Instant Gas Hot Water Systems Supplied & Installed From $1,199
Compare continuous-flow gas systems and installed options, then refine the right flow rate for your bathrooms, simultaneous use and existing unit.
Find The Right Instant Gas System
We’ll size the system around simultaneous hot water demand, compare it with your existing unit, then guide you into the most suitable specialist range.
Why homeowners choose JR Gas & Water
Real stories from instant gas hot water system homeowners who’ve experienced fast installs, expert advice, and 5-star service with JR Gas & Water.
Browse Gas Hot Water Systems by Size & Features
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Book an onsite inspection and one of our plumbers can inspect your existing hot water system, check the installation requirements and talk you through the replacement options available for your home.
Ideal if you would prefer to have your existing system inspected and discuss the available options with a plumber before choosing your replacement.
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Instant Gas Hot Water Systems Brisbane & Gold Coast
Instant gas hot water systems, also known as continuous flow gas hot water systems, heat water only when a hot tap is opened. There is no storage cylinder, making them a compact option for Brisbane and Gold Coast homes wanting continuous hot water without keeping a tank heated between uses.
JR Gas & Water supplies, replaces and installs continuous flow gas hot water systems throughout Greater Brisbane, the Gold Coast, Logan, Ipswich, Redlands, Moreton Bay and surrounding South East Queensland areas. Compare current instant gas systems and installed pricing above, or use our selector to choose a suitable flow rate based on bathrooms, simultaneous hot water use and the existing system.
Current available instant gas hot water systems in this collection have advertised starting prices from to . Use the selector and installation options above to confirm the supplied-and-installed price for your property.
Instant gas is sized differently from storage hot water. Instead of choosing a tank capacity in litres, continuous flow systems are compared by the amount of heated water they can deliver per minute under defined operating conditions.
How Does an Instant Gas Hot Water System Work?
A continuous flow gas water heater detects water moving through the unit when a hot tap is opened. The burner ignites and transfers heat into the flowing water before it leaves the unit and travels to the outlet.
1. Hot Tap Opens
Water begins flowing through the continuous flow hot water system.
2. Flow Is Detected
The system detects sufficient water flow and begins the heating sequence.
3. Gas Burner Operates
The burner supplies the heat required to raise the incoming water towards the required outlet temperature.
4. Water Is Heated
Water passes through the heat exchanger and absorbs heat as it moves through the unit.
5. Hot Water Reaches the Home
The heated water travels through the property's hot water pipework to the open outlet.
6. Heating Stops
When hot water flow stops, the burner shuts down rather than keeping a storage tank continuously heated.
What Does 16L, 20L, 26L or 32L Instant Gas Mean?
The litre rating on a continuous flow gas hot water system describes its hot water flow capacity under specified test conditions. A 26L class system, for example, may be capable of heating approximately 26 litres of water per minute at the temperature rise used for its rating.
This is different from a 250L electric storage system, where the litres describe the amount of water stored in the tank. An instant gas unit does not contain 26 litres of stored hot water. The number describes flow performance.
Why Temperature Rise Matters When Sizing Instant Gas
Continuous flow capacity depends on how much the incoming water needs to be heated. Raising relatively warm incoming water by a smaller amount requires less burner output than taking colder incoming water to the same final temperature.
This is why a manufacturer's maximum litres-per-minute figure should be read together with the temperature rise used to rate that output. The available flow at the required outlet temperature can change as incoming water temperature changes.
| Situation | Temperature Rise Required | Effect on Available Hot Water Flow |
|---|---|---|
| Warmer incoming water | Lower | The system can generally deliver a higher flow at the target temperature |
| Colder incoming water | Higher | More burner energy is required for each litre of water |
| Multiple outlets running | Same temperature target, greater total flow | Total system capacity is shared across the active outlets |
What Size Instant Gas Hot Water System Do I Need?
