Can anyone suggest a contraption that allows a (casement) window to be opened out nice and wide, but stops a child climbing out? I have a 2 year old windowsill climber and terrifying visions of her tumbling out of the upper storey window, but am having to balance the risk of this against boiling the kids alive in their very warm bedroom in this weather. They complain about the noise of fans and can't get to sleep with one on.