Heat pump vs gas vs electric hot water system: which is right for your Melbourne home?

Replacing a hot water system is one of those decisions that feels like it should be simple — until you start asking questions. Is a heat pump worth the higher upfront cost? Does gas still make sense when it's being phased out? Will an electric system just run up your power bill? And does solar actually perform through Melbourne's winters?

Every hot water retailer you speak to has a preferred answer. Unfortunately, that answer tends to align suspiciously with whatever system they happen to stock.

We install all four. That matters because it means we have no financial reason to push you toward any one of them. What we do have is 12 months of installation data from Melbourne homes, and a clear view of which systems perform, which underperform, and which choice most homeowners regret.

This guide gives you a straight comparison — upfront cost, running cost, lifespan, rebate eligibility, and Melbourne-specific performance — so you can make a $3,000–$5,000 decision with confidence, not faith.

Types of hot water systems available in Melbourne homes

Melbourne homeowners in 2026 are choosing between four main system types:

Heat pump	Extracts heat from outdoor air to warm water. Highly energy-efficient. The direction the market and the Victorian Government are moving.
Gas	Storage tanks or continuous flow units burning natural gas. Familiar, reliable, and increasingly constrained by regulation. New gas connections are already restricted in residential buildings, and existing systems face mandatory electric replacement from 2027.
Electric	A resistance element heats water in a storage tank. Simple technology with low upfront cost. Running costs are higher than those of a heat pump but lower than many people expect with the right tariff.
Solar	Roof-mounted collectors with a storage tank and a gas or electric booster. High performance in spring and summer. Performance drops in winter, which the booster covers. Requires suitable roof orientation.

Each section below applies the same evaluation framework: how the system works (Feature), what it does better or worse than alternatives (Advantage), and what that means for your household budget and long-term costs (Benefit). The comparison table at the end brings all four together side by side.

Heat pump hot water — how it works, costs, pros and cons

How it works (Feature)

A heat pump hot water system works on the same principle as a reverse-cycle air conditioner. It extracts latent heat from the outdoor air and uses it to warm water in an insulated storage tank — rather than generating heat from scratch. For every unit of electricity consumed, a quality heat pump delivers two to four units of heat energy. That ratio — the Coefficient of Performance, or COP — is what makes heat pumps so efficient.

Most residential heat pump systems pair an outdoor compressor unit with an indoor or outdoor tank, typically ranging from 200 to 400 litres. Installation requires an outdoor space for the compressor, a power connection, and a licensed plumber to complete the water connections.

What it does better (Advantage)

Running costs are 60–75% lower than a conventional electric resistance system, and meaningfully lower than gas for most Melbourne households. On a standard electricity tariff, a quality heat pump system costs approximately $300–$450 per year to run for a family of four. That compares to $600–$900 for an electric storage system and $500–$800 for a gas continuous flow unit.

Heat pumps are the only system type fully aligned with Victoria's electrification direction. From 1 March 2027, gas hot water systems in existing Victorian homes must be replaced with electric alternatives at end-of-life. A heat pump installed now will not require a mandatory swap in 2027. A new gas system installed today will.

Heat pumps also attract the highest government rebate available. Under the Solar Victoria Solar Homes Program, eligible Melbourne homeowners can claim up to $1,400 for a locally manufactured heat pump system. Victorian Energy Upgrade (VEU) discounts may also apply at the point of sale, further reducing the effective cost.

The lifespan advantage is real too. Well-maintained heat pump systems typically last 13–15 years. Electric resistance storage tanks average 10–12 years. Gas continuous flow units run 10–15 years, depending on water quality and service frequency.

What it costs — and what to consider (Benefit)

Upfront cost is the most common objection to heat pumps, and it is a fair one. A quality heat pump system — supplied and installed in Melbourne — typically costs $2,800–$4,500 before rebates. After the Solar Victoria rebate (up to $1,400) and any applicable VEU discount, the effective out-of-pocket cost drops to approximately $1,200–$2,800 for most eligible households. At that price point, running cost savings begin to repay the difference within two to four years.