The best continuous flow size is based primarily on simultaneous hot water demand. Start with the number of showers or other hot outlets likely to run together, then confirm the required flow, gas supply, water pressure and installation conditions.
10L–13L Instant Gas
Compact continuous flow systems best suited to low hot water demand, granny flats and many one-bathroom applications where multiple hot outlets are unlikely to operate simultaneously.
Compare 10L–13L instant gas systems →16L Instant Gas
A practical one-bathroom category for homes wanting more flow than compact systems without stepping immediately into larger family continuous flow units.
Compare 16L instant gas systems →20L Instant Gas
A useful medium-demand category and a common starting point for homes wanting additional simultaneous-flow capacity beyond smaller 16L systems.
Compare 20L instant gas systems →26L Instant Gas
One of the strongest all-round family categories for homes needing higher continuous flow and greater ability to supply simultaneous hot water outlets.
Compare 26L instant gas systems →32L Instant Gas
High-capacity residential continuous flow for larger homes and households with heavier simultaneous hot water demand.
Compare 32L instant gas systems →Powerless / Hydropower Gas
Selected compact continuous flow systems can operate without a normal mains power point, making them especially useful for suitable like-for-like replacements.
Compare hydropower gas systems →Natural Gas vs LPG Instant Gas Hot Water
Continuous flow gas hot water systems can be available in natural gas and LPG versions depending on the model. The correct appliance must be selected for the fuel supplied to the property.
| Comparison | Natural Gas | LPG |
|---|---|---|
| Fuel Supply | Generally reticulated natural gas | Usually LPG cylinders or another suitable LPG supply |
| Appliance | Natural-gas compatible model required | LPG-compatible model required |
| Availability | Depends on natural gas network availability | Can suit properties without reticulated natural gas |
| Running Cost | Depends on current gas tariff and consumption | Depends on LPG price, cylinder setup and consumption |
| Best Replacement | Often simplest where natural gas already serves the old unit | Often simplest where a suitable LPG setup already exists |
50°C vs 60°C Instant Gas Hot Water Systems
Many continuous flow ranges are available in different factory preset temperature versions, commonly including 50°C and 60°C models. The right version depends on the way the hot water system is being installed and how temperature control is handled throughout the property.
50°C Preset Systems
Commonly used where the appliance itself is intended to limit the delivered hot water temperature for relevant sanitary outlets, subject to the installation design and applicable requirements.
60°C Systems
Can suit installations where hotter water is required elsewhere and the plumbing installation provides the required temperature control to relevant sanitary fixtures.
Powered vs Hydropower Instant Gas Hot Water
Many modern continuous flow gas systems require electricity for ignition, electronic controls and other functions. Selected hydropower or powerless models generate the energy needed for ignition from water flow instead.
| Comparison | Powered Continuous Flow | Hydropower / Powerless |
|---|---|---|
| Power Point | Commonly required | Not required on selected models |
| Electronic Controls | Greater electronic functionality available | Generally simpler |
| Controller Options | Available on many compatible systems | More limited |
| Best For | Modern family systems and advanced control options | Suitable compact replacements without nearby mains power |
Why Gas Supply Matters for Continuous Flow Hot Water
Larger instant gas water heaters can require a substantial amount of gas while operating at full output. Selecting a high-flow system does not automatically mean the property's existing gas pipework can supply it correctly.
The gas installation needs to be considered together with other gas appliances on the property. Pipe size, pipe length, available pressure, regulator arrangements and total connected gas demand can all affect the installation.
Water Pressure & Flow for Instant Gas Hot Water
Continuous flow systems need sufficient water flow and pressure to operate correctly. The appliance may be capable of a high maximum flow rate, but the home also needs enough incoming water supply and suitable pipework to make use of that capacity.
Shower heads, mixers, pressure-limiting equipment and the simultaneous operation of other fixtures can all affect the actual flow experienced at the outlet.
