SunPower Maxeon — historically the gold standard. 23%+ efficiency. 40-year product warranty (yes, 40). Made in Malaysia/Mexico. Roughly 35–45% more expensive than mainstream Tier 1.
REC Alpha Pure — Norwegian-designed, Singapore-manufactured. Excellent shading tolerance from half-cell design. 25-year product + 25-year power warranty. Around 30% premium.
AIKO Comet (n-type) — newer entrant, 23%+ efficiency, all-black aesthetic. 25-year warranties. Around 20–30% premium. Becoming a Thermova favourite where aesthetics and small roofs matter.
Maxeon (formerly SunPower’s residential line) — same Maxeon cell technology, recently restructured. Strong but trade-press has noted slower service responses post-restructure.
Tier 1 mainstream (Thermova’s default — best value)
These brands deliver 95–97% of premium performance at 70–75% of premium prices. For most Lancashire properties, this is the sweet spot — and what Thermova installs by default unless the customer specifically asks for premium.
JA Solar — Chinese Tier 1 giant, 21–22% efficiency, 25-year power + 12-year product warranty. Excellent track record in UK installations. Often Thermova’s default for value installs.
LONGi — the world’s largest panel manufacturer by volume. Solid, reliable, generally 21–22% efficient. Hi-MO 6/7 series have been excellent on UK installs.
Q Cells (Hanwha Q Cells) — Korean-owned, German-engineered. Strong Lancashire presence. 21–22% efficient. 25-year warranty. Slightly more expensive than JA/LONGi.
Trina Solar — Tier 1, similar spec, similar pricing. The “Vertex S+” monocrystalline range has performed well on UK installs.
Canadian Solar — Tier 1, slightly cheaper than the above. Decent panels but warranty support sometimes slower than Q Cells or JA Solar.
Tier 2 / budget (Thermova generally avoids)
There are dozens of budget panel brands in the UK market — often £600–£1,200 cheaper across a typical install. The savings rarely justify the risks. Common problems:
Shorter or unclear warranties (or warranties tied to UK importer rather than manufacturer)
Higher degradation rates — output dropping below specification within 10 years
Smaller UK service networks — replacement panels take months, not weeks
Tier 1 status that comes and goes — Tier ratings are quarterly and budget brands sometimes lose status
Thermova will quote budget panels if a customer specifically requests them, but flags the trade-offs explicitly. For a 25-year asset on your roof, the savings are usually not worth the lifetime risk.
Solar inverters: the under-appreciated component
Most homeowners obsess over panels and ignore the inverter. This is backwards. The inverter is the brain of the system, the most likely component to fail in years 8–15, and the difference between an installation that runs smoothly for 25 years and one that frustrates the homeowner every winter.
Hybrid inverters with battery integration (Thermova’s default)
These manage solar + battery + grid + (sometimes) EV charger from one unit. Cheaper and simpler than separate solar + battery + charger inverters.
Fox ESS is Thermova’s default hybrid inverter in 2026. Strong all-rounder, competitive on price, robust hardware, with a UK office and support network. Well suited to most single-phase Lancashire installs.
Solis (Ginlong) — Reliable hybrid range, capable app, common in budget-conscious installs.
Sunsynk — Growing fast, strong battery flexibility, good for larger or 3-phase installs.
Premium / specialist inverters
SolarEdge — per-panel optimisation. Every panel reports independently and is managed individually. Best choice for heavily shaded roofs or complex multi-pitch installs. Adds £800–£1,400 to install cost. Excellent monitoring.
Enphase microinverters — each panel has its own inverter. Maximum redundancy, best shading tolerance, longest warranty (25 years). Most expensive option. Best for complex roofs, future panel additions, or maximum-reliability obsessives.
SMA — German engineering, premium pricing, exceptional reliability. String inverters only (no UK-residential hybrid range). Less popular in 2026 because battery integration usually wants a hybrid inverter.
Inverters Thermova avoids
Without naming and shaming, some inverter brands in the UK market suffer from poor app stability, slow firmware updates, weak after-sales, or have been subject to multiple service recalls in the last 3 years. If a quote you’re comparing names an inverter brand Thermova doesn’t install, ask the installer for their failure-rate data and 5-year service history with that brand.
Solar batteries: the brand that matters most
Of the three components (panels, inverter, battery), the battery is the most differentiated by brand in 2026. Different chemistries, different warranties, different lifetimes, very different user experiences.
Premium / flagship batteries
Tesla Powerwall 3 — 13.5 kWh, integrated inverter, 10-year warranty, slick app, market-leading aesthetics. Around £8,500–£9,500 fitted in 2026. The premium choice — and Thermova installs it where customers want the brand and the simplicity.
Sigenergy SigenStor — modular stackable LFP batteries, integrated solar+battery+EV in one unit. Newer to UK market but extremely well-engineered. Premium pricing.
Mainstream UK favourites (Thermova’s most-installed)
Fox ESS is Thermova’s most-installed battery brand in 2026. Strong all-rounder, well priced, robust LFP chemistry, capable app, modular sizing to suit most Lancashire homes.
Sunsynk — Excellent flexibility, good app, strong support. Particularly common with off-grid-leaning homeowners.
Modular value batteries
Pylontech — Modular rack-mounted LFP batteries, very common in budget-conscious installs. Reliable but the user experience is more “utilitarian” than premium brands. 10-year warranty.
Dyness — Similar modular approach to Pylontech, sometimes cheaper, slightly less polished.
Battery chemistry: LFP vs NMC (a quick honest summary)
Almost every battery Thermova installs in 2026 is LFP (Lithium Iron Phosphate) chemistry. The reasons:
Safer — thermal-runaway risk is dramatically lower than NMC
Longer cycle life — 6,000+ cycles vs ~3,500 for NMC
Stable across temperature — works in unheated garages and utility rooms
If a quote you’re comparing specifies an NMC battery, ask why. There can be valid reasons (smaller form factor for tight spaces, slightly higher energy density) but LFP is the default for almost all UK domestic installs in 2026.
The Thermova default install spec (2026)
Unless the customer specifically asks for premium or budget, here’s what Thermova quotes by default for a typical Lancashire home in 2026 — and why:
Panels
JA Solar Mono PERC or LONGi Hi-MO 6 — both Tier 1, 21.5%+ efficiency, 25-year warranty, mid-market pricing
Inverter
Fox ESS hybrid. UK office support, integrated battery management, robust hardware, strong track record
Battery
Fox ESS modular LFP. Modular sizing, robust LFP chemistry, UK office support, 10-year warranty, 6,000-cycle life
Monitoring
Manufacturer app and web portal. Real-time generation, consumption, battery state, grid flow
Mounting
Stainless rails, EPDM gaskets, mid-clamps for tile or slate roofs
Bird mesh
Quoted as standard for properties with pigeon history (Fylde Coast in particular)
This package gives 95–97% of premium performance at 70–75% of premium price. For customers who specifically want SunPower / REC / Tesla / AIKO, Thermova quotes those happily too — but the default above is what we’d install on our own homes.