Gas Hot Water System Price: Australian Buyer’s Guide for Supply, Replacement and Running Costs

Gas hot water system prices can vary widely depending on the brand, system type, flow rate, gas type, household size and whether you are buying supply-only or choosing a supplied-and-installed option where available.

For many Australian homes, gas hot water is compared because it can provide strong hot water performance, compact outdoor units and continuous flow options for households that already have natural gas or LPG. The most common modern gas option is an instant gas hot water system, also called a continuous flow gas hot water system, which heats water as it is used instead of storing it in a large tank.

The important thing is to compare the total replacement cost, not just the unit price. A gas hot water replacement may also involve valves, gas fitting, electrical connection, pipework changes, drainage, access issues, old unit removal, disposal and compliance upgrades depending on the property.

Installed Today supplies a range of gas hot water systems, along with broader hot water systems, electric hot water systems and heat pump hot water systems for customers comparing replacement options.

Quick answer: how much does a gas hot water system cost?

The price of a gas hot water system depends on whether you are looking at the product only or the total replacement.

The main cost parts are:

For supply-only customers, the product price is not the full installed cost. For supplied-and-installed options in eligible Brisbane and Gold Coast service areas, check the product page carefully to see what is included and what may be an add-on.

What affects gas hot water system price?

Gas hot water pricing depends on several factors. Two systems may look similar online but have different requirements once installed at the property.

The main price factors include:

• Whether the system is natural gas or LPG

• Whether it is continuous flow gas or gas storage

• Flow rate in L/min

• Brand and model

• Number of bathrooms

• Number of people in the home

• Whether the replacement is like-for-like

• Whether the unit is being moved

• Gas pipe sizing

• Water pressure

• Existing valve condition

• Outdoor location and clearances

• Electrical connection for continuous flow models

• Access to the installation area

• Whether old unit removal is required

• Whether compliance upgrades are needed

The cheapest gas hot water unit is not always the cheapest final replacement. If the system does not suit the property, extra work may be needed.

Gas hot water system unit price vs installed price

When comparing gas hot water systems, separate the unit price from the installed price.

Unit price

The unit price is the cost of the hot water system itself. This is what supply-only customers focus on when they already have their own licensed installer arranged.

Installed price

The installed price includes the product plus the work required to remove or disconnect the old system, connect the new system and complete the required plumbing, gas fitting, valves, drainage and compliance items.

Installed pricing can vary because every property is different. A straightforward like-for-like replacement in the same location is usually simpler than changing system type, moving the unit or upgrading gas pipework.

Supply-only gas hot water systems

Supply-only means you buy the product and arrange your own licensed installer.

This can suit:

• Customers who already have a plumber or gas fitter arranged

• Builders and renovators

• Landlords working through a property manager

• Customers replacing like-for-like systems

• Customers outside supplied-and-installed service areas

• Customers who want to compare products online before ordering

Supply-only product pricing generally does not include:

• Installation labour

• Gas fitting

• Electrical work

• Pipework changes

• Valves

• Drainage

• Old unit removal

• Disposal

• Gas pipe upgrades

• Compliance upgrades

• Difficult access

• Stands, brackets or mounting changes

Before ordering supply-only, confirm the selected model, gas type, flow rate and installation requirements with your licensed installer.

Supplied and installed gas hot water systems

Installed Today offers supplied-and-installed options on selected products in eligible Brisbane and Gold Coast service areas where shown.

A supplied-and-installed option may suit customers who want a more complete replacement pathway instead of ordering the product only.

Before ordering, check:

• Whether installation is available for your address

• What the listed installation includes

• Whether old unit removal is included or an add-on

• Whether disposal is included or an add-on

• Whether valves are included or extra

• Whether pipework changes are included or extra

• Whether gas upgrades are included or extra

• Whether electrical work is included or extra

• Whether the replacement is like-for-like

• Whether the selected model matches natural gas or LPG

Do not assume every replacement includes every possible site requirement. Product pages and selected add-ons should be checked carefully.

