Solar water heating

When trying to save power, for most people the quick win is saving on water heating costs. We installed a solar system with two collector panels when the house was built 12 years ago, and they are still working well. For at least half of the year we don't need any extra heating, and in winter we just need to "top-up" the temperature. We use hot water around 6-7 am for showering. The top-up heating is on a timer to come on for an hour in the morning, finishing just before shower time.

The reason the timer switches off the heater before we use water is so that we don't waste power reheating the water when we will not use it for another 12 hours, and there is a good chance the sun will heat it anyway. The rate of heat loss from the cylinder is proportional to its temperature. This way we minimise heat loss. The down side is that water may not be very hot at other times of day.

We also turned the thermostat of our cylinder down to around 45 degrees C, so we don't need to add much cold water to the mix for the shower. Remember, the cooler the water in the cylinder, the less heat loss we will need to replace.

Any other ideas?