Turn excess attic heat into hotwater

Senseless writes – “I was wondering if I could heat the water in my swimming pool using the heat in the house’s attic and I started messing about with a large heatsink. The water for my hotwater heater has to pass through it and picks up free calories which saves on the power bill quite a bit of the year. Even on winter days it adds some heat to the water and every calorie free is one I am not paying for…” Link.