Feeling the pinch of soaring hot water bills? In Perth, heating water with grid electricity can cost you around $1,000 a year. But what if you could cut those bills by up to 90% using our city’s 3,000+ hours of sunshine?
That’s where solar hot water system comes in. It turns free, clean sunlight into endless hot water, cutting costs and carbon emissions in one go.
In this guide, you’ll discover how solar-powered hot water works, the top system types, installation steps, WA rebate opportunities, maintenance must-dos, and your potential ROI.
Let’s dig in.
What Is a Solar Hot Water System?
A solar hot water system uses sunlight to heat your home’s water.
It consists of roof-mounted solar thermal collectors and an insulated storage tank. The collectors absorb the sun’s heat and transfer it to water or a heat-transfer fluid in pipes. Solar heating then replaces much of the electricity or gas normally used for hot water, cutting your utility bills.
How Does Solar Hot Water Work?
Solar hot water involves capturing sunlight, transferring heat, storing it, and using it on demand. Here’s the simple magic:
When the sun’s out in full force, your rooftop solar collectors get to work soaking up those rays and converting them into heat. As the collectors warm the water or heat-transfer fluid inside them, that hot water naturally rises. A pump gently feeds cooler water into the bottom of your storage tank, pushing the warmed water to the top. When you turn on a hot tap, water from the top of the tank flows straight into your home. No waiting, no extra electricity.
Your Options: Solar Collectors & Heat Pumps
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Solar Collectors: Your Sunlight Harvesters
Solar collectors are the heart of any solar hot water system, built specifically to trap and hold solar energy. They look like panels but heat water, not electricity:
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Flat-Plate Solar Collectors
Think of a flat, dark panel under a protective glass cover. Inside, copper pipes snake through an absorber plate. Sunlight heats the absorber, and the fluid circulating through the pipes carries that warmth to your insulated storage tank.
Flat-plate collectors are affordable, reliable, and perfect for sunny Perth days.
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Evacuated-Tube Solar Collectors
Picture rows of glass tubes, each with a copper heat pipe running down the middle. Between the tubes is a vacuum. This stops heat from escaping.
Sunlight warms the copper pipe, which transfers its heat to a manifold and then into your water. Because of the vacuum seal, evacuated tube solar hot water collectors stay super-efficient even on cooler or cloudy days.
They’re versatile too. Ideal for homes, businesses, or larger commercial hot water systems. They typically run 20–40% more than flat plates, but they gain more heat per unit area.
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Heat Pump Water Heaters
Heat pump hot water systems aren’t solar collectors, but they’re another efficient hot-water option.
A heat pump uses electricity to extract heat from the air and transfer it to your water. They run day and night even without sun and perform well in Perth’s climate. They can cut water-heating energy by 60–70%. Like solar collectors, heat pumps qualify for rebates and reduce your utility bills.
Hot Water from Roof to Tap | 3 Simple Steps
- Capture & Circulate: A small circulator pump moves water through your chosen collector type, absorbing heat along the way.
- Store & Stratify: The heated water rises to the top of an insulated tank, ready for use, while cooler water settles at the bottom.
- Instant Hot Water: Open a hot-water tap, and water from the hottest part of the tank flows directly into your shower, sink, or dishwasher, bringing solar-powered hot water right where you need it.
Now that you know the basic roof-to-tap process, let’s explore how the water actually circulates through your system, passively or with a pump.
How Water Circulates: Thermosiphon (Passive) vs. Pumped (Active)
In thermosiphon circulation system, hot water rises into a roof-mounted tank above the panels by natural convection. It is simple and reliable, but requires the tank to be on the roof.
In pumped circulation system, a small electric pump circulates fluid:
- Direct systems pump household water through the panels
- Indirect systems pump a non-freezing heat-transfer fluid through the panels and a heat exchanger.
Pumped systems allow the tank to sit on the ground. It is useful if roof space or structure is limited and better protect against freezing.
