | The 8-12% zone, aimed at a real funnel | Platform can learn; cost per install becomes measurable and improvable | | Big budget, broken follow-up | More leads, same leak: you pay 2026 prices to lose faster |
Look at the top and bottom rows: they're the two traps. Starve the budget and the ad platform never gets enough conversions to figure out who your buyers are, so it keeps guessing and your cost per install stays ugly. Flood the budget into a company that doesn't follow up fast, and you simply buy more leads to drop on the floor, now at a 40 percent higher acquisition cost. The middle row is the target: enough spend to let the platform learn, pointed at a funnel that books and shows appointments, judged on cost per install. If your leads come in and sit, book a free audit: more budget won't fix a follow-up leak, and we'll show you which one you have.
What good looks like when spend meets a real funnel
The point of all this isn't a bigger budget. It's spend that lands on a funnel built to close, so every dollar is traceable to an install. And it is why ads alone, with no funnel behind them, keep disappointing: ads without a system are just a faster way to spend the money.
A med spa we work with in Nice put about 620 euros of ad spend through a tight funnel (clear offer, matched page, instant follow-up) and turned it into 193 leads at 3.21 euros each, and 88 paying clients, with the first lead answered 1h27 after launch. That is a different industry with a shorter sales cycle and a much smaller ticket than a solar install, so the raw numbers won't copy across, and we flag it as cross-industry on purpose. But the machine does transfer: right budget, aimed at a funnel that follows up fast, measured on cost per booked, showed, signed job. In a year where every lead costs 40 percent more, that discipline is the difference between growth and quietly going backward.
30-Second Audit
Three yes/no questions about your solar marketing budget. Answer them before you set next month's number.
- Is your budget set from a revenue goal and cost per signed install, not a number you froze two years ago?
- Do you track cost per install against a real benchmark like $0.84 per watt, instead of celebrating cheap leads?
- Is your spend enough for the platform to learn, aimed at a funnel that follows up in minutes and confirms appointments?
If any answer was no, book a free audit: we'll pull your numbers and tell you exactly what's broken, even if you don't end up working with us.
Budget by revenue. Judge by installs. In 2026, measure both twice.