Types of gas hot water systems

The main gas hot water options are:

1. Continuous flow gas hot water systems

2. Gas storage hot water systems

3. Solar hot water with gas boosting

Each type has different pricing, installation and performance considerations.

Continuous flow gas hot water system price

Continuous flow gas hot water systems are often called instant gas hot water systems. They heat water as it passes through the unit instead of storing hot water in a tank.

They are commonly available in flow rates such as:

• 16 L/min

• 20 L/min

• 26 L/min

A smaller 16 L/min unit may suit a compact home or 1 bathroom property, while a 26 L/min unit is commonly compared for family homes and 2 bathroom properties. The right size depends on gas supply, water pressure, simultaneous use and household demand.

You can compare options in the instant gas hot water systems collection.

Gas storage hot water system price

Gas storage hot water systems store heated water in a tank. They can suit homes already using gas storage where a like-for-like replacement is practical.

Gas storage pricing depends on:

• Tank capacity

• Brand

• Natural gas or LPG

• Indoor or outdoor model

• Existing location

• Valve requirements

• Pipework condition

• Access

• Whether the old tank needs removal

Gas storage may still suit some homes, but many customers also compare continuous flow gas when replacing an older gas storage system.

Solar hot water with gas boosting

Some solar hot water systems use gas boosting to provide backup heating when solar gain is not enough.

These systems can be more complex because they may involve:

• Roof collectors

• Storage tank

• Gas booster

• Roof access

• Booster type

• Plumbing connections

• Existing solar condition

• Controller or sensor components

• Site-specific replacement requirements

Solar hot water can suit some properties, but it is not always the simplest replacement. If an older solar system has failed, compare whether another solar system, heat pump, electric storage or gas continuous flow system is the best fit.

Natural gas vs LPG price considerations

Gas hot water systems must match the property’s fuel type. Natural gas and LPG are not interchangeable.

Before ordering, check whether your property uses:

• Natural gas from a street gas supply

• LPG from gas bottles

Natural gas and LPG models may have different product codes, availability and installation requirements. Choosing the wrong gas type can delay installation and create compliance problems.

Check the label on your existing unit, your gas meter or LPG bottle setup, and ask your licensed gas fitter to confirm before ordering.

What size gas hot water system do you need?

Gas continuous flow systems are usually sized by litres per minute, not tank capacity.

As a general guide:

A larger L/min rating can cost more, but it may be necessary for homes with higher demand. However, the property’s gas supply must support the selected unit. A large unit connected to undersized gas pipework may not perform as expected.

Why flow rate affects price

Flow rate matters because it affects how much hot water the unit can produce.

A higher-flow model may cost more because it is designed to support greater hot water demand. This can be important for:

• Two bathroom homes

• Family households

• Homes with teenagers

• Back-to-back showers

• Higher-flow shower heads

• Properties where two outlets may run at once

• Rental or Airbnb properties

For a small home with one shower, paying for a larger unit may not be necessary. For a family home, choosing too small can lead to poor performance.

Gas hot water installation cost factors

Gas hot water installation can vary because every site is different.

Important installation cost factors include:

• Like-for-like replacement or system change

• Same location or new location

• Gas pipe sizing

• Water pipework changes

• Valve requirements

• Electrical connection

• Wall mounting

• Outdoor clearances

• Drainage

• Access

• Old unit removal

• Disposal

• Compliance upgrades

• Natural gas or LPG setup

A simple replacement of an existing external continuous flow gas unit may be more straightforward than converting from electric storage to gas continuous flow.

Why gas pipe sizing matters

Gas pipe sizing can affect both installation cost and system performance.

A larger continuous flow gas unit may require more gas supply than the old unit. If the existing gas pipework is undersized, the system may not work properly or the installation may require upgrades.

This is especially important when:

• Upgrading from a smaller unit to a 26 L/min model

• Switching from gas storage to continuous flow gas

• Adding other gas appliances

• Changing from electric to gas

• Using LPG bottle supply

• The existing gas line is old or long

A licensed gas fitter should confirm suitability before installation.

Does gas hot water need electrical work?