One consideration Melbourne homeowners raise regularly: noise. The outdoor compressor unit produces a low hum — similar to a reverse-cycle air conditioner — when the system is heating. Quality units operate at 45–55 decibels. Position matters: avoid siting the compressor directly below a bedroom window or on a boundary wall shared with a neighbour. Your licensed plumber will advise on positioning during the site assessment.

For most Melbourne homes — owner-occupied, existing property, household income under $210,000 — a heat pump is the system we would install for a family member. The running cost savings are real, the rebate is substantial, and it is the only system that does not create a mandatory replacement event in 2027.

Gas hot water — storage vs continuous flow

How it works (Feature)

Gas hot water systems come in two configurations. Storage systems heat a tank of water continuously, maintaining a set temperature and replenishing it after use. Continuous flow — also called instantaneous or tankless — heats water on demand as it passes through the unit, with no storage tank required.

Continuous flow gas is the configuration most Melbourne homeowners are replacing today. It delivers unlimited hot water at a consistent temperature and occupies minimal wall space.

What it does well — and where it falls short (Advantage)

Gas continuous flow systems deliver hot water reliably without the upfront cost of a heat pump. Installed cost typically ranges from $1,200–$2,200 for a quality unit in Melbourne. Reliability is strong: these systems are well-understood, widely serviced, and have a clear maintenance path.

The disadvantages are significant and worsening Running costs are increasing. Gas prices in Victoria have risen materially over the past three years. A gas continuous flow system for a family of four currently costs approximately $500–$800 per year, and that figure is likely to increase. The regulatory picture has changed permanently. From 1 March 2027, when a gas hot water system reaches end-of-life in an existing Victorian home, it must be replaced with an electric alternative. A new gas system installed in 2026 carries a known mandatory replacement event within its expected operational lifespan. Gas systems are not eligible for the Solar Victoria hot water rebate. The full system cost is out-of-pocket.

Who gas still makes sense for (Benefit)

Gas continuous flow remains a defensible choice in one specific scenario. That's a rental property where the landlord does not qualify for the Solar Victoria rebate, the existing gas infrastructure is in good condition, and the preference is to defer the capital decision for now. In that context, a like-for-like gas replacement is lower upfront cost with a known future conversion event.

For owner-occupiers who will be living in the property beyond 2027, the economics of a new gas installation are difficult to justify. You are paying full price for a system you will be required to replace within its lifespan, and foregoing rebates that could offset a significant portion of a heat pump's additional upfront cost.

That said, the decision is yours, and we will install the system that is right for your situation. We are not here to tell you gas is wrong. We are here to make sure you understand what you are buying.

Electric hot water — is it still viable in 2026?

How it works (Feature)

An electric storage hot water system uses a resistance element — similar to a kettle element — submerged in an insulated tank to heat water. The element draws electricity continuously or at set times to maintain the temperature. Tank sizes range from 125 to 400 litres for residential use.

This is the simplest hot water technology available. Few components, straightforward maintenance, and a long track record in Australian homes.

What it does well — and where it struggles (Advantage)

Upfront cost is the clearest advantage. An electric storage system installed in Melbourne typically costs $900–$1,800 — the lowest entry point of any system type in this comparison. For a landlord, a rental property, or a household with a constrained upfront budget, electric storage is a real option.

Running costs are the challenge. An electric resistance system heating water from scratch is significantly less efficient than a heat pump performing the same task. For a family of four, annual running costs on a standard electricity tariff are approximately $600–$900 — roughly double that of a heat pump.

There is one important exception. Households on a controlled load or off-peak electricity tariff — where the system heats only during cheaper overnight periods — can reduce electric storage running costs meaningfully. If your property already has a controlled load circuit, electric storage becomes more competitive. Ask your licensed plumber whether your switchboard supports controlled load before ruling it out.

