We're approaching winter, and even though we have the occasional warm days - our pool-water stays insanely cold, so I'm afraid that the days of relaxing at the pool is over... unless of course you were smart enough to install some kind of heating device!

Friends of mine have installed a heating system consisting of fine black tubing that's carefully layed to cover several square meters of their roof. The sun heats the black tubing as the swimming pool pump forces water through the thin, warm, pipes. I believe that it's able to heat the pool by up to 10°C - which makes their winter-water about the same temperature as my pool's summer water!