[Mariner]

I get your point.

But the temp of the air leaving the exchanger is sometimes less than even 150F.

And it’s total time in the ducts is unlikely to exceed 3 secs, after which it mixes with 68F room air.

[mrsmith]

Fine.
Yeah, I do wish I could find a study on brief high temp exposure. Maybe tomorrow...
Obvious, IMO, that some exposure to high temps hurts the virus more than no exposure at all. Like in China.