The verdict on electric storage (Benefit)

Electric storage is not a great long-term energy investment, but it is not obsolete. It makes practical sense for a small household (one to two people), a property with a constrained hot water budget, or a situation where a controlled load tariff is already in place.

Importantly, electric storage does not face the same 2027 regulatory constraint as gas. When an electric system reaches end-of-life after 2027, it can be replaced with another electric system — or upgraded to a heat pump to access rebates at that time.

And this brings us to the option that combines the electricity source advantage with a fundamentally different approach to heating efficiency.

Solar hot water — best suited for whom?

How it works (Feature)

A solar hot water system uses roof-mounted collectors — either flat panel or evacuated tube — to capture heat from sunlight and transfer it to an insulated storage tank. On days with sufficient solar radiation, the collectors alone heat the water. A gas or electric booster supplements the solar on cooler or overcast days.

For Melbourne installations, evacuated tube collectors generally outperform flat panels year-round. Evacuated tubes retain heat more effectively in lower-light conditions — a meaningful consideration during Melbourne's autumn and winter months.

What it does well — and where it doesn't (Advantage)

A well-sized solar hot water system can supply 60–80% of a Melbourne household's hot water from solar energy during spring and summer. Annual running costs for a family of four are typically $150–$300, making it one of the lowest-cost systems to run over its lifespan.

The constraints are real. Solar hot water requires a north-facing, unshaded roof area — typically 3–5 square metres. Melbourne homes with east-west roof orientation, significant shading from trees or neighbouring buildings, or roofs already occupied by solar PV panels may not be suitable. Your licensed plumber will assess roof suitability before recommending a solar configuration.

Upfront cost is higher than electric storage and competitive with heat pump: $2,500–$4,000 installed in Melbourne before rebates. Solar hot water systems are eligible for the Solar Victoria rebate — up to $1,000 for most systems, or up to $1,400 for locally manufactured units. Federal Small-scale Technology Certificates (STCs) also apply at the point of sale, providing an additional point-of-sale discount.

Who solar suits (Benefit)

Solar hot water is a strong fit for specific households. Primarily: those with north-facing, unshaded roof space not already committed to solar PV, high daily hot water usage (families of four or more), and a genuine preference for maximising renewable energy use.

It is a weaker fit for smaller households, heavily shaded properties, or homes where roof space is limited or already allocated. Now — with all four options understood — the decision distils to a single question: what does the comparison actually look like when the numbers are side by side?

Comparison table: upfront cost, running cost, lifespan, rebate eligibility

All costs are supplied-and-installed estimates for Melbourne, June 2026. Individual costs vary with product selection, site conditions, and energy tariff. Verify current rebate amounts at solar.vic.gov.au before proceeding.

System	Upfront cost (installed, Melbourne)	Annual running cost (family of 4)	Lifespan	Solar Victoria rebate	2027 gas ban impact
Heat pump	$2,800–$4,500 (after rebates: ~$1,200–$2,800)	$300–$450	13–15 years	Up to $1,400 ✓	Not affected
Gas continuous flow	$1,200–$2,200	$500–$800	10–15 years	Not eligible	Mandatory electric swap at end-of-life
Gas storage	$1,000–$1,800	$500–$750	8–12 years	Not eligible	Mandatory electric swap at end-of-life
Electric storage	$900–$1,800	$600–$900 (lower on off-peak tariff)	10–12 years	Not eligible	Not affected
Solar hot water	$2,500–$4,000 (STCs apply at sale)	$150–$300	15–20 years	Up to $1,400 ✓	Not affected

Not sure which system is right for your Melbourne home?

Book a free assessment — On Time Plumbing recommends the best option for your budget, with no financial incentive to favour any one system type. We install all four. We'll tell you which one makes sense for your home.

