I hope this is not too off topic. I'm having a new Trane hvac unit installed to replace my current system. I've also always considered a whole house fan; seems that people like them and allows the hvac to run less by cooling the attic. I'm curious though, in an upflow or in-attic blower/furnace installation, it would seem 'easy' to install a simple automated damper in the main supply trunk line which would allow the hvac blower in Fan mode to run right out into the attic, thereby pulling cool outside air through the house, into the return, and out into the attic. Am I nuts? why don't people do this? (or do they?) Since wwf's do pretty much what hvac systems are already designed for, it seems logical....
I did a search on whole house fans, but not much came up.
(Disclaimer - clearly I am not a professional!! just looking for professional advice)