6-Star vs 7-Star Instant Gas Hot Water
Standard modern continuous flow systems can provide strong gas efficiency, while premium condensing systems can recover additional heat from the combustion process to achieve higher efficiency.
| Comparison | Standard Continuous Flow | Premium Condensing Continuous Flow |
|---|---|---|
| Efficiency Position | Strong modern gas efficiency | Higher-efficiency premium category |
| Heat Recovery | Conventional heat exchanger design | Recovers additional heat from combustion gases |
| Condensate | Generally not the same requirement | Condensate management forms part of installation |
| Upfront Cost | Generally lower | Generally higher |
| Best For | Value and straightforward replacement | Homeowners wanting premium gas efficiency |
How Much Does an Instant Gas Hot Water System Cost?
Calculated from currently available products in this collection using each product's lowest available advertised starting price. Your final supplied-and-installed price depends on the appliance, installation pathway, gas supply and site requirements.
Instant gas hot water system cost depends on the flow rate, brand, gas type, efficiency level, power requirements and the work required at the property. A like-for-like replacement can be significantly simpler than converting from storage or relocating the appliance.
JR Gas & Water displays current continuous flow systems and installed prices in the live product range above so customers can compare actual available options rather than relying on a broad estimated price range.
What Can Change the Installation Price?
- Continuous flow size and model.
- Natural gas or LPG configuration.
- Existing gas pipe size and available gas supply.
- Like-for-like replacement versus conversion.
- Powered versus hydropower appliance.
- Availability of a suitable electrical supply where required.
- 50°C or 60°C installation requirements.
- Existing hot and cold water pipework.
- Appliance relocation.
- Wall position and mounting requirements.
- Condensate drainage on condensing models.
- Access and removal requirements for the old system.
Instant Gas Replacement Cost: What Are You Paying For?
The product price is only the starting point. The final replacement price depends on whether the job is a straightforward like-for-like swap or needs gas pipe upgrades, electrical supply, relocation, new water pipework, temperature-control changes, condensate drainage or other site work.
Like-for-Like Replacement
Usually the simplest cost pathway where the existing gas type, pipe capacity, water connections, position and power arrangement remain suitable for the new unit.
Upsizing the Flow Rate
Moving to a larger 20L, 26L or 32L system can increase appliance cost and may require the existing gas supply to be checked or upgraded for the higher input.
Powered or Hydropower Change
Changing from a powerless unit to an electronically controlled model can introduce an electrical requirement that was not part of the old installation.
Relocation or Conversion
Moving the appliance or changing from gas storage can add gas, water, electrical, mounting and compliance work compared with a direct wall replacement.
Advertised Instant Gas Price vs Supplied-and-Installed Price
The advertised starting price lets you compare systems by brand, size and features. The installed total also needs to account for the selected installation package and the property's existing services. Use the selector and installation options already on this page for the actual pathway rather than relying on a generic one-price-fits-all estimate.
What Is Usually the Lowest-Cost Instant Gas Replacement?
A correctly sized like-for-like replacement is usually the lowest-complexity option when the existing gas type, gas pipe, water services, appliance position and power arrangement remain suitable. The cheapest appliance is not always the cheapest installed result if it needs additional gas or electrical work.
Does Natural Gas or LPG Change the Price?
The appliance must match the property's fuel type, and available models or pricing can differ between natural gas and LPG versions. The existing gas installation also matters: pipe sizing, regulators, cylinders and total connected gas demand can change the work required.
Best Instant Gas Hot Water Systems – JR Installer Picks
There is no single best continuous flow gas water heater for every home. The ideal system depends on simultaneous demand, available gas supply, natural gas or LPG, electrical availability, efficiency priorities and budget.
Best All-Round Family Pick
Rinnai Infinity B26
A strong all-round 26L class choice for family homes wanting proven Rinnai continuous flow technology, compact wall-mounted installation and enough capacity for higher household demand.
View Rinnai hot water systems →Premium High-Capacity Pick
Rinnai Infinity Enviro 32
A premium condensing option for larger homes wanting high flow, stronger gas efficiency and a larger continuous-flow capacity.
