I think the window shades in the PAX cabin work.
The FAs at the previous operator swore that opening the overhead gaspers from PSU all down the cabin helped too, not sure about the technical basis for that. But happy to take their word for it, especially on the external air con unit is seemed to work.
That's apart from the obvious... well, one small thing:
The jetty-mounted conditioners have a control box for the operator. Now, the one at the old home base had two green push-buttons that got me curious. Labelled "NB" and "WB". There is empirical evidence, on the sh-jet when nobody was looking, hitting the "WB" mode increased the noise and cold wind markedly.