Book a free hot water system assessment or Call us today at 1300 110 428.

The 2027 gas ban: why your choice today matters

Confirmed regulation — building.vic.gov.au From 1 March 2027, existing Victorian homes with a gas hot water system that reaches end-of-life must replace it with an electric alternative. This is a confirmed regulation, not a proposal.

What this means for Melbourne homeowners replacing a system today:

• Installing a new gas system in 2026 means installing a system with a mandatory replacement event inside its expected operational lifespan. Gas continuous flow units typically last 10–15 years. A unit installed in 2026 could reach end-of-life before 2036 — well within the window where the 2027 regulation is fully in force.
• Installing a heat pump or solar system in 2026 means your next replacement event happens on your schedule, not the government's — and your current replacement attracts the maximum available rebate.
• For landlords with gas systems in investment properties, the 2027 regulation applies equally. Our guide on landlord plumbing compliance in Victoria covers what this means for property managers planning maintenance budgets beyond 2026.

The regulation is not a reason to panic. It is a reason to make an informed decision now rather than a reactive one later.

Do heat pumps work in Melbourne's cool winters?

Yes — quality heat pump hot water systems perform effectively through Melbourne winters. Melbourne's coldest overnight temperatures typically range from 4°C to 10°C between June and August. Heat pumps with a COP rating of 3.0 or above operate efficiently at temperatures as low as −5°C to −10°C. Melbourne winters are well within that operating range.

The key is choosing a system rated for cool-climate operation. Not every heat pump on the market meets this threshold. In Melbourne's cooler months, we specify units with a minimum COP of 3.0 at 7°C. That threshold ensures the system maintains heating efficiency without leaning on a backup electric element — which would erode the running cost advantage.

Systems we have installed in Melbourne's cooler outer suburbs — including Olinda, Cockatoo, and the Dandenong Ranges, where winter temperatures regularly drop below 5°C overnight — have consistently performed without incident. The question of heat pump suitability for Melbourne is no longer an open one. The right unit, correctly specified, works.

What to ask your plumber: Request the COP rating at 7°C for any heat pump they recommend. A unit that only shows its COP at 20°C or 25°C is not giving you useful cold-weather performance data.

Which brands qualify for the Victorian rebate?

To access the Solar Victoria hot water rebate, the system must appear on Solar Victoria's current approved product list. This list is updated regularly — always verify at solar.vic.gov.au before committing to a specific model.

As of June 2026, brands with qualifying heat pump models include Reclaim Energy, Sanden, Rheem, Dux, Rinnai, and others. Models from Reclaim Energy and Sanden currently meet the locally manufactured criteria, making them eligible for the higher $1,400 rebate where that threshold applies.

For solar hot water systems, qualifying brands include Rheem, Rinnai, Chromagen, and Apricus, among others. Federal STCs apply to solar hot water installations regardless of the Solar Victoria rebate, providing an additional point-of-sale discount via your registered installer.

Gas systems — regardless of brand — are not eligible for the Solar Victoria hot water rebate.

One practical note: the approved product list does not always align with what a given retailer stocks. A brand may have several models, only some of which appear on the list. Confirming the specific model number — not just the brand — against the current approved list is your licensed plumber's responsibility before any installation agreement is signed.

Our recommendation by household type and budget

This is the part most comparison guides avoid. They hedge, list pros and cons, and leave you exactly where you started. We are going to give you a direct answer for each common scenario — because sitting on the fence is not useful when you have a system that needs replacing.

For most Melbourne owner-occupiers: heat pump. The running cost savings over gas or electric resistance are real and sustained. The Solar Victoria rebate, for eligible households, substantially reduces the upfront gap. The 2027 gas mandate is not a reason to panic — but it is a reason to not install gas when you have a financially competitive alternative that avoids the problem entirely. For a family of four in an existing Melbourne home, a heat pump will cost the least over its lifespan in the vast majority of cases.