Many continuous flow gas hot water systems need an electrical connection for ignition, controls and operation.

Even though the unit uses gas to heat the water, it may still need power. This can affect replacement cost if the existing system did not have a suitable power point or electrical setup nearby.

Electrical work must be completed by a licensed electrician where required.

Gas hot water valves and add-ons

A gas hot water replacement may require valves and fittings to operate safely and comply with current requirements.

Common items may include:

• Tempering valve

• Isolation valves

• Pressure limiting valve

• Duo valve

• PTR valve where applicable

• Non-return valve

• Drain line

• Gas isolation valve

• Pipework fittings

• Controller wiring where selected

Some of these items may already exist and be suitable. Others may need replacement or upgrading depending on the property and selected system.

Old unit removal and disposal

The cost of replacing a gas hot water system may also include old unit handling.

Depending on the order and installer, old unit removal and disposal may be included, optional or separate.

Before ordering, check whether the old system needs:

• Disconnection

• Removal from wall or base

• Safe handling

• Disposal

• Access through narrow side paths

• Extra labour due to weight or location

This is especially important for older gas storage tanks, roof-connected solar systems or units in tight spaces.

Gas hot water running costs

Gas hot water running costs depend on the system, fuel type, household use and local tariffs.

Factors that affect running costs include:

• Natural gas or LPG pricing

• Number of people in the home

• Number of showers per day

• Shower length

• Shower head flow rate

• Number of bathrooms

• System efficiency

• System size

• Hot water temperature settings

• Pipe length between unit and outlets

• Maintenance condition

• Whether multiple outlets are used together

A gas continuous flow system may avoid storing a full tank of hot water, but it still uses gas when hot water is running. A poorly sized or poorly maintained system may cost more to run than expected.

Are gas hot water systems cheaper to run than electric?

Gas hot water can be cheaper to run than some electric storage systems in some homes, but this is not guaranteed for every property.

The comparison depends on:

• Gas tariff

• Electricity tariff

• Natural gas or LPG

• System efficiency

• Household demand

• Whether solar power is available

• Whether heat pump hot water is an option

• Existing services

• Installation cost difference

For homes with rooftop solar, a heat pump or electric storage setup may be worth comparing. For homes already connected to gas, continuous flow gas may be a strong option.

The best comparison is based on your property, not a general promise of savings.

Gas hot water vs electric storage price

Electric storage hot water systems often have straightforward replacement options where the home already has electric hot water. Gas continuous flow can be more compact and may suit homes with gas supply, but installation may be more involved if gas pipework or electrical connection is required.

If your current system is electric and the home has no gas, changing to gas may add significant extra work. If your current system is already gas, a gas replacement may be more practical.

Gas hot water vs heat pump price

Gas continuous flow and heat pump hot water are often compared by homeowners wanting to move away from standard electric storage.

Gas continuous flow may suit homes with existing gas supply and a suitable external location.

Heat pump hot water may suit homes that want an efficient electric option and have the right outdoor location, airflow and drainage.

The right choice depends on existing services and long-term plans.

Rebates and incentives

Rebates, incentives and energy schemes can change by state, product type, date and eligibility rules.

Before choosing a system based on a rebate, check:

• Whether the product is eligible

• Whether your property is eligible

• Whether the installer must be accredited

• Whether the rebate applies in your state

• Whether the rebate is applied upfront or claimed later

• Whether the scheme is still open

• Whether paperwork is required

Do not rely on old rebate information when ordering a hot water system. Confirm current eligibility before purchase.

Maintenance and long-term cost

Gas hot water system cost is not only about purchase and installation. Maintenance also affects long-term value.

Gas systems may need periodic servicing to check:

• Burner operation

• Gas connections

• Water filters

• Controllers

• Error codes

• Flue or clearances

• Water flow

• Leaks

• General system condition

Maintenance should be completed by appropriately licensed professionals.

A well-maintained system may last longer and perform more consistently than a neglected one. Poor maintenance, poor water quality, incorrect installation or unsuitable sizing can all reduce system life.

