Solar · 2026-03-27 · 7 min read
Microinverters vs Power Optimisers vs Strings
A decision framework based on roof geometry, not vendor preference.
Why this matters now
Microinverters vs Power Optimisers vs Strings has moved from a specialist concern to a mainstream engineering decision. Tariff structures across Europe increasingly price energy by the hour and by peak demand, which means the way a building consumes energy now matters as much as how much it consumes. This article sets out the engineering fundamentals, the decisions that actually change outcomes, and the mistakes we see most often in the field.
The engineering fundamentals
Start from the load profile, not the product catalogue. A year of hourly consumption data reveals the shape of the problem: where the peaks fall, how much of the annual energy sits in expensive hours, and how much of it could be shifted. Only once that shape is understood does the choice of generation capacity, storage capacity and control strategy become obvious rather than arbitrary.
Specification decisions that change the result
Nameplate capacity is the least interesting number in any specification. Round-trip efficiency, temperature coefficient, degradation curve, continuous versus peak power, protection coordination and control quality determine what the system delivers in year ten. We specify against modelled fifteen-year performance and publish the assumptions.
Common mistakes
Oversizing generation while undersizing storage. Ignoring the connection agreement's export limit. Treating backup as an afterthought and discovering at commissioning that the essential-loads panel cannot start the heat pump. Skipping the earthing survey. Every one of these is cheaper to solve on paper than on site.
What AIRVOLT recommends
Model first, specify second, install third. Instrument everything so that performance can be verified rather than asserted. And design with headroom, because every building we touch will be more electrified in five years than it is today.
Let's engineer your energy system.
Send us a year of electricity bills and a photo of your roof. We return a full engineering proposal with modelled production, savings and payback.