Although double-hung windows are quite common in the Boston area, it seems many people do not take full advantage of their features. With proper use, windows can increase comfort, and all but eliminate the need for air conditioning; and on the odd days where lemonade and mind-over-matter won’t cut it, visit a local library or catch a movie.

How can you take full advantage of windows? If you have two, placing a fan in one to blow warm air out during the evening will pull cool air in the other, especially with a closed door. If you have only one window, a window fan with two fans blowing in opposite directions will also pull air through a space. These are rather obvious practices, but there is a no-cost technique particular to double-hung windows: opening the top sash.

If you have but one window, open both the top and bottom sash’s part-way. If you have two windows, you can open the top sash of one and the bottom sash of another. Using the top sash allows for a natural convection current to develop. Since warm air rises, it can more easily flow out of the top sash, while cooler air replaces it from the bottom. If you open only the bottom sash air above the window is caught in a bubble (like a hot air balloon), and will only cool down through dilution as the air in the top and bottom of the room slowly mix.

Storm windows can complicate the procedure of getting windows into the above configurations, but the problem is not insurmountable. You may also be concerned about bugs, since many double-hung windows only contain a single screen. Use the screen to cover the bottom opening. Since bugs naturally fly up to escape windows, any errant insects will be able to easily evacuate your home over the top sash.