
1) Breeze-maker on a sill 2) Cooling technology
Found on
https://www.crosswordclues.com/clue/window-fan

A window fan is a fan designed to be placed inside the frame of a window. Window fans have been used for many decades to maintain comfortable temperatures and ventilation within one`s home, and operate at a tiny fraction of the cost of central air conditioning. ==Design and operation== Window fans are designed to fit into open windows, and often ....
Found on
http://en.wikipedia.org/wiki/Window_fan

Window fans use little energy and can provide effective cooling in many climates. Window fans are best used in windows facing away from the prevailing wind and exhausting hot air from your home. To cool as much of your home as possible, tightly close windows near the fan and open windows in rooms fa...
Found on
http://www.daviddarling.info/encyclopedia/W/AE_window_fan.html
No exact match found.