Interior vent debris

[particlewave]

There is some misleading info here.
The deteriorated foam absolutely will affect both heat and AC, as James pointed out. The flap in front of the heater core, which is always hot, either makes air blow over the core for heat, or blocks it off. If that flap is full of holes, your AC will partially blow over that hot heater core.

Also, as Tom said, it's nice to keep a clean interior and not be pummeled with foam bits that turn to black tar when you touch them.

[Meir]

Well, I can speak only from my experience.
The Boxster S I had, had a leaking evaporator, so the AC didn’t work regardless, and when I fixed it, I obviusely re-foamed the flaps.
On my 99 box and 02 996, there was/is no foam coming out anymore. So the flaps are naked for sure. I do not see any difference with the AC between the 3 cars. They are all blowing cold. The heater is a different story.
With that said, I do not like penguins temperature in my car, although i leave in FL.
Since I have the Boxster S (with the fixed flaps) and the 996 both in my garage, it will be interesting to preform a comparison between the two, using an infra red thermometer directed to the center AC vent (as described in the shop manual).
Maybe I’ll do it next week when I get back from my road trip.