For households with suitable north-facing roof space and high daily usage: consider solar. Solar hot water has the lowest running costs when sized correctly. If your roof is suitable, your usage is high, and you value maximising renewable energy use, solar is a strong long-term investment. For smaller households, the payback period is less favourable, and a heat pump becomes the stronger choice.

For rental properties where the landlord does not qualify for the rebate: gas continuous flow is still defensible. Not every landlord will access the Solar Victoria rebate. For a rental property where the existing gas infrastructure is sound, and the landlord's priority is the lowest upfront cost, a like-for-like gas replacement is a reasonable short-term decision. The caveat: a conversion to electric will be required within the system's lifespan under current Victorian regulations.

For very small households or constrained budgets: electric storage. A single person or couple with access to a controlled load electricity tariff can run an electric storage system cheaply. The upfront cost is the lowest of any system. It is not the optimum long-term choice, but it is legitimate for a specific set of circumstances.

What we do not recommend A new gas system for an owner-occupier who plans to stay in the property beyond 2030. The combination of rising gas tariffs, no access to rebates, and a mandatory future conversion event makes it the least cost-effective choice for long-term owner-occupiers in Melbourne.

You now have a clear picture of what each system costs, how it performs in Melbourne's climate, and which scenario each one fits. That is more than most Melbourne homeowners have going into this decision — and it puts you in a position to choose based on evidence, not on which plumber you happened to call first.

FAQ

Is a heat pump better than gas hot water?

For most Melbourne owner-occupiers in 2026, yes. Heat pumps run at 60–75% lower cost than electric resistance systems, and are cheaper than gas for most households on current energy tariffs. They qualify for up to $1,400 in government rebates and are not affected by Victoria's 2027 gas hot water mandate. The main objection — higher upfront cost — is substantially offset by rebates for eligible households, and repaid through running cost savings within two to four years for the average Melbourne family.

What is the cheapest hot water system to run in Australia?

Solar hot water has the lowest annual running costs when conditions are right — typically $150–$300 per year for a family of four. Heat pump hot water systems are the most cost-effective option for homes where solar installation is not suitable, running at approximately $300–$450 per year. Both significantly outperform gas and electric resistance systems on an ongoing running cost basis.

Are heat pumps worth it in Melbourne?

Yes, for most Melbourne homes. Melbourne's climate is well within the operating range of quality heat pump systems — overnight temperatures during winter rarely fall below the threshold at which heat pump efficiency drops materially. A heat pump with a COP of 3.0 or above at 7°C operates efficiently year-round in Melbourne. The combination of lower running costs, government rebates, and alignment with Victoria's electrification direction makes heat pumps a sound investment for Melbourne owner-occupiers.

How long do heat pump hot water systems last?

A well-maintained residential heat pump typically lasts 13–15 years. This compares to 10–12 years for electric resistance storage systems and 10–15 years for gas continuous flow units. Solar hot water systems have the longest lifespan at 15–20 years for the collector component. Heat pump longevity is supported by annual servicing — primarily cleaning the air filter and inspecting the refrigerant circuit.

What hot water system qualifies for the Victorian rebate?

Heat pump and solar hot water systems approved by Solar Victoria qualify for the Solar Homes Program rebate — up to $1,000 for standard approved systems and up to $1,400 for locally manufactured products. Gas systems do not qualify. Electric resistance storage systems do not qualify. The specific model must appear on Solar Victoria's current approved product list, which is updated regularly and can be verified at solar.vic.gov.au. Your registered installer confirms model eligibility before any installation agreement is signed.

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Disclaimer: Cost estimates are based on Melbourne market pricing as at June 2026 and will vary with product selection, site conditions, and energy tariffs. Rebate amounts and eligibility criteria are subject to change — always verify current terms at solar.vic.gov.au and energy.vic.gov.au before proceeding. Regulatory information is sourced from building.vic.gov.au and is accurate as at the date of publication.