What does “gross area” mean in the SOLAR KEYMARK certification?
Edited
The words “gross area” from SOLAR KEYMARK is referring to the entire area of the solar panel.
Until 2016, the reference for SOLAR KEYMARK certification was based on the aperture area but nowadays the reference is on the entire area of the solar panel.
Why?
Because the definition of the aperture area for PV/T was unclear: thermal heat exchanger surface? surface without the frame? ... whereas there is no doubt on the definition of the entire area of the solar panel.