I have a classic brick chimney for a wood fireplace only (i.e. no hot water tank or other things sharing the stack).
In peak summer heat, the interior of the upstairs is well above the exterior temperature in the evenings for many hours.
I am wondering if a box fan pointing up the stack would be effective for pushing air out of the house.
It would be particularly convenient from a security point of view since the chimney is an existing hole in the structure, and "secure". We could even leave it running unattended 24x7.
Is this a bad idea? I'm OK if it's less efficient for some reason than a window or doorway placement. But if it would be completely ineffective, then, that would be a problem.