Which method is more effective (and why) for recirculating air into a room: a) using a fan to blow air out of a window, or b) using a fan to blow air in through the window?

Question

For context, I’ve got a basement room in an old house that isn’t tied in to central air conditioning, and sometimes the air gets a bit stale.

It has a basement window, so I’ll open that up and stick a fan in the window to blow air out, but someone told me that it’s better to have the fan outside and pulling fresh air in.

The room won’t be overpressured as it’s got a big gap under the door, and the fan doesn’t cover the whole window.

In: Physics

Answer 1

I’m going to take a big guess and say blowing OUT is better.

Here’s why.

Two of the homes I’ve lived in, came equipped with what we called a “[whole house fan](https://www.greencat.ninja/sites/default/files/styles/panopoly_image_original/public/lifestyle.jpg)”. It was in an upstairs hallway, mounted in the ceiling of the hallway, and blew into the attic.

If you turn the whole house fan on, it will draw air IN through any windows you have open. We would turn the big fan on, and open the living room windows, and you’d get a strong current coming into the living room.