Sustainable Building, Eco Development Techniques

Information resouce site for GREEN sustainable building development

Solar water heating

Solar water heating systems use the sun to warm domestic hot water. Any additional hot water is supplied by the conventional boiler or immersion heater.

How does a solar water heating system work?

Solar panels on your roof collect heat from the sun and use it to warm water which is stored in a hot water cylinder.

A boiler or immersion heater is then able to raise the temperature of the water until it reaches the temperature set by the cylinder's thermostat. (This should be set at 60 degrees centigrade.)

In the UK, solar hot water is quite efficient during the summer months, but even in winter, the system raises the incoming water temperature by several degrees.

Benefits of sustainable solar water heating

  • Water heating throughout the year - the system works all year round, though you'll need to top up the temperature with a boiler or immersion heater during the winter months.
  • Lower gas and electricity bills - Every degree that the water is heated by is free.
  • Reduce your carbon footprint- solar hot water produces no carbon dioxide emissions and is a sustainable, green hot water solution. 
  • Can my home benefit form solar water heating?

    • Do you have a south facing roof? You need a south east to south west facing roof which is not in the shadow of trees, buildings, etc and which is at least 6 sq. metres.
    • Can you fit an exra hot water cylinder or a larger one? The water is warmed by another coil, so you will either have to istall another cylinder or a larger one which can take it.
    • Is your boiler compatible with solar water heating? Combi boilers are not usually suitable, as they don't have a hot water cylinder.  The water is fed from the mains into the boiler which then heats it to the correct temperature. Most conventional boiler and hot water cylinder systems are compatible.
    • Do you need planning permission? Listed buildings will need Listed Building Permission.  In any case, it is always wise to consult your Local Authority prior to installation.

    Cost/Benefit of solar water heating

    At the moment, solar water heating is not very cost efficient as 4 sq.metres of solar water heater panels will cost around £3000 (how?) to install and only save around £700 in energy bills over the 10 year warranty period.

    The cost of systems needs to be radically reduced by the manufacturer before they are economically viable.