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Solar hot water systems

Trust the Caloundra solar hot water specialists. We install, service and replace both roof-mounted and split solar hot water systems — quickly, compliant with regulations, and designed for long-lasting performance.

Solar hot water systems are available in two distinct styles

Solar hot water systems come in two primary configurations—roof-mounted and split—offering a range of tank capacities and layouts to match different homes, climates and sites. Aside from the environmental benefit of cutting energy consumption, the main upside is the noticeable reduction in your electricity bills. Electric hot water units operate similarly to a kettle, using a heating element, and in Queensland common element ratings are 1.8kW, 2.4kW and 3.6kW (with 4.8kW elements seldom used because of their heavy power draw). These element sizes are standard across leading brands such as Rheem, Dux, Vulcan, AquaMAX and Rinnai. Bear in mind that element size does not alter the system’s energy efficiency. For instance, a 1.8kW element consumes half the power of a 3.6kW element but will require roughly twice the time to heat the same volume of water to the same temperature. Contemporary electric hot water systems are constructed with either: Mild steel tanks finished with 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’re here to help!

Roof-mounted thermosyphon solar hot water systems.

Roof-Mounted Solar Hot Water Systems This classic solar hot water arrangement positions both the storage tank and solar collectors up on the roof. It’s a long-established method used across Australia and continues to be a reliable option for heating household water. How They Work These systems rely on simple thermosyphon principles: Cooler water settles at the lowest point in the tank and flows down into the solar collectors. As the water in the collectors heats, it becomes buoyant and rises back into the storage tank. This ongoing natural circulation keeps the tank replenished with hot water. Modern Improvements Older designs sometimes discharged excess water through the pressure and temperature relief valve during overheating. Contemporary thermosyphon models typically include a flow control valve that limits circulation once water reaches around 60°C. This reduces wasted water but can also mean less total stored hot water compared with older systems. On very hot days you may occasionally hear a rumbling noise when taps are opened — caused by superheated water moving through the collectors as pressure drops. Tank & Collector Options Collector sizes vary by manufacturer, delivering different amounts of solar gain. Evacuated tube collectors are generally not recommended for Queensland conditions because they can produce excessive solar gain and risk boiling off water for much of the day; they suit cooler, more southerly climates better. Storage tanks are offered in stainless steel or vitreous enamel–lined mild steel. Considerations The primary downsides of roof-mounted systems are their weight and appearance: A fully loaded storage tank can exceed 500 kg, which imposes a substantial load on the roof structure. Many homeowners also prefer to avoid the look of a large visible tank on the roof. Call Caloundra Hot Water on 1300 218 122 for clear, local advice on which solar hot water system — including installation, repairs and gas and electric options — is right for your home, or to speak with a Caloundra plumber.

Split-system, ground-mounted solar hot water units

A split solar hot water setup locates the storage tank at ground level while only the solar collectors sit on the roof. Collectors may be flat panels or evacuated tubes—but evacuated tube styles are generally unsuitable for Queensland’s climate because they can overheat, lose water through boiling and produce unnecessary rumbling sounds.

How They Work

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

A temperature sensor on the collectors and another on the tank track the differential.

When the collectors are about 10°C warmer than the tank water, 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 collectors into the tank, where natural convection causes the hottest water to rise to the top.

The pumps run quietly and use very little electricity—often consuming less energy each day than the clock on your microwave.

Build & Installation

Copper flow and return lines should always be specified to cope with high temperatures.

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

Performance

Collector surface temperatures can reach up to around 120°C, and some systems permit storage tanks to get as hot as 75°C.

After the tank hits its set temperature, water stays in the collectors until demand lowers the tank level enough to trigger the circulation again.

Why Quality Matters

Picking a trusted brand is essential. Many low-cost imports with inferior components have produced significant problems and hidden expenses for homeowners. The extra cost for a quality system is small compared with the long-term reliability and peace of mind.

Call Caloundra Hot Water on 1300 728 122 for honest, expert advice on the right solar hot water system for your home, including installation and repairs for gas and electric options.

