When two solar quotes land on your kitchen table with different panel brands on them, how do you tell which is the better buy? It feels like you’d need to be an engineer. You don’t — because for a home roof, the panel itself is rarely where quotes really differ in quality. Almost every residential panel today is monocrystalline, so the choice isn’t about exotic technology; it’s about who made the panel and who stands behind it. Here’s a practical checklist for comparing panels across quotes without getting lost in spec sheets.
What to actually compare
Four things tell you most of what you need to know:
- Manufacturer reputation (“Tier 1”). This is a measure of a maker’s scale and financial stability — essentially, how likely they are to still be around in 20 years to honour a warranty. It’s not a direct quality score, but it’s a sensible filter that rules out obscure off-brands you’ve never heard of and may never hear from again.
- The two warranties — and read both. A product warranty covers manufacturing defects; look for 12–25 years. A performance warranty guarantees the panel still produces a minimum share of its original output over time — typically 80–92% of rated output at year 25. A longer, stronger pair signals a maker confident in their product.
- Degradation rate. This is how fast the panel loses output each year. Good panels fade only about 0.3–0.5% a year; premium ones as little as 0.25%. A lower number means more generation in years 15, 20, and 25 — a quiet but real differentiator.
- Local support. A warranty is only as good as the company honouring it. A brand with a genuine New Zealand presence (or a solid local distributor) is far easier to claim against than one that vanishes when you have a problem.
If a quote won’t tell you the panel brand and its warranty terms, that’s an answer in itself.
What not to obsess over
Two things draw far more attention than they deserve:
- A point or two of efficiency. Higher-efficiency panels squeeze more watts from less space, which only really matters if your roof area is tight. If you’ve got the room, a slightly less efficient panel just means one or two more panels for the same output — rarely worth a premium.
- The lowest price per panel. A bargain panel that degrades quickly, or whose warranty can’t be claimed because the brand has disappeared, costs you more across 25 years than a reputable one. Cheapest up front is often dearest over time.
The real lever isn’t the panel at all
Here’s the thing the panel debate obscures: the installer matters more than the panel brand. A great panel poorly mounted, badly wired, or sited in shade will underperform and may fail early; a solid mid-range panel installed well will quietly outlast its warranty. The workmanship — correct mounting, proper wiring, shade-aware layout — has more effect on your real-world output and longevity than the logo on the panel. So when you compare quotes, weigh the installer’s competence and warranties at least as heavily as the panel spec. See how to choose an installer.
The verdict
Choosing panels in New Zealand is less about chemistry than about backing: you’ll almost certainly get monocrystalline, so compare the brand’s reputation, the product and performance warranties, the degradation rate, and the local support — and don’t be seduced by a fraction of a percent of efficiency or the cheapest sticker price. Above all, remember that who installs the panels matters more than which panels they are. Get the brand and warranty solid, the installer right, and the panel decision takes care of itself.
Get a free assessment for a spec matched to your roof and budget.
Sources: Panel warranty and degradation data per industry references and long-term field studies (including US NREL research). Figures vary by panel.