Its interesting to see what information should to be labelled on a solar collector. (Table 32)
Largely secondary stuff and absolutely nothing about performance.
As the industry presumably had an the main input in this document, why are they so reluctant to provide a yardstick for consumers to see how good their products are. Doesn't it just encourage the cowboys?
And they are quite open about it (page4):
The guide was prepared with the assistance of industry bodies.
The requirements for labelling the panels look odd, to say the least. If it was to inform the customer about the panel's performance, then why indeed not state that clearly? OTOH If it was just so that safety parameters (max stagnation temp, manifold volume, freezing temp of solar fluid) are given to inform the customer / servicing engineer, then why state the irrelevant bits?
Do we have to assume that the cowboys have made it into gov departments

Klaus