Solar water heaters -- sometimes called solar domestic hot water systems -- can be a cost effective way to generate hot water for your home. They can be used in any climate, and the fuel they use -- sunshine -- is free.

Solar water heating systems, or solar thermal systems, use energy from the sun to warm water for storage in a hot water cylinder or thermal store. Because the amount of available solar energy varies throughout the year, a solar water heating system won’t provide 100% of the hot water required throughout the year. A conventional boiler or immersion heater is normally used to make up the difference.

Most solar hot water systems are just designed to provide the hot water you use for bathing, showering and hot taps.

Solar water heating systems include storage tanks and solar collectors. There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don't.

 Direct circulation systems

Pumps circulate household water through the collectors and into the home. They work well in climates where it rarely freezes.

Indirect circulation systems

Pumps circulate a non-freezing,heat transfer fluid through the collectors and a heat exchanger. This heats the water that then flows into the home. They are popular in climates prone to freezing temperatures.

Passive solar water heating systems are typically less expensive than active systems, but they're usually not as efficient. However, passive systems can be more reliable and may last longer. There are two basic types of passive systems:

· Integral collector-storage passive systems

These consist of a storage tank covered with a transparent material to allow the sun to heat the water. Water from the tank then flows into the plumbing system. These work best in areas where temperatures rarely fall below freezing. They also work well in households with significant daytime and evening hot-water needs.

· Thermosyphon systems

Water is heated in a collector on the roof and then flows through the plumbing system when a hot water faucet is opened. The majority of these systems have a 40 gallon capacity.

Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank.

Three types of solar collectors are used for residential applications:

· Flat-plate collector

Glazed flat-plate collectors are insulated, weatherproofed boxes that contain a dark absorber plate under one or more glass or plastic (polymer) covers. Unglazed flat-plate collectors -- typically used for solar pool heating -- have a dark absorber plate, made of metal or polymer, without a cover or enclosure.

· Integral collector-storage systems

Also known as ICS or batch systems, they feature one or more black tanks or tubes in an insulated, glazed box. Cold water first passes through the solar collector, which preheats the water. The water then continues on to the conventional backup water heater, providing a reliable source of hot water. They should be installed only in mild-freeze climates because the outdoor pipes could freeze in severe, cold weather.

· Evacuated-tube solar collectors

They feature parallel rows of transparent glass tubes. Each tube contains a glass outer tube and metal absorber tube attached to a fin. The fin's coating absorbs solar energy but inhibits radiative heat loss. These collectors are used more frequently for our commercial applications.

Solar panels, also known as photovoltaics (PV), capture the sun’s energy and convert it into electricity to use in your home.

Installing solar panels lets you use free, renewable, low carbon electricity. You can sell surplus electricity to the grid or store it for later use.

And, against the backdrop of unstable energy costs, it’s a good time to consider taking advantage of the free, renewable energy that solar panels provide.

When the sun shines on a solar panel, solar energy is absorbed by individual PV cells in the panel. These cells are made from layers of semi-conducting material, most commonly silicon.

The PV cells produce an electrical charge as they become energised by the sunlight.

This electrical charge creates a direct current (DC) of electricity.

The current passes through an inverter to turn it into alternating current (AC) electricity. This is the kind of current needed for household appliances.

The cells don’t need direct sunlight to work and can even work on cloudy days. However, the stronger the sunshine, the more electricity generated

Solar panel systems tend to be made up of between six and 12 panels, with each panel generating around 400 to 450W of energy in strong sunlight.