Understanding Solar Hot Water Systems

Studies indicate that some 40% of our gas and electric energy consumption is traceable to our hot water usage, which is very much a cause for concern due to the observed high carbon emissions of this usage. Yet, we have in our midst the single unlimited energy source of all, the sun. With the invention of solar hot water systems and the support offered by the government towards shifting to this alternative, we can now have a clear and lasting solution to lessening our carbon footprint.

Solar hot water systems

As a solution, solar hot water systems seek to utilise solar energy to replace the use of gas and electric energy in producing our hot water requirements. The system uses two major component parts, the solar energy collector and the storage tank. The solar collectors capture the heat of the sun and transfer this heat to copper tubing where water passes to be heated. This hot water is then led to a storage tank where the hot water is accumulated and kept before it is distributed to certain areas of the house, usually the kitchen, laundry and bathrooms.

Types of solar hot water systems

We may classify solar hot water systems according to the way the sun’s energy is collected, as well as the manner that the heated water is accumulated and stored. In terms of energy collection, there are two types: the flat plate system and the evacuated tube system.

The flat plate

The flat plate system uses glass panels that sit directly above copper tubes which are mounted on the roof. These glass panels absorb the sun’s heat and transfer this heat directly to the copper tubing where water passes for heating. This hot water proceeds to the water tank where it is stored before it is distributed.

The water inside the tank sorts itself out by the principle of rising heat. Hot water rises and accumulates to the top of the tank where the exit leading to the distribution is located. The cold water which settles at the bottom of the tank is usually led to the entry port by a circulator or pump.

The evacuated tube

The evacuated tube system uses glass tubes arranged as panels which absorb the sun’s heat from the air and transfers this heat to the copper tubing underneath. Thus, as water passes through the copper tubing, the water is heated and led to the storage tank for accumulation and storage before it is distributed to the household users.

Storage installation

These two systems – flat plate and evacuated tube – can have their storage tanks installed in two ways. One by mounting on the roof side by side with the energy collector, and another by split-type, which is the storage tank is located on the ground close to where the hot water is needed most.


Ideally, the split-type should be the more appropriate installation for the tank. Indeed, the tank must be placed as near as possible to the utility areas. However, there are instances when the tank may not be suitably located and the only appropriate site would be near the collectors, hence, the roof mounting.

Roof mounted

If the storage tank and the solar energy collector are to be mounted on the roof, we must make sure that the bearing capacity of the site, where these two units are to be installed, has been checked and double checked. Of course, more than the bearing capacity, the main consideration in the selection of the roof site is the area with the greatest sun exposure.

Making your choice

Whether you choose the flat plate system or the evacuated tube system is immaterial, since both systems may be qualified for renewal energy certificates (REC) from government regulators. Your solar hot water system provider should be able to give you all the information you need to enable you to make a well-informed decision.

Solar Ark

We at Solar Ark would be delighted to help you in the best way we can to arrive at a well-informed decision.

When you go solar, go SolarArk; Australia’s Highest Performer (

It’s a company you can rely on for having one of the highest rebates, being of the highest quality and efficiency offering some of the greatest savings and longest warranty.

Please call us at 1300 670 966.

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