My homemade air-con unit does the trick | Brief letters

Tips for keeping cool | External shutters | Netting solution | Educational benefits of Octonauts | Southgate’s penaltyFor a cheap and simple air-con unit: take the blue blocks used in most cool bags from the freezer; put them in a metal saucepan (we use a wok); place them in the airflow of a fan. Remember to put them back in the freezer in the morning. Sleep tight!Helen CatonWoodmancote, Gloucestershire• Putting external shutters on windows is a good idea (Letters, 27 May), but windows open outw...