Replacing your hot water system in 2026? Costs range from $1,200 for a basic gas storage tank to $8,000+ for a premium solar system – but the real question is 10-year total cost of ownership. This page has an instant estimator covering all seven common system types, state rebates, and the changeover complexity from your existing system.
Hot water system cost estimator
Indicative 2026 figures. State rebate schemes change often – check energy.gov.au and your state energy authority before signing.
Which system is right for you? Quick decision matrix
| Situation | Best-value pick | Why |
|---|---|---|
| Existing gas connection, low upfront budget | Gas storage or continuous | Cheapest install; running cost is reasonable if you use gas already |
| No gas, need cheap install | Electric storage (off-peak) | Lowest install; off-peak tariff keeps running cost manageable |
| You have solar PV (or plan to) | Heat pump | Runs on YOUR solar during the day; 3-4x more efficient than resistive electric |
| You want the lowest running cost long-term | Heat pump or solar HWS | Rebates knock $1,000-$3,000 off; running cost 50-75% lower than electric storage |
| North-facing roof, big household | Solar HWS (electric-boosted) | Direct solar heat plus boost; huge running cost savings |
| South-facing roof or heavy shade | Heat pump (not solar HWS) | Solar HWS needs decent roof aspect; heat pump works anywhere |
State-by-state 2026 rebates for hot water systems
NSW – Peak Demand Reduction Scheme (PDRS) + Empowering Homes
Up to $1,600 for eligible heat pumps under PDRS (means-tested). Solar HWS gets smaller amounts. Both require certified installers. Full details at energy.nsw.gov.au.
VIC – Solar Homes Hot Water Rebate
Up to $1,000 for eligible heat pumps and solar HWS. Waiting lists common – check current availability at solar.vic.gov.au before signing. VIC also offers 4-year interest-free loans on top.
QLD – Household Energy Savings program
Up to $1,000 for approved heat pumps and solar HWS. Program terms change – verify at qld.gov.au “hot water rebate”.
ACT – Sustainable Household Scheme
Interest-free loans up to $15,000 (covers HWS, solar, batteries). Practical value depends on how you’d otherwise finance the purchase; the $2,500 figure in the estimator is an indicative equivalent. Details at climatechoices.act.gov.au.
SA – Retailer Energy Productivity Scheme (REPS)
Around $500-800 for approved heat pumps, smaller for solar HWS. Delivered via participating retailers, not direct government. Check with your energy retailer.
TAS – Energy Saver Loan Scheme
Interest-free loans available; no direct rebate. Reasonable for households happy to finance the upgrade.
WA and NT – No dedicated hot water rebate
Federal STC rebate for heat pump and solar HWS still applies in both states (~$400-$1,400 depending on system).
Running cost reality: 2026 rates
Annual running cost per system type (typical 3-4 person household, 40L hot water per person per day):
| System | Annual running cost | 10-year running cost |
|---|---|---|
| Electric continuous | $700-1,300 | ~$10,000 |
| Electric storage (off-peak) | $450-800 | ~$6,250 |
| Gas storage tank | $400-700 | ~$5,500 |
| Gas continuous | $350-600 | ~$4,750 |
| Heat pump | $150-350 | ~$2,500 |
| Solar (gas-boosted) | $150-300 | ~$2,250 |
| Solar (electric-boosted) | $100-250 | ~$1,750 |
Assumes 2026 rates: gas 2.8c/MJ, electricity peak 32c/kWh (off-peak 20c/kWh). Rates vary by state and retailer. Running cost scales with household size – 5-6 person household adds ~30%; 7+ adds ~55%.
The seven system types explained
1. Gas storage tank
The traditional workhorse: a big insulated tank sitting outside, heated by a gas burner. Cheapest install ($1,200-2,400 for typical 3-4 person size), reasonable running cost. Downsides: gas prices rising 5-10%/yr in AU; some households can’t easily add a gas connection. Life: 8-12 years. Rheem and Rinnai dominate this segment.
2. Gas continuous (instantaneous)
Wall-mounted unit that heats water only when you turn on the tap. No standing losses so slightly cheaper to run. Handles unlimited hot water. Install cost $1,800-2,800. Best for larger households or if you dislike tank aesthetics. Rinnai Infinity and Rheem Metro are the most-searched models.
3. Electric storage (off-peak tariff)
Big insulated tank heated overnight on off-peak electricity. Cheap install ($1,400-2,200) but running cost is middle-of-pack. Off-peak tariff (~20c/kWh) makes it competitive with gas. Life: 8-12 years. Vulcan and Rheem entry-level dominate.
4. Electric continuous
Instant electric heating – no tank. Cheapest install but MOST expensive to run because it uses peak-rate electricity. Only makes sense for occasional-use scenarios (holiday houses, granny flats). Life: 10-15 years.
5. Heat pump
The current best-value pick for most households. Uses a refrigerant cycle (like a fridge in reverse) to extract heat from air and pump it into water. 3-4x more efficient than resistive electric. Install cost $4,000-5,500 mid-range; premium units (Sanden, Reclaim, iStore) run $5,500-8,000. Federal STC rebate typically covers $800-1,400. Runs happily on solar during daytime. Life: 12-15 years.
