Why Cost Per Appointment Is the Wrong Number to Compare
Two vendors quote $249 and $400 per appointment. The cheaper one looks like the better deal until you ask what share of those appointments actually becomes an installed system. Cost per appointment measures what you paid for one calendar slot. Cost per install measures what you spent to win one signed, installed job, and in a market where customer acquisition cost is spiking 40% to $0.84 per watt in 2026, that is the only number that tells you anything about margin.
The full formula
Cost per install = appointment price ÷ (show rate × close rate)
The Two Inputs That Actually Move the Number
Sticker price is the easy part. Show rate and close rate are where the real spread lives, and they answer two separate questions. Show rate asks: of the appointments I paid for, how many actually happened? Industry sources cite no-show rates of 30% to 40%, even on paid appointments, which puts a typical show rate somewhere between 60% and 70% for an unprotected vendor. Close rate asks a different question: of the appointments that did happen, how many became a signed, installed system?
On close rate specifically, the sourced numbers vary by what is being measured. SunVoy's appointment-level data shows referral-sourced appointments booking at roughly 80% and closing at 37.5% (a 29.2% net conversion from lead to close), while phone-sourced appointments book at 71% and close at 25% (roughly 17.75% net). AgentZap separately cites an industry lead-to-close benchmark of 8% to 12%, with top performers reaching 15% or higher. Treat the AgentZap figure as directional, moderate confidence, and single-sourced, it is measuring the full lead-to-close funnel including leads that never became appointments at all, which is a different and lower number than the appointment-to-close rates above.
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Book a Solar CallThe Simpler Formula for a No-Show-Never-Billed Model
If your vendor never charges for a no-show in the first place, the show-rate variable drops out of your math entirely, because you are only ever paying for appointments that actually happened. In that case, cost per install simplifies to appointment price divided by close rate alone. That is a meaningfully different, and meaningfully lower, number than the full formula produces for a vendor who bills every booked appointment regardless of outcome.
Worked Example: Three Real 2026 Pricing Models
Here is the formula applied to publicly stated 2026 pricing, using the sourced appointment-level close-rate range of 25% to 37.5% from SunVoy. This is back-of-envelope math built from public price bands, not a guarantee from any vendor.
| Vendor / Model | Price | Est. close rate | Cost per install |
|---|---|---|---|
| RunsForYou (booked appointment, billed regardless of no-show) | $150 to $600/appointment | 25% to 37.5% (appointment-to-close estimate) | ~$400 to $2,400 |
| Omnivortex (guaranteed exclusive appointment) | $400+/appointment | 25% to 37.5% | ~$1,067+ |
| VA Horizon (exclusive, no-show never billed) | $300 setup, then $249/appointment | 25% to 37.5% | ~$664 to $996 once setup is amortized |
All three rows use the simplified formula (price divided by close rate) as a floor estimate. Neither RunsForYou nor Omnivortex publishes a no-show guarantee in writing, so if either vendor bills a booked appointment regardless of attendance, the real full-formula number (price divided by show rate times close rate) runs higher, roughly 43% to 67% higher at the 60% to 70% unprotected show rate cited earlier. VA Horizon's simplified number is the accurate one, not just a floor, because a no-show is never billed in the first place. Close-rate figures are sourced estimates, not vendor guarantees, and your own tracked number should replace them once you have a full sales cycle of data.
Do Not Compare This Directly Against Raw Per-Lead Pricing
A raw lead priced at $15 to $100 looks dramatically cheaper than a $249 appointment, but that comparison skips the labor an appointment vendor is doing for you: calling the homeowner, qualifying intent, and booking a specific time. Applying AgentZap's broader 8% to 12% lead-to-close estimate to a $100 lead produces a cost per install of roughly $833 to $1,250, in the same range as the appointment-based numbers above, but that figure does not include the cost of your own team's time spent turning a cold lead into a kept appointment in the first place. Compare vendors within the same buying model before comparing across models.
A Worksheet You Can Reuse on Any Vendor
- Write down the all-in price per appointment, including setup fees, not just the advertised per-appointment number.
- Confirm in writing whether a no-show is billed. If it is, find out the vendor's real show rate before trusting the price.
- Track your own appointment-to-close rate for at least one full sales cycle rather than borrowing SunVoy's or AgentZap's figures directly.
- Apply the simplified formula (price ÷ close rate) if no-shows are never billed, or the full formula (price ÷ show rate × close rate) if they are.
- Compare the final cost-per-install numbers across vendors, not the sticker prices.
What this means for you
- Cost per appointment tells you what you paid. Cost per install tells you what you actually got. Compare vendors on the second number.
- If a vendor never bills a no-show, the formula simplifies to price divided by close rate alone. If they do bill no-shows, you need the show rate too.
- Treat AgentZap's 8% to 12% lead-to-close figure as directional and single-sourced. It measures a different funnel than SunVoy's appointment-level close rates.
Sources
The external data in this guide 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.
- AgentZap, solar lead statistics
- SunVoy, solar lead sources
- Enervio, how to calculate solar cost per lead
- Wood Mackenzie, US residential solar customer acquisition costs
- Invention Solar, how much do solar leads cost