We venture into our improvisational forays without the benefit of a science background, only our reasoning, deductive brain and willingness to try/fail/learn. Good practices and design DO slip by us some times because they’re counterintuitive or we just don’t know better. Case in point: this simple way to adjust our double-hung windows to make our space cool and use AC less frequently. We tested it and it works.

According to Dr. Gary Hunt, an engineer at Imperial College in London, and an expert in ventilation, most people don’t know how to adjust the classic sash windows designed by Edwardians and Victorians to maximize airflow. According to his research:
The trick to getting the maximum flow of air through the window is to slide the sashes so the window is open equally at the top and bottom…
..The cool external air flushes the warm air out of the room and also cools the walls, floor and ceiling. The cool walls then absorb heat the following day and prevent the internal temperatures from rising as high.
The gist:
When you open your windows, make sure there’s an equal gap at top and bottom to allow cooler air through the lower opening and push warmer air through the top.
LIVE AND LEARN!

via The Telegraph
I think some proofreading is in order for the paragraph subtitled The Gist. I only wish my windows worked this way. It’s a really good tip.
How embarrassing! (And funny…”when you open, you’re widows”…a new meaning altogether). Thank you for the catch. I get seriously blind sometimes.