If your house has a
hot water tank (not a combi-boiler/direct water heater) then a simple tip is to just set the timer so that the hot water will come on for only an hour or so in the morning and then switch off for the rest of the day.
The water in a well-insulated tank will stay quite hot for the rest of the day and should still be warm enough in the evening to do any washing up, face washing, etc. if required (especially in the summer).
Obviously, if you use too much hot water during the day then it will go cold, but you can adjust the timer accordingly. The idea is to not use energy to keep the tank of water hot when you really don't need it to be hot. It is a shame that we cannot have two temperature settings for the hot water because we really only need very hot water when we have a bath\shower and need more than one tank-full of hot water.
Also, if you do not use a lot of hot water in the morning for a shower or bath, then instead of adjusting the temperature by mixing in some cold water, just turn down the hot water thermostat to reduce the temperature of the water in the hot tank. Try reducing the hot water temperature by 2 deg C each week until you find the lowest temperature that suits your usage and preferences.
In Summer we don't really need really hot water from the sink taps anyway and it seems silly to heat a whole tank of water up for the whole day. The rooms near the hot water tank will be cooler too if it is not on all day.
Most domestic appliances are cold-fill only (because most houses have directly heated hot water and it is considered 'more efficient'), however if you have a tank full of hot\warm water available during the day, it is more efficient to use a hot+cold-fill washing machine or dish washer and make good use of that warm water instead of just letting it cool down slowly during the day.
In the winter, you may need to adjust the timer and thermostat settings again.
