The short answer: install year-round but mail Q1 marketing for spring + summer capacity. January-March is the prime marketing window — homeowners are reviewing prior-year utility bills, planning curb-appeal projects, and thinking about next-year ITC. Q1 mailings book surveys for March-April and installs through summer peak production.
The Q1 marketing surge
The single highest-yield mailing window for residential solar is January through March. Three reinforcing dynamics:
- Prior-year utility bills are fresh. Homeowners just received January and February bills reflecting full winter usage at current rates. The pain is acute.
- Spring planning behavior. Households make curb-appeal and home-improvement decisions in Q1 to start work as weather warms.
- ITC awareness peaks during tax season. CPAs file homeowner returns Jan-April and surface the 30% federal credit in conversation. Awareness spikes coincide with mailing reach.
Q1 mailings book site surveys for March-April, contracts for April-May, permits + install through summer for peak production capture.
The year-end ITC urgency window
A secondary marketing window opens in August-October as homeowners realize they need the install completed by December 31 to qualify for the current tax year's ITC. Urgency lifts close rates 15-25% above off-peak windows. The constraint: installs starting after October in northern markets may not complete before December 31 due to weather + permit + interconnection backlogs.
Install season production economics
From the homeowner's perspective, install timing affects year-1 production economics meaningfully:
- Late winter / early spring install: system generates 9-10 months in year 1, capturing full summer peak.
- Summer install: system generates 5-6 months in year 1, partial peak capture.
- Fall install: system generates 1-3 months in year 1, minimal year-1 savings (but full ITC for current tax year if completed pre-12/31).
Both qualify for the same ITC, but year-1 cash savings differ significantly. Solar Launch's customer portal surfaces year-1 vs full-year savings on every render.
Utility interconnection + permit backlogs
Most AHJs and utilities run busiest in summer (June-September). Permit and interconnection timelines extend 50-100% during peak. Mailing in Q1 books permits before the backlog hits; mailing in summer can mean installs that drag into October or November.
The optimal calendar
- January-March: 60-70% of annual marketing budget. Lock spring/summer capacity.
- April-July: 15-25% of budget. Fill last-minute summer capacity + warm-follow D2D.
- August-October: 10-15% of budget. ITC urgency push.
- November-December: 5% of budget. Soft marketing; plan for next year's Q1 surge.
Lock the season with Q1 mailings.
Free account, free rendering, $1 per mailed solar quote. Average $32 in install revenue per $1 spent.
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