Agreed, but it does keep one's feet and legs cool, which is a BIG improvement over the Roadster! Hood up, with the heater on, it is a very effective de-mister.

I'm not sure how the heater box could be made more effective. Half the problem is that air from under the bonnet isn't really separated from the incoming air.
One answer would be to position a new intake for the heater that pulled cold air from outside, but how to do it?

One way perhaps, could be to have a "throttle body intake scoop" on the side of the bonnet with a duct to the heater box. It would look OK.

Of course most of the year the heater is more important than the A/C.

Peter,
66, 2016 Porsche Boxster S
No longer driving Tarka, the 2014 Plus 8...