The Warranty Gap That Makes an Old System a Real Opportunity
Standard string inverters from SolarEdge, Fronius, and SMA typically carry only a 10 to 12-year warranty, against a 25-year warranty on the panels sitting above them. That leaves a stretch of 13-plus years where the inverter is running unprotected, and a failed string inverter typically costs $1,500 to $3,000 to replace once that warranty has lapsed. A system installed in the early-to-mid 2010s is now sitting inside or approaching that exposure window, which makes a repowering conversation a legitimate, mechanically grounded pitch rather than a manufactured upsell.
The Second Reason: Today’s Panels Simply Outperform a Decade-Old Roof
Residential solar panel efficiency has climbed from roughly 15% a decade ago to a typical 20% to 23% in 2026. That is a second, independent reason an aging system is worth a real conversation: the homeowner is not just facing inverter failure risk, they are also running meaningfully lower wattage per square foot of roof than what is available today. Neither fact alone requires the other to be true, and together they make the pitch stronger than either would on its own.
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Book a Solar CallThe Repowering Segment Inside a Contracting First-Install Market
Residential solar’s first-install market is forecast to contract 18% to 21% in 2026, and customer acquisition cost is projected to spike 40% to $0.84 per watt in the same year. A repowering conversation draws from a population that behaves differently: it is not competing for the same shrinking pool of first-time buyers, it grows every year another system crosses out of its inverter warranty window, independent of what happens to new-construction or first-install demand.
Framing the Conversation Without Sounding Like a Scare Tactic
The honest version of this pitch leads with the specific mechanism, not urgency. A homeowner whose installer is still in business and whose system is inside its inverter warranty does not need a repowering pitch. One whose system is 10 to 15 years old, running a string inverter, and outside that 10 to 12-year window has a real, checkable reason to have the conversation. It is also worth remembering that the workmanship warranty on that original install, separate from the manufacturer’s panel and inverter warranties, was always the installer’s own obligation, which matters directly if that original installer is one of the companies that has since gone bankrupt, covered in more depth in the guide on selling to solar orphans.
Identifying which specific homeowners actually fit this profile, by installation year and inverter type, is its own methodology, covered separately in the guide on identifying repowering candidates.
What this means for you
- Standard string inverters (SolarEdge, Fronius, SMA) typically carry only a 10 to 12-year warranty against a 25-year panel warranty, leaving 13-plus years of out-of-pocket exposure.
- A failed string inverter typically costs $1,500 to $3,000 to replace once the warranty has lapsed.
- Residential panel efficiency has climbed from roughly 15% a decade ago to 20% to 23% typical in 2026, a second reason an aging system is worth a real conversation.
- This segment grows every year, independent of the 18% to 21% contraction forecast for the first-install market in 2026.
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.
- GreenLancer, solar inverter warranty guide
- GreenLancer, latest solar panel technology 2026 trends and innovation
- SEIA, Q2 2026 Solar Market Insight Report
- Wood Mackenzie, 2026 residential solar CAC outlook