[twawaaay]

I live in a cold climate so maybe less examples on how to keep your house cool and more about how to keep it warm.

I think I have seen a primitive but very effective heat exchanger in an old house. Normally, when you have a stove and chimney and hot gasses escape the house you also have a lot of cold air rushing in. In this house the hot air was directed around the whole length of the chimney and then through the mass of bricks that formed the stove so that the air coming in was already warm.

This allowed to very efficiently keep the entire house very warm while also nicely ventilated even in very, very cold weather with very little wood needed.