How long does a gas hot water system last?

The life of a gas hot water system depends on the brand, model, installation quality, water quality, maintenance, usage and environment.

A system may need replacement earlier if:

• It is heavily used

• It is exposed to harsh weather

• Water quality is poor

• It has not been serviced

• It is incorrectly installed

• Parts fail repeatedly

• The tank is leaking

• It no longer meets household demand

For gas storage systems, tank condition matters. For continuous flow systems, internal components, water quality and service history can affect life.

Best gas hot water system for a 1 bathroom home

A small 1 bathroom home may compare a 16 L/min continuous flow gas hot water system where gas supply is suitable.

This may suit:

• 1–2 people

• One shower

• Smaller homes

• Granny flats

• Units or townhouses with gas

• Low-to-moderate hot water demand

If the home has higher demand, longer showers or future rental use, a 20 L/min model may be worth comparing.

Best gas hot water system for a 2 bathroom home

A 2 bathroom home commonly compares a 26 L/min continuous flow gas system.

This may suit:

• Families

• 3–5 people

• Homes with two bathrooms

• Back-to-back showers

• Higher hot water use

• Properties replacing an existing 26 L/min unit

However, suitability depends on gas supply, water pressure and whether two showers may run at the same time.

Best gas hot water system for rental properties

For rental properties, gas hot water should be simple, reliable and correctly sized for likely tenant demand.

A rental may need more flexibility than the current tenant requires. A small system that works for one tenant may not suit the next household.

For gas rentals, check:

• Natural gas or LPG

• Existing gas setup

• Number of bathrooms

• Likely occupancy

• Whether the system is easy for tenants to use

• Whether LPG bottle management is practical

• Whether the system is correctly sized

If the property often changes tenants, avoid undersizing purely to reduce upfront cost.

Best gas hot water system for Airbnb and short-stay properties

Short-stay properties should be sized for maximum guest occupancy, not average use.

A gas continuous flow system may suit Airbnb and short-stay homes where:

• Gas supply is suitable

• The system is correctly sized

• Guests may shower back-to-back

• External location is compliant

• Operation is simple

• LPG supply is well managed if applicable

For short-stay properties, hot water complaints can affect guest experience, so choosing the smallest model may be risky.

What to check before ordering gas hot water online

Before ordering a gas hot water system, check:

• Current system type

• Current brand and model

• Current L/min rating or tank capacity

• Natural gas or LPG

• Indoor or outdoor location

• Number of bathrooms

• Number of people in the home

• Whether two showers run at once

• Existing gas pipe size if known

• Water pressure issues

• Electrical connection availability

• Valve condition

• Drainage

• Access to the unit

• Whether old unit removal is needed

• Whether supply only or supplied and installed is required

This reduces the risk of ordering a system that is the wrong gas type, wrong size or unsuitable for the property.

Common mistake: comparing only the unit price

The unit price is only one part of the gas hot water system cost.

A cheaper unit may not be cheaper overall if it requires:

• Gas pipe upgrades

• Extra valves

• Electrical work

• Pipework changes

• Drainage changes

• Controller work

• Compliance upgrades

• Difficult access labour

Always compare the complete replacement pathway.

Common mistake: choosing the wrong gas type

Natural gas and LPG models are different. Ordering the wrong one can delay installation and create extra cost.

Before ordering, confirm the gas type from the existing unit label, meter, LPG bottle setup or licensed gas fitter.

Common mistake: choosing the wrong flow rate

A 16 L/min unit may be cheaper than a 26 L/min unit, but it may not suit a family home.

At the same time, a 26 L/min unit may not be necessary for a small one-bathroom home. Match the unit to the household and property.

Common mistake: assuming gas is always cheaper than electric

Gas can be a strong option for homes already connected to natural gas or LPG, but running costs depend on tariffs, usage and system efficiency.

Homes with solar power or suitable outdoor space may also compare heat pump hot water. Homes without gas may find electric storage simpler and cheaper to replace upfront.

Common mistake: replacing an undersized system with the same model

If your old gas hot water system never kept up, replacing it with the same size may continue the problem.

