Solar Hot Water FAQ

A system comprises solar collectors, a storage tank, a gas or electric booster, and — for split systems — a controller and pump. There are two main types: Close Coupled (tank sits above the collectors on the roof, circulating by thermosyphon) and Split (tank on the ground, collectors on the roof, circulated by a pump).

It can cut your electricity consumption, costs and environmental impact by around two-thirds. Water heating accounts for roughly 40% of household electricity use, so a solar system can cut your overall usage by about 25% while also easing peak summer demand.

Yes — solar gain happens year-round during daylight hours. A clear winter day can actually yield more energy than an overcast summer one. Contribution varies: clear/sunny gives the highest gain, clear/cold is still reasonable, overcast/warm is reasonable, and overcast/cold gives the least.

The tank should hold one day's hot water supply plus some solar storage capacity. Tank size is matched to your household's consumption, and the number of collectors is matched to the tank size.

The component that absorbs solar energy — made up of a glass surface, fluid-filled tubes, heat-absorbing fins, a treated absorber surface, insulated casing or vacuum, and connecting pipework.

Flat Plate collectors (an insulated tray under glass, suited to areas without frost) and Evacuated Tubes (borosilicate glass tubes under vacuum, ideal for frost-prone areas — they can withstand temperatures down to -12°C).

Solar thermal systems convert solar radiation directly into hot water. Photovoltaic (PV) panels convert solar radiation into electricity instead.

A government-backed measure of the expected energy savings a system delivers over ten years — one STC equals one megawatt-hour saved, or roughly 100kWh a year. More STCs mean a larger upfront rebate.

A booster provides hot water during low-sun periods or times of high demand. Two options are available: gas or electric.