Enphase dominates microinverters. SolarEdge and Fox ESS lead string and hybrid inverters. Here's what the choice actually means for a UK home.
How each technology works
String inverters connect panels in series. DC power flows to a central unit that converts to AC. The fundamental limitation: the string performs at the level of its weakest panel. Hybrid string inverters (like Fox ESS) add battery management in the same unit.
Microinverters sit on each panel. Each panel operates independently — shading or failure on one has no effect on the rest. Enphase IQ8 series are the leading UK residential microinverters.
The core comparison
| Factor | String (Fox ESS) | Micro (Enphase IQ8) |
|---|---|---|
| Shading tolerance | Low — string-level | High — panel-level |
| Upfront cost | Lower — one central unit | Higher — +£100–150/panel |
| Battery integration | Excellent with hybrid | Limited — separate battery |
| Monitoring | System-level (Levelise Hub) | Panel-level (Enphase app) |
| Failure impact | Central failure = offline | One micro = one panel offline |
| Warranty | Fox ESS: 10 years | Enphase IQ8: 25 years |
| Extra cost (10 panels) | Baseline | + £1,000–£1,500 |
When microinverters win
Microinverters are worth the premium when:
- Significant shading — chimneys, dormers, trees, neighbours casting shadow more than 1–2 hours/day
- Complex orientations — panels across multiple roof planes (e.g. east-west split)
- No battery plans — if you won't add storage, the hybrid advantage disappears and Enphase's 25-year warranty becomes compelling
- Maximum monitoring detail — Enphase shows exactly which panel is underperforming and why
Shading impact example
Unsure which inverter technology suits your roof?
We carry out a shading analysis on every survey and tell you honestly if microinverters would make a material difference.
When string inverters win
For most UK domestic installations, a well-specified hybrid string inverter is the better choice:
- Clean, unshaded south/southwest roof — the performance gap is negligible
- Battery storage planned — hybrid inverters integrate seamlessly
- Cost sensitivity — £1,000–£1,500 saving on a 10-panel system is meaningful
- Simpler system — fewer devices, fewer failure points over 25 years
Alliant's approach
What about SolarEdge optimisers?
SolarEdge offers a middle path: a string inverter combined with panel-level power optimisers (DC-DC converters per panel). Panel-level MPPT recovers most shading losses at a lower cost than full microinverters.
Optimisers typically add £400–£700 to a 10-panel system (vs £1,000–£1,500 for microinverters). For moderate shading, often the most cost-effective compromise.
Frequently asked questions
Do microinverters work with battery storage?
Yes, but less elegantly than hybrid string inverters. Microinverter systems need an AC-coupled battery (e.g. Tesla Powerwall), adding cost. Enphase's own Encharge batteries integrate cleanly but are premium. If storage is planned, a hybrid string inverter is typically simpler and cheaper.
What happens if one panel fails?
With a string inverter, the failed panel reduces string output but others continue. With microinverters, the failed panel drops to zero while all others continue at full output — degradation is proportional to one panel.
Can I add microinverters later to a string system?
No — the technologies aren't interchangeable. Upgrading requires replacing all inverters. If shading later emerges, SolarEdge optimisers can sometimes be retrofitted (compatibility checking required).
