The quick verdict
Cold D2D and cold mailings both work, but at very different price points. Direct mail (mailed solar quotes via Solar Launch) runs $250-$500 CAC and is highly scalable. Cold D2D runs $1,200-$2,500 CAC with brutal rep churn. The winning strategy: mail to a neighborhood FIRST, then send reps to the same doors 7-14 days later. Warm-follow-up doors close 2-3× the rate of cold doors and the rep day is half as miserable.
Side-by-side
| Metric | Mailed Solar Quotes | D2D (cold) | D2D (warm follow-up) |
|---|---|---|---|
| Cost per home contacted | $1 | $8-$15 (loaded rep cost / door) | $10-$20 (loaded rep cost / door) |
| Engagement rate | 15-20% scan | 2-5% conversation | 10-20% conversation |
| Deposit conversion | 2-4% of mailings | 0.5-1.5% of cold doors | 2-4% of warm doors |
| Loaded CAC per closed install | $250-$500 | $1,200-$2,500 | $600-$1,200 |
| Scalability | High | Capped by rep count | Capped by mailing volume |
| Rep burnout / churn | None (no reps) | 50%+ annual churn | 20-30% churn (warmer environment) |
Why D2D works (when it works)
- Real-time objection handling. A great rep can answer financing questions, address shading concerns, schedule the site survey on the doorstep.
- Trust signal. Showing up in person beats a cold call from a broker lead.
- Same-block compounding. One closed install on a block generates 2-4 additional close opportunities from neighbors who saw the truck.
Why D2D fails (when it fails)
- Roof viability is invisible from the street. Reps burn time on homes with shaded north-facing roofs that can't qualify.
- Rep skill variance is enormous. Top reps close 4-8 installs/month; bottom reps close 0-1. The average rep underperforms the loaded CAC math.
- Long-cycle nurture is hard. A homeowner who says "let me think about it" needs 3-6 follow-up touches. D2D handoff to a CRM workflow is leaky.
The winning sequence
Mail + warm-follow D2D = lowest combined CAC
- Day 0: Send 500 mailed solar quotes via Solar Launch ($500 total).
- Day 7-14: Postcards land in mailboxes. Homeowners see their roof rendered with solar + projected savings. ~75-100 scans expected. ~10-15 site-survey deposits without any door-knocking.
- Day 10-21: Reps walk the SAME neighborhood door-to-door. Homeowners recognize the company name from the postcard. Conversation density doubles, close rate doubles, rep day is dramatically less miserable.
- Day 21+: Site surveys happen. Homeowners who already saw their savings math on the customer portal close at 60-75% (vs 25-40% on cold leads).
Combined CAC on warm-follow D2D: $400-$700 per closed install — less than half the cold-D2D number.
Make your D2D reps walk warm doors.
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