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Solar hot water systems

Trust the Gympie solar hot water specialists. We fit, service, and replace both roof-mounted and split solar hot water systems—quickly, to code, and designed for longevity.

Solar hot water systems are available in two distinct designs

Solar hot water systems come in two primary configurations—roof-mounted and split—with a range of tank capacities and layouts to match different properties, climates and siting requirements. Aside from cutting your environmental footprint, the main benefit is the notable reduction in your energy bills. Electric hot water units operate much like a kettles’ heating element and, in Queensland, are commonly offered in 1.8kW, 2.4kW and 3.6kW ratings (the rarer 4.8kW elements are seldom used because of their heavy power demand). These element sizes are consistent across leading manufacturers such as Rheem, Dux, Vulcan, AquaMAX and Rinnai. Bear in mind that element size does not alter the system’s efficiency rating. For instance, a 1.8kW element consumes half the power of a 3.6kW element, but will require roughly double the time to raise the same volume of water to the same temperature. Contemporary electric hot water systems are constructed with either: Mild steel tanks coated with vitreous enamel and safeguarded by a sacrificial anode, or Stainless steel tanks for greater longevity. Traditional copper-style water heaters are no longer manufactured.

Need solar hot water installed quickly? Gympie Hot Water can help!

Roof-mounted thermosyphon solar hot water systems.

Roof-mounted solar hot water systems

This is the classic solar hot water arrangement where the storage tank and the solar collectors are installed together on the roof. These setups have been common across Australia for decades and still provide an efficient method of heating household water.

How they work

They operate using basic thermosyphon principles:

Cooler water drops to the lowest point in the tank and flows down into the solar collectors.

As the water warms in the collectors it becomes buoyant and rises back into the storage tank.

This continual natural circulation maintains a supply of hot water in the tank.

Modern improvements

Older thermosyphon units often vented excess water through the pressure-temperature relief valve during overheating. Current models commonly include a flow-control valve that limits circulation once water reaches around 60°C.

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

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

Tank and collector options

Collector sizes vary by manufacturer, offering different levels of solar heat capture.

Evacuated tube collectors are generally not advised in Queensland because they can generate excessive solar gain and risk boiling off water through much of the day; they’re better suited to cooler, less sun-intense regions.

Storage tanks are typically available in stainless steel or vitreous enamel lined mild steel.

Considerations

The primary downsides of roof-mounted systems are their visual impact and weight:

A filled storage tank can exceed 500 kg, imposing a substantial load on the roof structure.

Many homeowners also prefer not to have a large tank visible on the roof for aesthetic reasons.

Call Gympie Hot Water on 1300 218 122 for clear, experienced advice on which solar hot water system, installation or repair will suit your home. We’re a local Gympie plumber specialising in hot water systems, gas and electric options.

Split-system, ground-mounted solar hot water units — ideal for Gympie hot water needs, installation and service by a trusted Gympie plumber skilled in solar hot water systems.

A split solar hot water setup places the storage tank at ground level while only the solar collectors sit on the roof. Collectors may be flat panels or evacuated tubes — however evacuated tubes are generally not suitable for Queensland’s conditions because they can overheat, lose water to boiling, and produce avoidable rumbling sounds. How they work Storage tanks are commonly available in 250L, 315L and 400L capacities. A temperature sensor on the panels and another on the tank compares heat levels. When the panels are around 10°C warmer than the tank, a small circulation pump (typically 25W or less) kicks in, circulating roughly 2–3 litres per minute through the collectors. This moves heat from the roof-mounted collectors into the tank, and natural convection causes the hottest water to rise to the top. The pumps run quietly and use minimal electricity — often consuming less power each day than a microwave clock. Build & installation Copper flow and return pipes are recommended to withstand high temperatures. At Gympie Hot Water, we install these pipes as a single continuous run with no joints or fittings in the roof cavity, and insulate them with 25mm high-temperature, UV-rated insulation to reduce heat loss. Performance Panel temperatures can reach up to about 120°C, and some systems let storage tanks heat as high as 75°C. Once the tank hits its set temperature, water stays in the collectors until use lowers the tank temperature enough to restart circulation. Why quality matters Picking a trusted brand is essential. Low-cost imports with inferior components have caused significant problems and extra expense for many homeowners. The additional cost for a dependable system is small compared with long-term reliability and peace of mind. Contact Gympie Hot Water on 1300 728 122 for straightforward, impartial advice about selecting the right solar hot water system and installation for your home.

Flat-panel solar collector

Flat plate collectors are the most widely used solar hot water panels across Australia and are well suited to nearly any climate or site. How they work Each panel contains a copper manifold with flat plates finished in black powder-coat to absorb maximum heat. As water moves through the copper tubing, heat is transferred either by: Thermosyphon circulation (for roof-mounted setups that rely on natural convection of hot and cold water), or A circulation pump (for split systems where the storage tank sits at ground level). The collectors are sealed with toughened glass and housed in a fully insulated frame to trap heat and provide durable performance. Efficiency These panels can produce heat even without direct sun. On cloudy days they’re still capable of raising water temperature to around twice the ambient air — for example, if the air is 26°C the panels can heat water to roughly 52°C. Installation Panel quantity is determined by the size of your storage tank. Typically two to three panels are needed to match the capacity of most common tanks. Gympie Hot Water provides local advice and installation from experienced Gympie plumbers for solar hot water systems, including gas and electric integration, repairs and full system installation.

Evacuated-tube solar collectors

Evacuated tube hot water systems consist of multiple glass tubes, each housing a copper heat pipe charged with a thermal transfer fluid. The tubes connect into a top-mounted manifold on the collector, where the captured heat is passed through to the storage tank. System design These collectors come in sets of 12, 18, 24 or 32 tubes, chosen to match tank capacity and site-specific installation needs. Extremely efficient—under strong sun the tube surfaces can reach temperatures approaching 250°C. Suitability They were developed for cooler European-style climates with lower sun angles and reduced sunlight intensity. They perform well in cooler Australian areas such as southern NSW, Victoria, South Australia and southern WA. In Queensland, however, evacuated tubes are frequently over-capable, which can cause overheating, excess water loss and boiling noises in the tubes. Considerations Only a small number of suppliers still stock evacuated tube systems in Australia. They generally cost about $1,000 more than flat plate collectors and rarely offer meaningful advantages in Queensland’s climate. For most Gympie homes, Gympie Hot Water recommends flat plate systems as they typically provide better value and more reliable performance in local conditions.

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

You can call our Gympie Hot Water team on 0413 861 166 — we're available on weekends and after-hours.

At Gympie Hot Water, we hold a broad selection of solar hot water systems on hand for prompt installation. Because we keep the key models we supply in stock, you won’t be left waiting for deliveries—your new hot water system can be fitted without unnecessary delays. We also provide Easy Payment Plans to help spread the initial cost. With terms from 1 to 3 years and fortnightly repayments following a small deposit, your payments can align closely with the savings you’ll see on your electricity bills.