The comparison in 2026
Two dominant inverter topologies on UK PV systems: string inverters (one central inverter per string of panels) and microinverters (one inverter per panel). For UK farm installs, string inverters dominate — but understanding why microinverters lose helps confirm the design choice.
Detailed comparison
String inverter topology. One central inverter (or multiple central inverters on larger installs) handles the AC conversion for a string of panels. Standard for commercial installs. Cost: typical Huawei SUN2000 100 kW string inverter ~£8,000. Reliability: 15-20 year operational life; one-or-few failure points; manufacturer warranty 10-25 years. Microinverter topology. One small AC inverter per panel; each panel produces AC directly. Costs typically £100-£150 per microinverter. On a 100 kW system with 185 panels: £18,500-£28,000 in microinverters alone — vs £8,000 for the string inverter equivalent. Premium of £10,000-£20,000. Shading tolerance. Microinverters: very good (each panel optimised independently). String inverters: poor for shading (string operates at shaded panel's level). String inverters with optimisers (SolarEdge): comparable to microinverters. UI and diagnostics. Microinverters: panel-level diagnostics. String inverters: string-level. SolarEdge optimisers: panel-level. UK farm context. Most UK farm rooftop installs have: relatively uniform roof slope; predictable shading patterns; large clean roof areas. The shading and complexity advantages of microinverters don't typically apply. Microinverters win when: site has severe complex shading; multiple roof orientations create string mismatch; future expansion planned in stages; aesthetic considerations matter (commercial less relevant). Microinverters lose when: simple roof geometry; cost matters; large system size makes microinverter premium very expensive. Recommendation. For UK farm installs in 2026: string inverters are the standard choice. SolarEdge with optimisers where module-level monitoring matters. Microinverters rarely justified on commercial farm scale.
How to decide for your specific install
The right choice depends on the specifics of your farm: roof geometry; load profile; capital sensitivity; future expansion plans; long-term operational priorities. We model multiple specification scenarios in every feasibility study where the choice is material. Send us your half-hourly meter data and building dimensions — we deliver a free desk feasibility within 7 working days, including specification recommendations with clear rationale.
Common questions
What do you typically recommend?
Depends on the specifics of the site. Our default approach is documented in the comparison above; we model alternative scenarios where the project requirements suggest different specification choices.
How material is the difference in practice?
Most specification differences sit at the margin of project economics — typically 2-10% impact on overall 25-year NPV. The fundamental decision (whether to install PV at all) is far more material than the specification choice within PV.
Can we change specification later?
Some changes possible without complete reinstall (e.g., battery brand, inverter replacement at end of life). Other choices (e.g., optimised tilt vs roof-pitch following) are baked in at install. Specification decisions for permanent elements should be made carefully at design stage.
Do you have a preferred manufacturer or product?
We're independent of any specific manufacturer. Every quote includes specification recommendations specific to the site geometry, the farm's strategic priorities, and current market pricing. We never push a specific brand without rationale.