Solar based

Water flows through roof panels, where it is heated by sunshine and then is introduced into the hot water system.

What is solar boosted hot water?

These systems heat water using a combination of solar panels and conventional heating elements, to top up the heat when it's not sunny. Solar boosted systems using continuous flow condensing water heaters offer an ultra high efficiency solution as the secondary heat source will only fire up then the water temperature needs to be boosted.

How do solar boosted hot water heaters work?

These types of water heater rely mainly on solar collector panels (not to be confused with electricity producing photovoltaic cells), or an evacuated tube array to heat water under. The water is then either collected in a tank above the panels (using a thermosiphon system) or one on ground level (using a split system). In low temperature conditions and colder climates, the sun may not be strong enough to maintain a consistently high water temperature on its own. In these situations the gas or electric booster will provide additional heat to the water.

Does there have to be an alternative heat source?

Yes. Current legislation demands it - this is to ensure that the temperature of the water regularly exceeds 60°C (in order to kill bacteria). The booster in such systems is a small burner or heating element that only kicks in when the water reaches a sufficiently low temperature. Continuous flow water gas water heaters can also be utilised in this arrangement, creating an ultra high efficiency solution.