For our personal hygiene and some housework, we require hot water. For this, we commonly use a heater, that we know as "boiler", and that it works with gas or electricity, it's quite expensive.
But if we install a solar water heater, it serves to heat practically all the water we need for bathing, to wash clothes, wash the dishes... Solar water heater heat water only with energy from the sun and without consuming gas or electricity. Even in cloudy days, the technology of solar water heater allows it to continue producing hot water, if the water is not hot enough, you can also use a accessory called electric heater as an assisted heater, and if you also have boiler and in combined installation with solar water heater, the boiler will then automatically enter as a backup to keep the water at the required temperature, solar water heater is autonomous and work automatically with the boiler, so you don't have to worry about running out of hot water in very bad weather conditions, as well as when for some reason the demand for hot water is higher.