When do warehouse solar inverters need replacing?
Commercial PV inverter expected service life: string inverters (SMA, SolarEdge, Fronius, Sungrow) 10-15 years; central inverters (ABB, Schneider, Ingeteam) 15-20 years. Signs an inverter needs replacement: more than 3 faults per year on the same unit; PR declining below 75% despite clean panels and no shading; permanent error codes unresolved by firmware update; electrolytic capacitor failure (buzzing, physical bulging); manufacturer end-of-life announcement (software updates discontinued). 2026 replacement alert: string inverters installed 2010-2014 are now 12-16 years old — entering the active replacement window. We recommend a formal inverter condition assessment for all systems over 10 years old.
Like-for-like vs upgrade — the decision framework
Like-for-like replacement is appropriate when: DC wiring and panel configuration is in good condition; system under 1 MW and string architecture remains optimal; budget is constrained. Upgrade is appropriate when: replacing central inverter with string inverters provides better fault isolation; adding SolarEdge optimisers improves partial shading performance on complex roofs; planning to add battery storage in 2-3 years (battery-ready inverter now saves integration costs later); monitoring platform improvement is a business priority (newer inverters: better API, half-hourly data, fault code granularity). Upgrade cost: typically 20-40% more than like-for-like. Generation improvement: 3-8% from better MPPT and lower standby losses. Upgrade pays back through additional generation in 5-8 years.
SolarEdge vs Huawei FusionSolar vs SMA Sunny Tripower 2026
Three dominant platforms for commercial warehouse inverter replacement 2026: (1) SolarEdge (with optimisers): best panel-level monitoring granularity; 25-year DC optimiser warranty; excellent on partial shading/complex roofs; higher upfront cost (optimisers add £50-80/panel); UK commercial market share ~35%. (2) Huawei FusionSolar: best monitoring platform (FusionSolar app — most praised commercial monitoring interface in UK); smart string inverter with AFCI; competitive pricing; UK market share ~30%. (3) SMA Sunny Tripower: 25-year track record; broadest UK service network; Sunny Portal monitoring (good but less intuitive); competitive 25-50 kW unit pricing; UK market share ~20%. G99 re-notification: required when replacing inverters above 250 kW total capacity (G99 Change of Technology notice to DNO). Under 250 kW: G98 re-notification only.
Inverter replacement costs 2026
Commercial warehouse inverter replacement (supply + installation, excluding scaffolding): 25 kW string inverter: £3,500-£5,500 like-for-like; £5,500-£8,000 upgrade to SolarEdge or Huawei. 60 kW string inverter: £7,500-£11,000 like-for-like; £12,000-£18,000 upgrade. 100 kW string inverter: £12,000-£18,000 like-for-like; £18,000-£28,000 upgrade with optimisers. For a 500 kW warehouse system (5 × 100 kW string inverters): like-for-like total £60,000-£90,000; upgrade to Huawei with new monitoring £75,000-£120,000. Capital allowances: inverter replacement qualifies for 100% AIA — reduces net cost by 25% for profitable companies. Battery upgrade path: replacing standard inverters with hybrid inverters now (Huawei Luna 2000, SolarEdge StorEdge) — even without batteries — saves 30-50% on future battery integration versus retrofitting later.
Common questions
Do I need a new G99 application when replacing a warehouse solar inverter?
G99 Change of Technology notification is required if the replacement changes system technical parameters materially (different kW rating, different technology type, change from central to string). Like-for-like replacement (same kW, same type): G99 CoT notification only (4-6 weeks). Systems under 250 kW total: G98 re-notification only. We manage G99 CoT notifications — included in our inverter replacement service.
Can I add battery storage when replacing my inverters?
Yes — inverter replacement is the ideal time to upgrade to a battery-hybrid inverter (Huawei Luna 2000, SolarEdge StorEdge, SMA Sunny Island). Upgrading to hybrid inverters now, even without batteries, saves 30-50% on future integration versus retrofitting later. We assess battery viability alongside every inverter replacement enquiry.