There has been research that suggests that washing dishes in hot water is no more hygienic than cold. In order to kill germs it has to be so hot (boiling) you couldn't use it! I usually only use hot water in my shower. Washing up and washing my hands I use cold. This is mostly because we live in a big house and the boiler is so far away it takes about 5 litres of water before it runs hot. It is a waste of water to use hot water! In the shower we have canisters so we can save the water before it runs hot!