# Is it true that a pair of open windows create a strong continuous "draft" wind?

A common belief is that opening two windows or doors inside the home can create a strong and steady flow of air (a "draft") that a single window would not create. This seems somewhat intuitive, yet I have not been able to find a rigorous explanation.

Is this true? If so, how do the mechanics of this work? How does the effect depend on the positioning of the windows relative to each other? Additionally, how is it changed by the addition of more than two open windows?

Are there any other factors?

• It is just the continuity equation for the system. If there is air flowing into the room, the same amount of air has to flow out. Commented Feb 22, 2021 at 17:51
• And on hot days with no breeze don’t count on magically making one by opening two windows. Commented Feb 22, 2021 at 17:54
• Some people have answered how this works if one window is on the upwind side and the other is on the downwind side. As a follow-up, what if the two windows are opposite each other but the line between them is perpendicular to the outdoor windflow? And how about if the windows are in different rooms (with an open door but no straight line of flow)? Can this create any effect?
– bob
Commented Feb 22, 2021 at 20:01