Hot Water System Types in Melbourne: Which One Should You Choose in 2026?
Published 14 June 2026 · 8 min read
When a hot water system dies, most Melbourne homeowners replace it with the same type they already had. That is often the fastest option, but not always the cheapest or the smartest one. The four main system types are electric storage, gas storage, heat pump, and instantaneous (continuous flow). They have different upfront costs, running costs, and suitability depending on your home's setup.
This guide sets out what each system actually costs to buy and run in Melbourne in 2026, what rebates are available, and which type suits which household.
The four system types at a glance
| System type | Upfront install cost | Typical annual running cost | Best for |
|---|---|---|---|
| Electric storage | $1,400–$2,800 | $900–$1,400 | Households with solar or off-peak tariff |
| Gas storage | $1,800–$3,800 | $400–$700 | Homes with existing gas connection |
| Heat pump | $3,000–$5,500 | $300–$600 | Households wanting lowest running costs |
| Instantaneous (gas) | $1,200–$3,500 | $350–$650 | Smaller households, limited space |
Price ranges based on real south-east Melbourne job data. Your plumber quotes after assessing the actual job. If something unexpected is uncovered during the work, they'll pause, explain, and re-quote before continuing.
Need a hot water system replaced today? Call 0450 158 124. The VicPlumbers network covers south-east Melbourne with VBA-licensed plumbers available 24/7.
Electric storage systems
Electric storage systems heat water using an element inside an insulated tank, typically 125–400 litres. They are the most common system in south-east Melbourne's older housing stock, particularly in homes built before the 1990s when gas connections were not universal.
Upfront cost: $1,400–$2,800 installed, depending on tank size and location.
Running cost: The highest of the four types on a standard tariff, roughly $900–$1,400 per year for a typical household. The main reason is that resistive heating converts electricity to heat at 1:1 efficiency, which is expensive compared to gas or heat pumps.
Where electric storage makes sense:
- Homes with rooftop solar: setting the hot water system to heat during the day uses excess generation rather than grid electricity, which can cut running costs to near zero.
- Homes on an off-peak tariff: some Melbourne households still have dedicated off-peak circuits that charge the hot water system overnight at a lower rate.
- Rental properties or low-budget replacements where upfront cost is the primary constraint.
Where it does not:
A straight electric storage replacement in a home without solar or off-peak is increasingly hard to justify on running costs alone. Over a 10-year system life the difference in energy bills between electric and heat pump can exceed $5,000.
Gas storage systems
Gas storage systems work on the same tank principle as electric but use a gas burner to heat the water. They are faster to recover after a big draw than electric systems and cheaper to run on the current gas-electricity price spread.
Upfront cost: $1,800–$3,800 installed. The higher cost versus electric reflects the gas burner and flue components.
Running cost: $400–$700 per year for a typical household, roughly half the cost of electric storage at standard tariff rates.
Where gas storage makes sense:
- Homes with an existing natural gas connection: the marginal cost of adding hot water to an existing gas line is low.
- Larger households with high hot water demand: gas systems recover faster than electric, so a family of five is less likely to run out.
Where it does not:
Homes without a gas connection face the additional cost of running a gas line, which can add $1,000–$3,000 to the install depending on distance from the street supply. At that point the economics shift toward heat pump. Gas prices have also risen faster than electricity in recent years, narrowing the running cost advantage over time.
Heat pump systems
Heat pump hot water systems extract heat from the surrounding air and use it to warm the water, in the same way a reverse-cycle air conditioner heats a room. They are three to four times more energy-efficient than electric storage. For every 1 kWh of electricity they use, they deliver 3–4 kWh of heat.
Upfront cost: $3,000–$5,500 installed. The higher cost reflects the refrigerant circuit and compressor.
Running cost: $300–$600 per year, the lowest of the four types on grid electricity.
Rebates available in 2026:
Two rebate mechanisms apply to heat pump installs in Victoria:
- Small-scale Technology Certificates (STCs): federal scheme, worth approximately $500–$1,000 on a typical residential heat pump depending on your climate zone and system size. Most installers discount the price at point of sale and claim the STCs themselves.
