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Solar hot water systems

Trust the Caboolture solar hot water specialists. We install, service and replace both roof-mounted and split solar hot water systems — quickly, compliant and designed for longevity.

Solar hot water systems are available in two main styles

Solar hot water systems come in two main configurations—roof-mounted and split—offering a range of tank capacities and designs to fit different homes, climates and sites. Aside from lowering your household’s environmental footprint, the primary benefit is the noticeable reduction in your electricity bills. Electric hot water units operate similarly to an electric kettle, using a heating element. In Queensland, common element ratings are 1.8kW, 2.4kW and 3.6kW (with 4.8kW elements seldom used because of their heavy power consumption). These sizes are standard across major manufacturers such as Rheem, Dux, Vulcan, AquaMAX and Rinnai. Bear in mind that element size does not affect the efficiency rating. A 1.8kW element consumes half the power of a 3.6kW element but will require roughly twice the time to bring the same volume of water to the same temperature. Contemporary electric hot water systems are constructed with either: Mild steel tanks coated in vitreous enamel and safeguarded by a sacrificial anode, or Stainless steel tanks for greater longevity. Copper-style water heaters are no longer manufactured.

Need solar hot water fitted quickly? We can sort it for you!

Roof-mounted thermosyphon solar hot water systems.

Roof-Mounted Solar Hot Water Systems

This is the conventional style of solar hot water arrangement, where both the storage tank and solar collectors are installed on the roof. These setups have been common in Australia for decades and remain a reliable method for heating household water.

How They Work

The system operates using simple thermosyphon principles:

Cooler water sinks to the lowest part of the tank and flows into the solar collectors.

As the water warms inside the collectors, it becomes buoyant and returns up into the storage tank.

This natural circulation repeats itself, keeping the tank replenished with hot water.

Modern Improvements

Older designs often discharged excess water through the pressure and temperature relief valve when the system overheated. Current thermosyphon models typically include a flow control valve that limits circulation once water reaches about 60°C.

This reduces unnecessary water loss, although it can also mean the system stores slightly less hot water than earlier versions.

On very hot days these systems can sometimes create a rumbling sound when taps are opened, caused by superheated water moving through the collectors as pressure drops.

Tank & Collector Options

Collectors are available in various sizes depending on the manufacturer, offering different levels of solar capture.

Evacuated tube collectors are generally not recommended in Queensland because they can generate excessive solar gain and risk boiling water away for much of the day; they’re better suited to cooler, less equatorial regions.

Storage tanks come in stainless steel or vitreous enamel-lined mild steel options.

Considerations

The primary disadvantages of roof-mounted systems are their weight and appearance:

A full storage tank can tip the scales at over 500 kg, imposing a substantial load on the roof structure.

Many homeowners also find the large, visible tank less attractive.

Call Caboolture Hot Water on 1300 218 122 for clear, local advice from a Caboolture plumber about which solar hot water system, installation or repairs will suit your home — gas and electric options available.

Ground-mounted split-system solar hot water heaters

A split solar hot water system places the storage tank at ground level while only the solar collectors sit on the roof. Collectors may be flat panels or evacuated tubes—but evac tubes are generally not advised for Queensland’s conditions because they can overheat, lose water to boiling and produce unnecessary rumbling sounds.

How they work

Storage tanks commonly come in 250L, 315L and 400L capacities.

A temperature sensor at the collectors and another at the tank tracks the difference in heat.

When the collectors are around 10°C warmer than the tank, a small circulation pump (typically 25W or less) switches on, pumping roughly 2–3 litres per minute through the panels.

This moves heat captured by the collectors back into the tank, where natural convection causes the hottest water to rise to the top.

The pumps are quiet and use very little electricity—in many cases they consume less power in a day than the display on your microwave.

Build & installation

Copper flow and return piping is recommended to withstand the high temperatures involved.

At Caboolture Hot Water, we run these copper pipes in one continuous length with no joints or fittings in the roof cavity, and wrap them in 25mm high-temperature, UV-rated insulation to reduce heat loss.

Performance

Panel surface temperatures can reach up to 120°C, and some systems can heat storage tanks to around 75°C.

Once the tank hits the set temperature, water stays in the collectors until usage lowers the tank temperature enough to restart circulation.

Why quality matters

Picking a reputable brand is essential. Many low-cost imports use inferior parts that lead to significant faults and extra costs for homeowners. The extra upfront cost for a dependable system is small compared with the long-term reliability and peace of mind.

Contact Caboolture Hot Water on 1300 728 122 for straightforward, impartial advice on the best solar hot water system for your home.

Flat panel solar collector

Flat plate collectors are the most widely used solar hot water panels in Australia and suit almost any climate or installation location. How they operate Each collector contains a copper manifold with flat, powder‑coated black plates designed to absorb maximum heat. As water moves through the copper tubing, heat is transferred by either: Thermosyphon circulation (for roof‑mounted systems, using the natural rise of hot water and fall of cold water), or A circulation pump (for split systems where the storage tank sits at ground level). The collectors are sealed beneath toughened glass and housed within a fully insulated frame to retain heat and deliver reliable long‑term performance. Efficiency These collectors can produce heat even without full sun. On cloudy days they can still raise water temperature to about twice the ambient air temperature — for instance, with a 26°C air temperature the panels can heat water to roughly 52°C. Installation The number of panels required is determined by your storage tank capacity. Typically, most systems need two to three panels to match the size of common hot water storage tanks.

Evacuated-tube solar collectors

Evacuated tube systems comprise multiple glass tubes, each housing a copper rod charged with a heat-transfer fluid. The tubes fit into a top-mounted manifold on the collector, where solar heat is captured and conveyed to the storage tank. System design These collectors come in sets of 12, 18, 24 or 32 tubes, selected according to tank capacity and installation needs. Extremely efficient — the glass surfaces can reach around 250°C in full sun. Suitability They were developed for European-style climates with weaker sunlight and lower sun angles. They perform well in cooler Australian regions such as southern NSW, Victoria, South Australia and southern WA. In Queensland, though, they are often overly effective, which can cause overheating, increased water loss and gurgling or rumbling as water boils inside the tubes. Considerations Only a small number of suppliers still carry evacuated tube systems in Australia. They generally cost about $1,000 more than flat plate collectors and do not provide meaningful advantages in Queensland’s climate. For most Caboolture homes, we do not advise evacuated tubes; flat plate hot water systems offer superior value and more reliable performance locally.

Call Caboolture Hot Water on 1300 728 122 for professional, impartial, evidence-based guidance from a local Caboolture plumber with over 20 years serving South East Queensland.

You can call our Caboolture team evenings and weekends on 0413 861 166

At Caboolture Hot Water, we keep a broad selection of solar hot water systems on hand for prompt installation. By carrying the key models we supply, you won’t be left waiting for parts — your new system can be fitted quickly without hold-ups. We also provide Easy Payment Plans to help spread the initial cost. With terms of 1 to 3 years and fortnightly repayments following a small deposit, repayments can be comparable to the savings you’re already making on your electricity bills.