Compare 32L instant gas systems →Best Powerless Pick
Bosch Hydropower
A strong direction for compact homes and suitable replacements where the ability to operate without a standard power point is particularly valuable.
Compare hydropower systems →Instant Gas Hot Water Brands We Install
JR Gas & Water supplies continuous flow gas hot water systems across compact, mainstream and premium categories from established hot water manufacturers.
Rinnai
One of the strongest continuous-flow specialists with systems spanning compact B Series units through to larger Infinity and premium Enviro models.
View Rinnai systems →Rheem
Established Australian hot water brand offering compact and family-size continuous flow gas alternatives.
View Rheem systems →Bosch
Particularly strong in hydropowered continuous flow, including compact models designed for suitable installations without mains electrical ignition.
View Bosch systems →Thermann
Practical continuous flow systems across common family sizes with strong value and recognised Australian-market support.
View Thermann systems →Instant Gas Hot Water Installation Brisbane & Gold Coast
JR Gas & Water provides licensed continuous flow gas hot water installation and replacement throughout Brisbane and the Gold Coast. A good instant gas installation requires the appliance, gas supply, water supply, electrical requirements and building position to work together.
Gas Supply
Gas type, pipe sizing and available gas capacity need to support the selected continuous flow water heater together with the property's other gas appliances.
Water Flow & Pressure
Suitable water flow and pressure are required to make use of the appliance's continuous-flow capacity.
Electrical Supply
Many electronically controlled continuous flow systems require a suitable power supply, while selected hydropower models operate without a normal power point.
Location & Clearances
Appliance position, openings, boundaries, building features, clearances and manufacturer requirements all need to be considered.
Instant Gas vs Gas Storage Hot Water
Instant gas heats water as it is used, while gas storage heats and stores a reserve of hot water in a cylinder. Both can provide excellent family hot water when correctly selected.
| Comparison | Instant Gas | Gas Storage |
|---|---|---|
| Hot Water Storage | No storage tank | Stored in a cylinder |
| System Size | Compact wall-mounted appliance | Requires floor space for the cylinder |
| Performance Limit | Maximum simultaneous flow | Stored volume plus burner recovery |
| Heating | Only while hot water is flowing | Maintains stored hot water |
| Hot Water Duration | Continuous while demand remains within capacity | Dependent on storage plus recovery |
| Best For | Compact on-demand hot water | Homes wanting stored reserve and strong recovery |
Instant Gas vs Electric Storage Hot Water
| Comparison | Instant Gas | Electric Storage |
|---|---|---|
| Energy Source | Natural gas or LPG | Electricity |
| Storage Tank | No | Yes |
| Hot Water Limit | Flow capacity | Stored volume and recovery |
| Installation Space | Compact wall-mounted system | Requires storage-cylinder space |
| Fuel Infrastructure | Suitable gas supply required | Suitable electrical supply required |
| Best Replacement | Often simplest where continuous flow gas already exists | Often simplest where electric storage already exists |
Instant Gas Hot Water Brisbane & Gold Coast
Instant Gas Hot Water Brisbane
JR Gas & Water supplies and installs continuous flow gas hot water systems throughout Greater Brisbane, including Brisbane City, Brisbane North, Brisbane South, Logan, Ipswich, Redlands and surrounding service areas.
Brisbane homes range from older hydropower gas installations through to larger electronically controlled family systems. When replacing an existing unit, we compare the old flow rate, actual simultaneous demand and gas supply before deciding whether the replacement should remain the same size or move into another category.
View hot water installation in Brisbane →Instant Gas Hot Water Gold Coast
JR Gas & Water installs instant gas hot water systems throughout the Gold Coast for homes using suitable natural gas or LPG supplies.
Correct sizing is particularly important when customers move from a smaller older continuous-flow unit into a larger family system. Available gas supply, water flow, installation position and simultaneous bathroom demand all need to be considered together.
