Solar power can be added to an existing house, which may involve retrofitting, or built into its design. Some solar power is acquired by directly heating water through tubes on the roof, and other ways of passively collecting heat. However solar energy is captured by solar panels, which produce electricity.
Houses can have solar heating added, sometimes by altering their design [retrofitting] and at other times, they can be designed with it in mind. Solar heating for your home may be active or passive.
Active heating involves machinery with working parts, but passive is cheaper and involves designing the house to collect heat. Both active and passive involve electricity saving.
This can mean having tubes containing water running across the south-facing side of your roof to collect the heat of the sun and transfer it to your hot water system. These roof panels will consist of tubes, lying above a black panel and covered with glass to trap heat. The water flows to the hot water system. Convection keeps the water moving.
In northern climates, an auxiliary heater might be used to bring the water to the right temperature. If a pump is used, the system is classed as active solar heating.
A Trombe wall might be built into your design. This is a south-facing wall consisting of a layer of black material covered by glazing material which traps heat behind it. The heat trapped behind the wall can be released into the house by opening ventilators.
Solar heating can be as simple as a conservatory, which, if south facing, should be like a greenhouse and trap heat. This can then be passed into the house by opening its doors.
Sun tubes (see the picture below) are an ingenious way of saving electricity by transferring sunlight from lighter to darker parts of houses, such as cellars.
Solar panels can be used to generate electricity. They are often sited on the roof, but this need not be the case, as they can be connected to the metre by cables. They must be south facing to catch the sun, if you are in the northern hemisphere.
Connecting them up requires electrical skills. While passive heating can be made with D.i.Y skills, solar panels require a kit, which must be purchased.
However, there are some schemes that allow householders to not only generate their own solar electricity, but also to sell surplus power back to the grid through the electric metre.
A final word
In general, though, in the United Kingdom, houses cannot be powered on solar energy alone and need a supplementary supply.