The 4 things that matter in a solar panel
Forget marketing. Only four spec-sheet numbers actually matter for residential solar:
- Efficiency — % of sunlight converted to electricity. Range: 19% (budget) to 22.8% (premium).
- Year-1 degradation — drop after first year. Premium: ≤2%. Budget: 2.5–3%.
- Annual degradation — drop per year after year 1. Premium: 0.25–0.4%. Budget: 0.5–0.7%.
- Product warranty — covers manufacturing defects. Premium: 25 years. Budget: 12–15 years.
Premium tier (worth it for shaded or small roofs)
These cost $0.20–$0.40 per watt more than budget panels. Worth it only if you have limited roof space or a small system where every panel matters.
- Maxeon (formerly SunPower) — 22.8% efficiency, 0.25% annual degradation, 40-year product warranty. The gold standard, but priciest.
- REC Alpha Pure-RX — 22.6% efficiency, 0.25% degradation, 25-year warranty. Almost matches Maxeon for less money.
- Qcells Q.TRON BLK M-G2+ — 22.5% efficiency, 0.3% degradation, 25-year warranty. Strongest US-made option in the premium tier.
Mid-market tier (best value for most homes)
These are what most reputable installers use. Excellent quality, reasonable price.
- Qcells Q.PEAK DUO BLK ML-G11+ — 21.4% efficiency, 0.5% degradation, 25-year warranty. Most popular panel in the US for good reason.
- Silfab Prime SIL-440 HC+ — 22.1% efficiency, 0.4% degradation, 30-year warranty. North American manufacturing.
- SEG Solar (SEG-NMG / SEG-NDA series) — 21.5–22.0% efficiency, 0.4% degradation, 25-year warranty. Houston-based with US manufacturing in Texas. Strong domestic-content option that's grown rapidly since their US factory ramped up. Often priced below other US-made options, making it a strong value pick when domestic content matters (SREC bonuses, Buy America preferences, tariff hedging).
- Canadian Solar HiKu7 — 21.6% efficiency, 0.45% degradation, 25-year warranty. Reliable workhorse.
- Trina Solar Vertex S+ — 22.3% efficiency, 0.4% degradation, 25-year warranty. Strong specs at competitive price.
Budget tier (only if price is the deciding factor)
These work fine but have shorter warranties and faster degradation. Use only when budget is tight and you have plenty of roof space.
- JA Solar — 20–21% efficiency, 0.55% degradation, 12-year product warranty.
- Jinko Solar — similar specs and warranty to JA Solar.
- Risen Energy — budget pricing, mixed reliability reports.
Why domestic-content panels matter more in 2026
Three reasons US-made panels (Qcells Georgia, Silfab Washington/NY, SEG Texas, Maxeon US plants) became more competitive in 2026:
- Tariffs. 2025 tariff increases on Chinese and Southeast Asian panels narrowed the price gap dramatically. US-made panels are now within $0.05–$0.15/W of imports.
- Domestic content bonuses. Some SREC and state programs offer adders for systems that meet domestic-content thresholds. SEG and Silfab generally hit these thresholds; many imported panels do not.
- Supply chain stability. US manufacturing means shorter lead times, easier warranty claims, and less geopolitical risk.
If your installer offers SEG, Qcells (Georgia-made), or Silfab at a price within $0.10/W of imported alternatives, the US-made option is usually the better choice.
What's the real efficiency difference?
The difference between 21% and 22.5% efficiency sounds dramatic but isn't. On an 8 kW system, it's the difference between 16 panels and 17 panels — about 5% more roof space needed for the budget option. If you have unlimited roof, the value tier wins on cost-per-watt-installed. If your roof is small or shaded, premium efficiency lets you fit more capacity in fewer panels.
Bifacial panels
Bifacial panels capture light on both sides and can produce 5–15% more energy when mounted with proper backside exposure (ground mount, light-colored roof). On standard rooftop installations, the bifacial gain is usually negligible (1–3%). Don't pay extra for bifacial unless you have a ground mount or commercial-style installation.
Is the panel in your bid worth the price?
Upload your solar proposal — the analyzer cross-references your panel against current spec sheets and tells you if you're getting a fair deal for that brand.
Analyze My Bid →Frequently asked questions
Are SunPower panels still available?
Yes, but the brand is now Maxeon (after 2024 restructuring). Maxeon makes the same panels in the same factories. Some legacy SunPower-branded panels are still in distribution.
What about SEG Solar specifically?
SEG is a Houston-based company that opened a Texas manufacturing facility and has scaled rapidly. Their panels offer mid-market specs (21.5–22% efficiency, 25-year warranty) at competitive pricing — and they're domestic-content compliant, which can unlock state SREC adders in some markets.
Are US-made panels worth the premium?
In 2026, often yes. Tariffs narrowed the price gap, domestic content can trigger state bonuses, and US warranty support is faster. Qcells, Silfab, and SEG are all competitive options.
How long do solar panels really last?
30+ years with reduced output. Most panels still produce 80–87% of original after 25 years.
Should I wait for better technology?
No. Solar panel efficiency has plateaued near silicon's theoretical limits. Big leaps (perovskite tandems) are 5+ years from reliable residential availability.