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Solar Hot Water Systems

Rooftop collectors heat your water straight from the sun, with a gas or electric booster for cloudy days. A 300 litre system costs $3,500 to $5,500 installed before the federal STC discount, which Solahart puts at $532 for its 302 litre system in Zone 3 (as at October 2026).

300L installed
$3,500 to $5,500
STC example, 302L, Zone 3
$532
Years of service
15 to 20
Most popular size
300L
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Solar hot water system on a terracotta tile roof: a stainless steel tank mounted above two flat plate collectors
A close-coupled system: the tank sits on the roof above two flat plate collectors.

How solar hot water works

Collectors on the roof capture sunlight and pass the heat to water stored in an insulated tank.

  1. Collect

    Rooftop collectors absorb sunlight and turn it into heat.

  2. Transfer

    The heat moves into the water by direct flow or through a heat exchanger.

  3. Store

    Hot water is stored in an insulated tank, on the roof or at ground level.

  4. Boost

    A gas or electric booster switches on when the sun is not enough.

Solar hot water system types

Choose between flat plate collectors (better value, warm climates) and evacuated tubes (higher efficiency, cooler climates).

Flat plate collector

The traditional design: a dark absorber plate under glass. Simple, durable and cost-effective.

Advantages

  • Lower upfront cost
  • Very durable
  • Easy maintenance
  • Good in warm climates

Watch for

  • Less efficient in cold or cloudy weather
  • Needs more roof area
  • Can overheat in summer
Best for
Warm climates (QLD, NT, northern WA)
Price
$3,000 to $5,000

Evacuated tube collector

Glass tubes with vacuum insulation around the absorber. Holds heat better and performs better in the cold.

Advantages

  • Higher efficiency
  • Works well in cold or cloudy conditions
  • Individual tubes replaceable
  • Needs less roof space

Watch for

  • Higher upfront cost
  • Tubes can break
  • More complex installation
Best for
Cooler climates (VIC, TAS, SA, highlands)
Price
$4,000 to $7,000

Solar hot water vs heat pump

Both are efficient ways to heat water. The better choice depends on your climate, your roof and what you value.
FactorSolar hot waterHeat pump
Upfront cost$3,000 to $7,000$3,500 to $5,500
Running cost$50 to $150 a year$150 to $250 a year
Cloudy daysNeeds boosterFull performance
Roof spaceRequired (north-facing)Not required
MaintenancePeriodic cleaningMinimal
Lifespan15 to 20 years10 to 15 years
Best climateSunny (QLD, WA, NT)All climates

Choose solar hot water if

  • You live in a sunny climate (QLD, NT, WA)
  • You have good north-facing roof space
  • You want the lowest possible running costs
  • You prefer simple, proven technology

Choose a heat pump if

  • You live in a cooler or cloudier climate (VIC, TAS)
  • You have limited or shaded roof space
  • You want steady performance all year
  • You already have solar PV panels
Learn more about heat pumps

Solar hot water brands

Established Australian and international manufacturers of solar hot water systems.

  • Rheem

    Warranty 5 to 10 years

    Flat plate & evacuated tube

  • Solahart

    Warranty 5 to 10 years

    Flat plate & thermosiphon

  • Apricus

    Warranty 10 years

    Evacuated tube specialist

  • Chromagen

    Warranty 5 to 7 years

    Flat plate systems

  • Hills

    Warranty 5 years

    Flat plate & evacuated tube

Solar hot water rebates

Federal STCs apply everywhere. Victoria adds a cash rebate, South Australia a retailer discount, and the ACT a loan.
  • FederalSTCs on every eligible system until 31 December 2030. Example: 14 certificates, about $532, on a 302 litre Solahart solar hot water system in Zone 3 installed in 2026.
  • New South WalesFederal STCs. The ESS page lists no amount for solar
  • VictoriaHalf the cost up to $1,000, or up to $1,400 for an Australian-made product, households with income under $150,000
  • South AustraliaRetailer discount under REPS WH1 (solar electric or solar gas), no set amount
  • ACTCheck with the scheme whether solar hot water qualifies for the loan
  • QueenslandFederal STCs. No state hot water scheme on our records
  • Western AustraliaFederal STCs. No state hot water scheme on our records
  • TasmaniaFederal STCs. No state hot water scheme on our records
  • Northern TerritoryFederal STCs. No state hot water scheme on our records

