Introduction to solar heat and hot water 


Solar water heating (known as solar thermal) systems capture the free heat from the sun and use it to heat up water for use in the home. It’s a simple process:

• panels on your roof absorb heat from the sun – they are known as the collector
• the water in the panels heats up
• this hot water is pumped through a coil in your cylinder
• which transfers the heat to the water in the cylinder

Is solar thermal suitable for my home?

The ideal situation for solar panels is facing due south, although they are effective facing anywhere between south east and south west. As a rule of thumb you need between 1 and 2 m2 of collector (solar panels) per person living in the house. Shade on the panels at any time of day will reduce the performance.

Most panels are mounted on a roof, but they can also be mounted at ground level. It is important that they get direct sunlight. To get the best results they should be at an angle between 20 and 50 degrees from horizontal (most pitched roofs fall within this bracket).

If you have an electric shower it won’t use your solar hot water. Similarly cold-fill dishwashers and / or washing machines heat the water they use. In this situation, solar water heating is not suitable unless you use the bath for most of your washing and bathing, as you won't be able to use much of the solar hot water you generate.

Solar panels are compatible with most existing hot water systems. However, you will need a new cylinder with two coils. Ideally it should be big enough to hold two days worth of hot water. 

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How it Works...