Solar heating is the more simple and cost-effective technology. A black surface in the solar panel warms by absorbing light and this heat is transferred to a heat store (hot water cylinder) for later use. Normally domestic hot water rather than space heating requirements are met by solar - this is because hot water is used throughout the year, while space heating demand peaks when solar energy is at its lowest. More on how solar heating works can be found here.
Solar water heating can provide 50-70% of the annual energy required to heat domestic hot water, reducing the overall energy consumption of a well insulated house by around 10-12%. (See Case Studies 001 and 002 here).
A PV solar panel converts light into electrical energy. A semi-conductor material in the panel produces a direct current when light lands on it. The direct current is converted to alternating current (AC) for use in the house or for export to the electricity grid.
PV requires more roof area, but unlike solar heating where the household demand places a limit on the energy saving, excess electrical energy can be exported, so the only technical limit on energy production is the area available for installation. |
Navigate 