6. Solar HWS (electric-boosted)
Roof-mounted collector plus a storage tank plus an electric booster for cloudy days. Highest install cost ($4,500-6,500 mid-range) but lowest running cost of any system. Requires decent north-facing roof aspect. Life: 15-20 years for tank, 25+ for collectors. Solahart is the incumbent AU brand; Chromagen and Rheem also major players.
7. Solar HWS (gas-boosted)
Same as above but with a gas booster instead of electric. Marginally lower running cost if you already have gas; slightly higher install ($5,000-7,500). Less popular now as gas prices climb.
Replacing your old hot water system
If your existing system dies, you have two decisions to make: same-type replacement (fast, cheap) or upgrade to a more efficient type (higher upfront, faster payback).
Same-type replacement (quickest, cheapest)
Plumber removes old, installs new of the same fuel + tank type. Cost: base price above with no changeover premium. Time: half-day. Zero permit paperwork if identical spec.
Upgrading fuel type or configuration
- Gas → Electric or Heat pump: Need a new electrical circuit (electrician cost $400-800), possibly meter upgrade, disposal of old gas connection. Adds $500-1,200 total.
- Electric storage → Heat pump: Usually reuses existing circuit if amps are sufficient; may need new circuit or bigger main fuse. Adds $300-800.
- Anything → Solar HWS: Roof plumbing (typically 15-30m pipe run), tank often relocated to face solar collectors, structural review for roof-mounted tank if applicable. Adds $500-1,000.
How to compare hot water quotes
- Get itemised quotes covering supply, install, disposal of old system, permits, and warranty terms. Reject “supply and install $X flat” quotes.
- Verify plumber’s licence – state licensing authorities (VBA Victoria, QBCC Queensland, Fair Trading NSW). Hot water work is a specific plumbing class.
- Confirm rebate paperwork – who claims the STC / state rebate? Usually the installer, but confirm the discount is on YOUR invoice, not their profit.
- Check warranty specifics – most brands cover the tank/heater 5-10 years, parts 1-3 years, labour 1 year. Solar systems often have separate warranties for collectors (25 years) vs tank (10 years).
- Ask about after-sales servicing – Rheem and Rinnai have national service networks; smaller/imported brands may take weeks to source parts.
→ Use our free quote comparator to spot missing items across 2-3 hot water quotes.
Frequently asked questions
How much does a Rheem hot water system cost in Australia?
Rheem is a mid-range brand covering all system types. Typical 2026 installed prices for a 3-4 person household: Rheem gas storage $1,700-2,300, Rheem gas continuous $2,000-2,600, Rheem electric storage $1,500-2,100, Rheem heat pump $4,000-5,000, Rheem solar HWS $5,000-6,500. Choose “mid-range” in the estimator above for Rheem pricing.
How much does a Rinnai hot water system cost?
Rinnai is best known for gas continuous (Infinity range). Typical 2026 installed prices: Rinnai Infinity 26 gas continuous $2,100-2,700 supplied and installed. Rinnai also does electric continuous and heat pump models. Choose “mid-range” for Rinnai pricing.
How much is a Solahart solar hot water system?
Solahart is the premium AU solar HWS brand. Typical 2026 installed prices: Solahart electric-boosted $6,500-8,500 for a 3-4 person household; Solahart gas-boosted $7,000-9,000. STC + state rebates typically knock $1,500-3,000 off. Choose “premium” in the estimator for Solahart pricing.
Heat pump vs solar HWS – which is better?
Heat pump wins for most households in 2026. Lower install ($4,000-5,500 vs $4,500-6,500 for solar), works regardless of roof aspect, runs happily on solar PV during daytime, better STC rebate. Solar HWS wins only if you have big north-facing roof, no plans for solar PV, and need 20+ year lifespan.
Do I have to replace like-for-like?
No. Any qualified plumber can install any system type in place of your existing one – subject to gas/electrical connection availability and changeover cost above. The most common upgrades are: electric storage → heat pump (biggest running cost savings), gas → heat pump (if you want to go all-electric), gas continuous replacing older gas storage (space savings).
What size hot water system do I need?
Rule of thumb: 40L per person per day. So a 3-4 person household needs a 160-200L tank (or 26L/min continuous). Undersize a tank and you’ll run out during peak use; oversize and you pay for standing losses. Household size in the estimator maps to typical tank sizes.
How long does a hot water system last?
Gas storage tank: 8-12 years. Gas continuous: 12-15 years. Electric storage: 8-12 years. Electric continuous: 10-15 years. Heat pump: 12-15 years. Solar HWS: 15-20 years for tank, 25+ for collectors. Sacrificial anode replacement every 5 years extends most tank lives by 3-5 years.
Related tools
- Plumber Cost Australia – hourly rates and typical HWS install costs
- Electrician Cost Australia – for the circuit upgrade if changing fuel type
- Solar Payback Calculator – the solar PV side of the equation
- Renovation Quote Comparator – paste your hot water quotes for red-flag analysis
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