The systems may be used to heat water for a wide variety of uses, including home, business and industrial uses. Heating swimming pools, underfloor heating or energy input for space heating are more specific examples.

Solar thermal panels provide an effective way of saving CO2 in the supply of domestic hot water. While they are unlikely to be justified purely as a financial investment, the environmental benefits make them an attractive option.

Solar panels do not need planning permission if they are not greater that 9 sq. metres, less than 4 metres in height, and not within 5 metres of a boundary. However planning permission is needed for all installations on listed buildings. Planning permission is also needed anywhere within a conservation area, unless the installation is not visible from a public road or footpath.
Advice should be sought from your local planning department for such installations.

Solar water heating systems almost always require a backup system for cloudy days and times of increased demand.
Conventional storage water heaters usually provide backup and may already be part of the solar hot water system package. A backup system may also be part of the solar collector, such as rooftop tanks with thermosyphon systems. Since an integral-collector storage system already stores hot water in addition to collecting solar heat, it may be packaged with a demand (tankless or instantaneous) water heater for backup.