Right, casa Piper is an old house with double-hung sash windows and radiators for heat - i.e., no central air.
So I’ve got widow fans that fit in our sash windows: open window, insert fan unit, lower window onto the fan, plug it in and Bob’s your uncle.
Given the summer heat, it runs a lot, and I’ve noticed something.
If the door to the bedroom is open, the fan is quieter. As soon as I close the door, it gets louder and the sound seems to shift to the bass a bit.
And it’s not just one room. I’ve noticed it in both bedrooms that have fans, and they’re different sizes, floor plans and furniture arrangements.
So how come the change in volume and pitch, just from shutting the door?