European Efficiency
SpecificationA single weighted efficiency figure that averages an inverter's efficiency at several load levels, with the weights chosen to reflect a typical Central European irradiance profile. It is always slightly lower than peak efficiency and is the fairer number for comparing models.
The weighting is fixed by convention: 3% of the score comes from efficiency at 5% load, 6% at 10%, 13% at 20%, 10% at 30%, 48% at 50% and 20% at 100%. Half the weight therefore sits at half load, which is where a PV inverter genuinely spends much of its life — full output happens only around solar noon on clear days. A model with a strong European efficiency but an unremarkable peak will usually harvest more energy over a year than the reverse. In sunnier climates the equivalent CEC weighting is sometimes quoted instead.