Jeff Thies wrote:

Typar is cheap, about 10 cent/ft^2 IIRC... For 32 cfm, we might poke
0.59" holes, or 0.29" pencil-sized holes with 0.04 "Hg.

What's wrong with felt or multiple layers of black screen (could be
fiberglass). Seems to me that you don't want much distance between
holes. Surely the thermal conductivity of Typar is not that great.

The tiny airflow (32 cfm for an 8'x40' wall) just provides insulation,
eliminating convection heat loss from the mesh to the glazing, as in
a Scandinavian breathing wall. The fin tubes collect the heat, which
moves from the south to the north side of the Typar by conduction and
up to the fin tubes by convection.

Nick