This only works if the air is cooler, outside, than the temperature, within your home. Otherwise, pointless ! If your temperature if hotter outside still, it's best to just keep the upper window open, to release the warmer air out your home, into the atmosphere. Having the shady part of the home, operational, like the article mentions, for the cooler air to circulate from the bottom of an opened sashes window & have the top one open too !Plus, have some mirrored aluminium film placed on the windows, with a tiny would be better and blinds or curtains closed, on the sunnier / hotter side of the property!!! xxx Beloud