Tip number 155: Create a through-draught

If your house gets too hot in the summer, plan to open selective
windows and doors to create a through-draught - for example, opening
the front and the back doors can be an efficient way to keep the house
cool. This will help keep it cool inside even when it's hot outside.
It's even worth building a new window into a room, but make sure it's
double glazed.

You can find additional information on home ventilation at http://www.smarterhomes.org.nz/design/ventilation/