Solar Water Heater Setup & Installation
Before any pipes or panels go up, we begin with a thorough site assessment to tailor your solar water heater setup perfectly to your home’s conditions.
Site Assessment & Design
A professional survey checks your site:
- Roof orientation & tilt – In Perth, a north-facing roof at 20–30° tilt captures the most sun.
- Shading – Avoid any shade on the panels during peak sun hours. Even a small shadow can cut output significantly.
- Tank location – Decide if the tank will sit on the roof (tank-on-roof design, enabling thermosiphon) or on the ground (split system with a pump). Roof tanks need solid roof support; ground tanks take more space at ground level.
- System components – A full solar hot water setup includes solar collectors, an insulated storage tank, a circulation pump (if active), a controller/thermostat, and a backup heater (electric or gas). Proper piping, valves and controls must be included for safe, efficient operation.
How to Install Solar Hot Water System | Step-by-Step Installation Process
After assessing the site, now, we move on to the step-by-step installation.
- Planning & permits: Determine system size based on household size and hot-water usage. Obtain any required building/plumbing permits.
- Mount collectors: Securely fix the solar collectors to the roof using rails and flashing. Ensure panels are angled and fastened to handle wind and weather.
- Plumbing: Connect the collectors to the storage tank. In a pumped system, install the circulation pump and route insulated pipes between the tank and house. Install safety valves (expansion relief, check valves) as needed.
- Electrical & backup: Wire the pump, controller and any sensors. Install and connect the backup electric element or gas heater to power or gas supply. All electrical work must meet code.
- Testing & commissioning: Fill and pressurise the system, bleeding out air. Check all connections for leaks. Run the system: on a sunny day, the pump should circulate hot fluid and the tank temperature should rise. Adjust the thermostat/controller and insulate any exposed piping. A final inspection ensures safe operation.
Looking to pair your solar water heater with battery storage? Check out our solar and battery systems.
Benefits of Going Solar for Hot Water
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Cost Savings:
Solar can eliminate 50–90% of hot water bills. In Perth’s sunbelt climate, that means about $1,000 saved each year. WA’s avg. bill is $1,184/year, with 18% for water heating, so solar cuts a big slice off your bill. Most systems pay for themselves in 5–10 years after rebates and incentives.
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Environmental Impact:
Water heating is a heavy energy user which is around 25% of home usage. An electric water heater can emit 3 tonnes of CO₂ per year (about as much as driving an average car). Solar hot water cuts nearly all of that, equivalent to ‘taking a small car off the road’ every year.
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Reliability & Longevity:
Solar hot water systems last a long time. Collectors are rated for 20–30 years, and tanks 15–20 years. There are no fuel costs, and minimal electricity is needed (just for the pump and occasional boost). With routine maintenance, you’ll enjoy decades of hot water from free sunlight.
Solar Hot Water Rebates: Want a Rebate & Save Money on Hot Water Heating?
Great incentives are available. The federal Small-scale Renewable Energy Scheme (STC) gives credits worth thousands off your cost.
On top of that, Western Australia offers its own rebates. For example, Perth homeowners installing a qualifying solar energy hot water system can receive up to $1,000 back. High-efficiency boost systems get smaller rebates ($300), and heat pump systems also qualify for up to $1,000.s
How to apply for WA rebates for solar hot water system?
- Check eligibility: You must own the home and be on an approved electricity plan.
- Hire an authorised installer: Only registered installers like Renostain can submit rebate claims.
- Gather documents: Keep your supplier invoices (GST-inclusive) and energy account details.
- Submit the claim: Your installer usually lodges the application with the WA government or your electricity retailer.
- Receive credit: Approved rebates typically appear as a credit on your electricity bill.
Ask your installer about current promotions and solar hot water specials as they often include help with rebates.
Tips for Solar Hot Water Maintenance & Troubleshooting
Keep your system performing well with routine checks:
- Flush & descale: Every 1–3 years, drain and flush the tank to remove mineral buildup. It improves efficiency.
