All but one major room is part of a single path through home, from a window on one end to a window on the other. In the evening I want to bring in cooler outside air as efficiently as possible. If there is no breeze outside, is it faster to
- close all windows except the two endpoints, setting up the box fan (which fits well in the window) to push air in or pull it out at one end.
- open all the windows, and put the fan somewhere, without knowing exactly what the path of airflow from it will be.
The first method takes no advantage of whatever minimal passive airflow would occur with all windows open wide.
The second method doesn't make as good use of the fan, because it may end up cycling the air immediately around it over and over instead of reaching all areas of the house.
If passive circulation were truly nonexistent, then maximizing the fan's efficiency would be the way to go. Does it seem plausible that passive circulation could indeed be low enough for that to be the case?
Best Answer
Moving air tends to feel cooler than still air. If you can put up with the noise, the box fan trick works quite well.
In my experience, air movement in the home depends on air movement outdoors; if it's a still evening, even with lots of windows open, you won't get much air. On the flip side, even a small breeze can help.
If you have lots of money and live in an amiable climate (cool, dry nights), buying a modern whole-house fan may be a good fit. Modern units suspend the fan itself from the rafters via an insulated duct, and are much quieter than they used to be.
As Jimmy Fix-it commented, the best thing to do is to try both of your methods.