Rebate figures as at October 2026, at $38 a certificate. Sources checked October 2026. Sources: Clean Energy Regulator, solar water heaters and air source heat pumps; Clean Energy Regulator, register of air source heat pump models (updated 10 August 2026); Solahart, STC incentives (published 7 May 2025); NSW Government, Hot water upgrade incentive (updated 6 February 2026); Solar Victoria, Solar Homes hot water rebate (open as at 12 October 2026); SA Department for Energy and Mining, REPS activity WH1 specification 2026.1; ACT Government, Sustainable Household Scheme.

View all rebates by state

Solar hot water system prices by size

Prices depend on tank size, collector type and how complex the installation is. Here is a guide to typical installed costs before the STC discount.

For a breakdown by collector type, brand and tank size, see the solar hot water system price guide.

  • 180 to 250L

    Best for
    1 to 2 people
    Price installed
    $3,000 to $4,500

  • 300LMost popular

    Best for
    3 to 4 people
    Price installed
    $3,500 to $5,500

  • 325 to 400L

    Best for
    5+ people
    Price installed
    $4,500 to $7,000

Prices are indicative and vary by collector type, brand and installation requirements. The STC discount depends on the model and your STC zone; the installer shows the certificate count on the quote.

300 litre solar hot water system

The 300L system is the most popular size for Australian families (3 to 4 people). It gives enough hot water for daily showers, laundry and the kitchen while staying cost-effective to install and run.

Installed price
$3,500 to $5,500
STC example (Solahart 302L, Zone 3)
$532
Ideal household
3 to 4 people

Solar hot water in South Australia

South Australia's sunny climate suits solar hot water. Adelaide averages 4.7 peak sun hours a day, which keeps the collectors working.

SA solar hot water benefits

  • High sunshine hours, so the collectors perform well
  • Federal STCs, with the number set by the model and zone
  • Retailer discount under REPS activity WH1: heat pump, solar electric, solar gas or gas water heaters only. No set amount
  • SA’s high electricity prices mean faster payback
  • Flat plate collectors work very well in the SA climate

Recommended for SA

Adelaide's warm climate means flat plate collectors are usually the best choice: simpler, more durable and cheaper than evacuated tubes. A 300L system typically costs $3,500 to $5,500 installed before the STC discount.

View SA rebates

Frequently asked questions

How does solar hot water work?
Solar hot water systems use rooftop collectors to absorb sunlight and transfer the heat to water. The heated water is stored in an insulated tank for use through the day. Most systems include a booster (gas or electric) for cloudy days.
What is the difference between flat plate and evacuated tube solar?
Flat plate collectors are simpler, more durable and work well in warm climates. Evacuated tube collectors are more efficient in cooler climates and cloudy conditions because the vacuum insulation reduces heat loss. Tubes are more fragile, but individual tubes can be replaced.
How much does a solar hot water system cost?
Solar hot water systems typically cost $3,000 to $7,000 installed, depending on the system type, tank size and how complex the installation is. Federal STCs come off the price: Solahart lists 14 certificates, about $532, on a 302 litre Solahart solar hot water system in Zone 3 installed in 2026 (as at October 2026). The certificate count depends on the model and your zone, so check it on the quote.
Do solar hot water systems work on cloudy days?
Solar thermal collectors still absorb some heat on cloudy days, but output drops a lot. Most systems include a gas or electric booster that switches on when solar heating is not enough.
What size solar hot water system do I need?
System size depends on household size and hot water use. Typically, 1 to 2 people need 180 to 250L, 3 to 4 people need 250 to 325L, and 5 or more need 325 to 400L. Cooler climates need a larger collector area.
How long do solar hot water systems last?
Quality solar hot water systems last 15 to 20 years. Tanks typically carry 10-year warranties, while collectors can last 20 years or more. Evacuated tubes may need the occasional replacement.

Get a solar hot water quote

Find out if solar hot water suits your home. A licensed local installer looks at your roof, climate and usage, and recommends the system that fits.

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