Read the 40% Before You React to It
Start with what the number is. Wood Mackenzie’s outlook projects acquisition cost per watt for residential solar, measured against a 2025 low of $0.60 per watt. A percentage jump off a low base looks dramatic, and part of the drama is the base. That does not make the figure comfortable. It means you should read it as one outlook’s projection, not as a price list for your market.
Your own CAC is a blend of lead cost, sales labor, overhead, and the contracts that cancel before install. Compute it that way, per signed watt and per installed watt, split by channel. If referrals close cheaply, or one source’s contracts cancel far more often than another’s, you can respond precisely. A dealer who only knows the industry headline will respond with a blunt instrument.
Why Volume Games Backfire in a Shrinking Market
When cost per signed contract climbs, buying more leads feels like action. In a market SEIA forecasts down 21%, though, more volume usually means shared inventory, aged lists, and homeowners who were never going to buy. Show rates fall, close rates fall, and the crew still drives to every visit. Cost per lead drops. Cost per signed contract rises. The spreadsheet that celebrates the first number hides the second.
The same logic covers the other volume games: relaxing qualification to hit an appointment quota, adding setters to book anyone who will pick up, discounting to hold install counts. Each lifts an activity number and drains margin from the deals that did close. A discount made to protect volume also resets the price floor for every future quote. It is cheap to start and expensive to stop.
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Book a Solar CallFind the Leaks Before Buying More Top of Funnel
Walk the funnel one stage at a time: lead, contact, booked, confirmed, sat, proposal, signed, installed. At each step, write down what is lost and what that loss costs. The cheapest fixes are early and boring: faster first contact on inbound leads, a real confirmation sequence (our show-rate playbook covers one), qualification at booking, and a follow-up cadence for proposals that went quiet. None of them requires buying another lead.
Two leaks deserve a hard look in 2026. Aurora Solar projects third-party ownership (TPO) rising from 44% of reps’ books in 2025 to about 65% in 2026, and lease and PPA deals typically run a credit screen, so a household that fails it becomes a dead sit that carried full acquisition cost and produced no revenue. The other leak is the contract that signs but never installs, which inflates CAC per installed watt. Both stay invisible if you only watch leads and appointments.
Levers That Cut Cost Without Adding Volume
Past customers are usually the cheapest pipeline a company has. A reactivation call to a homeowner with an older system, opening an honest battery or expansion conversation, usually costs far less than buying a new lead. Referrals work when somebody asks at a good moment, such as after the first bill that shows the savings, rather than at signing. Neither scales like paid media, but both lower blended CAC the day they start.
Tighten the paid channels too. Cut the lead sources that miss your cost ceiling in two reviews in a row. Match appointment times to when closers are actually free. Where you can, pay for outcomes: sourcing that bills on booked, confirmed appointments moves the risk of a bad lead off your books. And do not cut confirmation or follow-up to save labor, because that is the cheapest conversion in the building.
A Decision Rule for the Year
Set a ceiling for cost per signed contract by channel, review it monthly, and write down in advance what happens when a channel breaches it twice. Hold more cash than last year, because a market SEIA expects to shrink 21% punishes thin reserves. Keep fixed headcount in top-of-funnel roles modest, since a recovery that SEIA places between 2027 and 2031 may not arrive in time to pay for it.
In our view, the dealers who handle a year like this best know their cost per signed contract by channel and cut any source that keeps missing its ceiling. VA Horizon’s solar appointment setting suits that approach: you pay only for booked appointments, with no retainer, and every one is exclusive and double-confirmed, with no-shows replaced, never billed.
Sources
The external data in this article draws on the sources below. Figures described in the text as estimates or industry triangulations are directional and are not attributed to a single dataset.
- Wood Mackenzie, 2026 residential CAC outlook
- SEIA, Q2 2026 Solar Market Insight Report
- Aurora Solar, 2026 TPO financing trends