Consider upgrading if:

• More people now live in the home

• A second bathroom has been added

• The property has become a rental

• Guests use the home

• Two showers run close together

• The old unit had poor flow

• The system was too small from the start

The replacement should suit current demand, not just the old product label.

Gas hot water prices in Brisbane and Gold Coast

For eligible Brisbane and Gold Coast service areas, Installed Today offers supplied-and-installed options on selected hot water systems where shown.

Common gas hot water replacement options include:

• 16 L/min continuous flow gas systems

• 20 L/min continuous flow gas systems

• 26 L/min continuous flow gas systems

• Natural gas models

• LPG models

• Selected Rinnai, Rheem and other brand options

Check the product page carefully for current product pricing, installation availability and add-ons. Availability, inclusions and pricing can vary by product and service area.

Gas hot water supply-only for other Australian metro areas

Installed Today also supports supply-only ordering across major Australian metro areas for customers who have their own licensed installer arranged.

This can suit customers outside eligible supplied-and-installed areas who want to compare and order gas hot water products online.

Before ordering, confirm:

• The product can be delivered to your location

• Your installer approves the selected model

• Gas type is correct

• The unit size suits the home

• Installation requirements are understood

• Any local compliance requirements are covered by your installer

Final recommendation

Gas hot water system price is not just the cost of the unit. The real cost depends on the system type, flow rate, natural gas or LPG, installation requirements, valves, gas supply, access and whether the replacement is like-for-like.

For small homes, a 16 L/min gas continuous flow system may be enough. For moderate demand, 20 L/min may be worth comparing. For family homes and many 2 bathroom properties, 26 L/min is commonly compared, provided the gas supply and water pressure are suitable.

If your home already has gas hot water, a like-for-like replacement may be the simplest option. If you are changing from electric to gas, confirm the total work required before ordering.

To compare current options, browse instant gas hot water systems or view the full Installed Today hot water systems range.

Long-tail FAQs

How much does a gas hot water system cost?

Gas hot water system cost depends on the brand, model, flow rate, gas type and whether you are buying supply-only or supplied-and-installed where available. The total cost may also include valves, gas fitting, pipework, electrical work, drainage, old unit removal and compliance upgrades.

Is a gas hot water system cheaper than electric?

Gas hot water may be cheaper to run than some electric storage systems in some homes, but it depends on gas prices, electricity tariffs, usage, system efficiency and whether the home has solar power or heat pump suitability.

What is the cheapest gas hot water system?

The cheapest gas hot water system is usually a smaller or more basic model, but it may not suit every home. A 16 L/min unit may cost less than a 26 L/min unit, but it may be undersized for a family home.

What size gas hot water system do I need?

A small 1 bathroom home may compare 16 L/min, moderate homes may compare 20 L/min, and family homes or many 2 bathroom properties may compare 26 L/min. The right size depends on gas supply, water pressure and simultaneous hot water use.

Is natural gas the same as LPG for hot water?

No. Natural gas and LPG systems are different and must match the property’s fuel type. Always choose the correct model before ordering.

Does gas hot water need electricity?

Many continuous flow gas hot water systems need electricity for ignition, controls and operation. If there is no suitable power point nearby, electrical work may be required.

Can I replace electric hot water with gas hot water?

You may be able to, but changing from electric to gas can involve gas pipework, electrical work, water pipework changes, valves, drainage and compliance upgrades. Confirm requirements with a licensed installer before ordering.

Is instant gas hot water better than gas storage?

Instant gas hot water can be compact and heat water on demand, while gas storage keeps hot water in a tank. The better option depends on the existing setup, household demand, space and installation requirements.

Are rebates available for gas hot water systems?

Rebates and incentives can change by state, product type and eligibility rules. Check current rebate details before choosing a system based on an incentive.

Does supply-only include installation?

No. Supply-only generally means the product is supplied only. Installation, valves, gas work, electrical work, pipework changes, drainage, old unit removal, disposal and compliance upgrades are separate unless clearly shown as included.