Rising electricity bills, expensive power sources and increasing demand for home equipment has made the traditional water heater an appliance viewed at with wariness. The cost of having water heated has become just too pricy and the common man can ill afford to use one his entire lifetime.

Solar water heaters are the latest rage, known for their energy-efficient functioning and great return on investment. They may cost more upfront but save money over time. Such an investment which promises savings, reliability and durability has been a hit with the masses and if you’re looking to cut utility bills, perhaps it’s time to consider making the switch.

Solar heaters are completely powered by the sun’s energy. This means power cuts and blackouts have no bearing on their function. They collect the most sunlight when the sun is at its brightest and store surplus hot water for use later. Australia, the land of sunny skies, presents the perfect environment for harnessing this energy. And even if you live in colder climes it’s still possible to enjoy what these heaters offer because contrary to popular belief, you don’t need hours of bright sun to get them working.

Active systems

Active solar heaters are primarily of three types, direct, indirect and drainback. In direct systems, water is directly heated in solar collectors and circulated into your house. They’re best suited for regions that don’t experience very cold or freezing conditions as the absence of heat exchangers means very cold/freezing water cannot be heated effectively.

Indirect systems, meanwhile, use fluid mixtures circulated through collectors. The heat collected is then transferred to the water to be heated which is stored in tanks. The systems are ideal for very cold and near-freezing climate conditions as the fluid mixture – typically antifreeze – prevents water from freezing. Of course, there’s a minimum freezing temperature below which the fluid may not work which is why it’s important that you choose a system which meets the expected minimum temperature of your region.

With drainback systems, water or glycol is circulated through the collector loop and is stored in a tank when the pump stops. A differential controller operates to start the pump to route water into the system. The entire operation functions only when the collector’s temperature is higher than the water stored in the tank so it’s ideal for cold climates as the stored water doesn’t influence the operation.

Passive systems

Passive solar heaters don’t use pumps but rely on gravity and the tendency of water to circulate when heated. They don’t have electrical components which makes them cheaper and at times, more reliable than active systems. Integral collector/storage and thermosyphon are the two types.

Integral systems are simple constructions that consist of a tank and all-round insulation except for one side facing the sun. Water is collected, heated and used in a single system i.e. the tank. Though basic, it serves its purpose in regions that see a lot of sunlight and for people who need hot water mainly during the day or in the evening. Once night falls, the collected hot water cools and can’t be heated till the next sunny day.

Thermosyphon systems depend on water’s tendency to become lightweight as it’s heated. The heated water flows to the storage tank and is piped through the plumbing system. Cool water flows down to pipes in the bottom of the collector which aids circulation.