Solar Heating Installations Solent Solar Solar heating array
What is Solar Hot Water (SHW) technology?

Active solar Heating technology means using radiation for heating hot water. In this way, the abundant free energy from the sun can be harnessed to meet a large part of the domestic hot water demand, and reduce the consumption of conventional fuels. The use of these fuels is now widely recognised as causing climate change, and pollution.

The UK receives a vast amount of solar energy which on average equals 60-65% of the annual amount received on the equator. The available range of high quality products enables householders to make effective use of the sun. Thus, even in spring and autumn, and on clear, but cold winter days, the solar hot water system can prove useful.

The principle system omponents are solar collectors, a pre-heat cylinder (optional) pump, controls, connecting pipes, the normal hot water cylinder (or a replacement dual coil cylinder) and a conventional heat source.

How does a typical system work?

The principle is straight forward. When the sun is shining, water is pumped through the solar array, and is heated by solar energy. This heated water then flows through a heat exchanger, or cylinder coil, warming the water stored within the hot water cylinder. If necessary, a boiler or other external heating source provides top up heating. In addition, standard type immersion heaters may be employed.

An electronic controller constantly compares the temperature of the solar collectors with the temperature at the lower end of the hot water cylinder. Whenever the array is hotter than the cylinder (by about 3 deg.C) the controller will switch on the circulating pump/ A mixture of water/antifreeze solution is then circulated through the array and the cylinders heat exchange, heating the cylinder in the same way as a central heating boiler.

What are the benefits of an individual domestic hot water system?
  • Provides you with your own clean source of hot water that also helps reduce global warming.
  • Reduces energy bills, since sunshine is free. Can, in certain circumatances, increase the value of a property
  • Extremely low maintenance, with a long service lifetime of 20-30 years.
  • Silent in operation, and visually unobtrusive.
  • Increase awareness of energy use, and encourages more energy efficient behaviour
What is the energy contribution of an SHW system?

For a family of 3-4, a well designed Solar Hot Water system should contribute between 1,500k Wh and 2,000k Wh, which would normally be the equivalent to 40 to 50% of the household's water heating energy needs. The value of this saving will depend upon the type of energy displaced (natural gas, electricity, etc).


In the summer the water in the cylinder can reach a temperature of 80 deg C within half a day, and good quality insulation on the cylinder will keep the water warm for the next day. Typically a solar hot water system will reduce domestic hot water costs by around 45-60%.

Unit 1, Wooton Business Park
Whiterails Road, Wootton
Isle of Wight, PO33 4RH
Phone:  01983 526427

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