Flat-panel solar collector

Flat plate collectors are the most widely used solar hot water panels across Australia and perform well in nearly any climate or roof location. How they operate Each collector contains a copper manifold with flat plates finished in black powder coat to maximise heat absorption. As water moves through the copper tubing, heat is transferred by either: Thermosyphon circulation (in roof-mounted arrangements, which use the natural rise of hot water and fall of cold), or A circulation pump (in split systems where the storage tank sits at ground level). The collectors are sealed beneath toughened glass within a fully insulated frame to trap heat and provide durable performance. Efficiency These panels can produce heat even without direct sunlight. On cloudy days they can still achieve temperatures up to about twice the surrounding air temperature—for example, with an ambient 26°C, water can be heated to roughly 52°C. Installation How many panels you need depends on your storage tank size. Most domestic systems use two to three panels to suit common hot water storage capacities.

Evacuated tube solar collectors

Evacuated tube hot water systems consist of multiple glass tubes, each housing a copper heat pipe filled with a thermal transfer fluid. The tubes slot into a top manifold on the collector, where solar energy is absorbed and conveyed to the storage cylinder.

System design

They come in sets of 12, 18, 24 or 32 tubes, selected according to tank capacity and installation needs.

Highly efficient—tube surfaces can reach temperatures up to about 250°C in strong sunlight.

Suitability

These systems are primarily engineered for cooler, European-style climates with lower sun angles and weaker sunlight.

They perform well in southern Australian regions such as southern NSW, Victoria, South Australia and southern WA.

In Queensland, however, their high efficiency can be problematic, causing overheating, excessive water loss and gurgling or rumbling as water boils in the tubes.

Considerations

Only a small number of suppliers still carry evacuated tube systems in Australia.

They usually cost about $1,000 more than flat plate collectors and generally don’t provide meaningful advantages in Queensland’s climate.

For most Caloundra homes, we don’t recommend evacuated tubes; flat plate systems typically offer superior value and more reliable performance in local conditions.

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

You can ring Caloundra Hot Water outside business hours and on weekends on 0413 861 166

At Caloundra Hot Water, we carry a comprehensive selection of solar hot water systems on-site for prompt installation. By keeping the primary models we supply in stock, you won’t have to wait for deliveries—your new hot water system can be fitted quickly and without hold-ups.

We also provide Easy Payment Plans to help spread the initial cost. With terms ranging from 1 to 3 years and fortnightly repayments following a small deposit, your repayments can be similar to the savings you’ll see on your electricity bills.

Caloundra Hot Water provides and fits solar hot water systems throughout Caloundra—quick, compliant and designed for longevity.

Let us guide you to the best choice for replacing or repairing your solar hot water system Caloundra Hot Water’s technicians are fully qualified to service and repair all types of hot water systems Call us NOW on 1300 728 122 or 0413 861 166 — available after hours and on weekends

The reviews shown below are genuine feedback collected from Google, Facebook and other review platforms — not fabricated testimonials written by the company.

Thank you for your honesty. Fantastic experience with your guys. Tradie left my yard in a clean state and well mannered with a new boiler installed and no problems. Definitely worth the phone call.

I had them out to my home yesterday after Jets plumbing came out and told me I needed a new water heater for $2270 when my old water heater was only 6 years old which seamed ridiculous and I do not have that sort of money floating around Turns out it only needed a new element and I saved myself over $2000 They came out within 3 hours of calling them and I had hot water again this morning, love hot showers in the morning, especially after 4 days of cold ones Honest, polite, knowledgeable and professional service provided

Needed repair on an evacuated tube HWS on my rental property. Great work and many thanks to Scott & Sarah for excellent prompt service that had it fixed quickly & without any fuss. Definitely recommended.

Saw an advert on a community page on Facebook. Sent the business a message and within 6 hours I had a technician onsite and had the computer board replaced. Great Service, Great Communication. Thank you

Great knowledge base and very helpful, even though we were not going to be customers (we are in NSW) these guys gave us the information we needed to fix our solar hot water system. If you have any doubt, check out the blog - these guys know theirstuff!

Excellent service and good sound professional advice, had a Dux heat exchanger hot water system fail. Called Dux who did not want to discuss as it is out of warranty, they arranged for their local guy to call me, spoke to a helpful lady who was going to ask the technical guy to call me, as they wanted to come out and charge me for telling me what I had already told them, this was 10.00am 14th December. In the meantime called Sun City as they originally installed this when I built the house 8 years ago, they were like a breath of fresh air, gave sound advice and installed a Bosch system the next day, with a better warranty, technical spec, and cheaper than the DUX. Still waiting the call from the DUX installer.........

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