- Victorian Energy Upgrades (VEU): state scheme, worth approximately $300–$800 depending on the system and your postcode. Ask your plumber whether the system they are quoting is VEU-registered.
Combined, rebates can reduce the effective purchase price by $800–$1,500, which significantly improves the payback calculation versus electric storage.
Where heat pump makes sense:
- Households replacing an electric storage system who plan to stay in the property for five or more years. The running cost saving typically pays back the price premium within four to six years.
- Homes with solar where the system can be scheduled to run during generation hours.
Where it does not:
Heat pumps draw air from outside and work less efficiently in very cold conditions. In Melbourne's climate this is rarely a problem, but a unit installed in a small, enclosed space like an internal laundry may underperform. The compressor also makes noise, similar to an air conditioner, so placement matters in attached or semi-detached homes.
Instantaneous (continuous flow) gas systems
Instantaneous systems heat water on demand rather than storing it. A gas burner fires when you open a tap and heats water as it flows through a heat exchanger. There is no tank.
Upfront cost: $1,200–$3,500 installed, depending on flow rate capacity and whether a new gas line or flue is required.
Running cost: $350–$650 per year for a typical household, similar to gas storage, with the advantage that you only heat water you actually use.
Where instantaneous makes sense:
- Smaller households or single occupants with modest hot water demand.
- Properties with limited space: no tank means the unit mounts on a wall.
- Homes where simultaneous hot water demand is low: instantaneous systems can struggle if multiple showers, a dishwasher, and a washing machine all run at once.
Where it does not:
Higher simultaneous demand can overwhelm a smaller unit. Sizing matters, an undersized unit will deliver lukewarm water during peak use. A good plumber will calculate the required flow rate before quoting. Instantaneous systems also require a larger gas supply line than storage systems in some configurations, which can add to install cost.
What about electric instantaneous?
Electric instantaneous systems exist but are rarely the right choice for whole-home hot water in Melbourne. The instantaneous heating load requires very high electrical draw, typically 18–27 kW, which demands upgraded wiring and a large circuit breaker. For point-of-use applications like a bathroom a long distance from the main system, a small electric instantaneous unit can make sense. For whole-home replacement, gas instantaneous or heat pump are almost always better options.
The transition away from gas
Victoria has signalled a long-term transition away from natural gas in residential buildings. New homes approved under the updated NCC are increasingly gas-free. If your home already has gas and the connection is working, a gas system replacement is still a straightforward and cost-effective option. But if you are building or doing a major renovation, or if your gas connection is aging and needs replacement, it is worth factoring in the direction of policy travel.
Heat pump systems run on electricity only and are compatible with future all-electric homes. They also benefit from any improvement in the electricity grid's renewable share, whereas gas running costs are entirely tied to gas prices.
Which system is right for you?
| Your situation | Recommended type |
|---|---|
| Have solar or off-peak tariff | Electric storage or heat pump |
| Have gas connection, want lowest upfront cost | Gas storage |
| Want lowest running costs, staying 5+ years | Heat pump |
| Small household, limited space, have gas | Instantaneous gas |
| No gas connection, want to avoid running it | Heat pump |
| Rental property, minimise upfront cost | Electric storage |
Do I need a licensed plumber for a hot water replacement?
Yes. Hot water system replacement is regulated plumbing work in Victoria. A VBA-licensed plumber is required for the connection and commissioning regardless of system type. Gas systems additionally require a plumber with a gasfitting licence endorsement.
The plumber must issue a Certificate of Compliance on completion. Keep this, you need it for insurance claims and it becomes relevant when you sell the property.
For heat pump systems eligible for VEU rebates, the installer must be accredited under the VEU program. Confirm this before booking.
Need a hot water system replaced in south-east Melbourne?
VicPlumbers connects homeowners across south-east Melbourne with VBA-licensed plumbers experienced in all four system types. Your plumber quotes after assessing the job, before any work begins. If something unexpected comes up during the install, they pause, explain, and re-quote before continuing.
Call 0450 158 124 or request a callback at vicplumbers.com.au.
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