Minimise Hot Water Heating

In many houses there is a large hot water tank which stores the water - heated by the central heating boiler or by electricity.  These boilers are traditionally sized to ensure there is always hot water "on tap" in a family home where the dishes are washed in the sink after every meal and the bath is used every day.  In a modern home where the dishes are washed in a cold-fill dish washer and the shower is used in preference to the bath, the tank volume my not be necessary. If you have an instant-heat electric shower you may not even use it for that purpose...

The hot water tank is heated from the bottom and the water is drawn out from the top where the hottest water accumulates.  It may not be appropriate to keep the tank full of hot water all the time.  If you can reduce the run time of the water heater or the boiler cycle which heats the water you may be able to make a significant reduction in power consumption.  

My experience is that a 1/2 hour boiler run provides enough water for a shower - if you routinely shower in the morning running the boiler for this amount of time early in the morning may be all you need.  There is room for experimentation - and every household will be different - but there may be an opportunity to cut consumption this way.

Heating only the water you need just before you need it saves energy (and cost) and avoids keeping water stored "just in case.