- Inspect valves & pipes: Annually check the pressure-relief valve, check valves, and all fittings for leaks. Ensure insulation on hot-water pipes is intact.
- Clean collectors: Wash the panels or tubes with a gentle spray if dusty or dirty (frequency depends on local conditions).
- Test controls: Verify the pump, thermostat and controller are working. Test the backup heater. Replace the sacrificial anode in the tank if your model has one.
- Antifreeze refresh: For closed-loop (indirect) systems, replace the glycol solution every 3–5 years to maintain freeze protection.
Common issues & fixes:
Low output on cloudy days is normal; the backup heater tops up when solar gain is low. In rare freezes, ensure antifreeze or drains are working. If a pump fails, check its power and replace it if needed. Tighten any leaks promptly. Strange noises mean scale or air so try flushing the tank.
Professional service once a year is wise. A technician will check all components and ensure peak performance.
Ran out of hot water or notice persistent problems?
Call the Professionals – Renostain
If you see leaks, corrosion or loss of performance, Renostain’s expert team can help.
We offer comprehensive maintenance plans and 24/7 support for solar hot water systems.
Let our licensed technicians handle annual inspections and quick repairs, so you get reliable hot water without the hassle. Our team will keep your system running at its best year after year. Check out our Hot Water Audit page for a complete system check.
So, Is It Worth Getting Solar Hot Water?
For most Perth homes, absolutely.
The upfront cost is quickly offset by energy savings and rebates. You’ll enjoy decades of hot water from free sunlight and a much smaller carbon footprint. In short: with Perth’s abundant sun and high energy costs, a solar hot water system is usually a smart investment.
Tired of soaring hot water bills?
Switch to Solar Hot Water System Today | Save Up to 90% on Bills
Choose Renostain for custom solar hot water engineering and support.
We design systems around your needs, from grid-tied roof setups to containerised off-grid solutions.
Our packages bundle professional installation, annual servicing and 24/7 support, giving you a full turnkey solution. Start saving on energy bills and emissions right away.
Don’t wait!
Get Your Free Solar Hot Water Quote Now
FAQs
Q1: How much does a solar hot water system cost in Australia?
In Australia, a typical residential solar hot water costs about $4,000–$8,000 fully installed. The exact price depends on system size, roof vs. ground tank, pump vs. passive design, and whether the booster is electric or gas. Rebates (STCs, WA incentives) can greatly reduce your net cost.
Q2: What is the lifespan of solar hot water systems?
Solar collectors last roughly 20–30 years, and storage tanks about 15–20 years. With regular maintenance, most systems will serve you well for 15–25 years or more.
Q3: How long does a solar hot water take to heat up?
On a sunny day, expect a full tank to heat in 2–4 hours of peak sunlight. Cloudy or winter conditions slow heating, so the backup heater automatically kicks in to ensure you still have hot water.
Q4: How often does a solar water heater need maintenance?
Plan on annual maintenance. Each year flush the tank, check valves and controls, and clean the panels if needed. Keeping up with these simple tasks keeps the system efficient and reliable.
Q5: What is the best place to keep a solar water heater?
Install the collectors on a sunny, north-facing roof (for southern hemisphere) with minimal shade. The roof must be strong enough to support the panels and tank. Ground tanks should be placed on solid level ground. The goal is to maximise sun exposure on the panels all day.
Q6: Can a solar hot water system run on cloudy days?
Yes, but at reduced output. The collectors will still gather some heat on overcast days. But usually not enough for full demand. The backup heater will then top up the hot water as needed. Even on grey days, solar will preheat the water and reduce overall energy use.
Q7: Do I need a booster for my solar hot water system?
Almost certainly. A backup booster (electric or gas) is standard in solar hot water setups to ensure you always have enough hot water. In Perth, electric boosters are common and only run when solar heat alone isn’t enough.
