What Is Customer Acquisition Cost (CAC)?

The 2025 low was an anomaly, not a trend. The looming expiration of the Section 25D federal tax credit created a demand rush that let installers coast on inbound interest while cutting marketing spend, and that cushion disappeared once the credit actually expired on January 1, 2026. On a dollar basis, documented CAC benchmarks put a typical solar sale at $800 to $2,500 in acquisition spend on a roughly $25,000 job.

CAC is not rising evenly across acquisition channels. Outsourced 1099 dealer networks are absorbing the largest 2026 margin compression of any channel, while installers bringing acquisition in-house, through direct paid search, referral, or a controlled outbound program, are preserving more margin per watt as the market tightens. This is the structural reason a fixed, budgetable per-appointment price is getting more attractive relative to an ad-spend-funded or commission-funded acquisition stack whose cost is actively rising underneath it.

None of this is a "solar is booming" story. Residential installs are forecast down 18% to 21% in 2026. Rising CAC in a shrinking market means the companies that control their acquisition cost most tightly are the ones that survive the contraction, not the ones chasing volume.