View hot water installation on the Gold Coast →How an Instant Gas Hot Water Replacement Works
1. Choose the Flow Rate
Size the unit around simultaneous hot water demand and the property's existing services.
2. Confirm Gas Type & Supply
Confirm natural gas or LPG and check whether the existing gas installation suits the new appliance.
3. Disconnect the Existing Unit
Gas and water services are safely isolated and the old appliance is disconnected.
4. Install the New System
The replacement is mounted and connected to suitable water, gas and electrical services where required.
5. Test the Installation
Gas work, water connections and appliance operation are checked before commissioning.
6. Commission the System
Flow, temperature and general operation are confirmed before the job is completed.
What We Have Learned Installing Instant Gas Hot Water Systems
Continuous flow systems are easy to compare badly because the headline litre rating looks simple. In practice, gas supply, simultaneous demand, temperature rise and the existing plumbing can matter just as much as the number printed on the front of the unit.
Size for Simultaneous Use
The important question is not how many people live in the house, but how many hot water outlets may operate together.
Do Not Ignore Temperature Rise
A litre-per-minute rating is based on defined conditions. Colder incoming water requires more energy per litre to reach the same outlet temperature.
Check the Gas Pipe Before Upsizing
Larger continuous flow systems can place much greater demand on the gas supply than smaller older units.
More Litres Is Not Always Better
Oversizing can add cost and gas-supply requirements without improving the household experience if the extra flow is never needed.
Powerless Systems Still Have a Place
Hydropower units remain extremely practical where an older powerless continuous-flow system is being replaced and the household demand is modest.
Controllers Can Be Worthwhile
Compatible temperature controllers can improve convenience and give households more direct control over delivered water temperature where the installation supports them.
Instant Gas Hot Water System FAQs
What is an instant gas hot water system?
An instant gas hot water system, also called a continuous flow gas water heater, heats water as it passes through the appliance rather than storing hot water in a cylinder. The burner operates when hot water is required and stops when the hot water flow ends.
Is continuous flow the same as instant gas hot water?
Yes. In residential hot water, the terms instant gas, instantaneous gas and continuous flow gas are commonly used to describe systems that heat water on demand without a storage tank.
What is the current instant gas hot water price range?
Current available systems in this collection have advertised starting prices from to . Your exact supplied-and-installed price depends on the model, gas supply and site requirements shown through the live installation options above.
Why can the installed price be higher than the advertised instant gas price?
Gas pipe upgrades, electrical supply, relocation, water pipework, mounting, temperature-control requirements, condensate drainage on condensing models and other site work can change the final total. A from price is the starting point for the relevant product or installation pathway.
Can I compare instant gas prices without requesting a quote?
Yes. JR publishes products and installation options online so you can compare sizes, brands and starting prices before booking. A written or onsite quote remains available where the job falls outside the standard online pathways.
What size instant gas hot water system do I need?
Size should be based mainly on simultaneous hot water demand. Small one-bathroom applications may suit 10L–16L systems, while 20L, 26L and 32L categories provide progressively more flow for homes with greater simultaneous demand. Gas supply, incoming water temperature and outlet flow also need to be considered.
Is a 20L instant gas hot water system enough for two bathrooms?
A 20L system can suit many moderate-demand homes, but bathroom count alone is not enough to guarantee performance. Whether two showers will operate at the same time, shower flow rates, incoming water temperature and required temperature rise all affect the result.
Is a 26L instant gas system good for a family?
A 26L class continuous flow system is one of the most common higher-capacity family categories and can suit many homes with multiple bathrooms. The actual suitability depends on simultaneous hot water demand, available gas supply and local water conditions.
What does 26 litres per minute mean?
It describes the appliance's flow capacity under specified rating conditions rather than the amount of water stored inside the unit. Continuous flow systems have no large hot water storage tank.
Does instant gas hot water ever run out?
There is no stored tank to empty, so a correctly operating continuous flow system can keep heating water for as long as the hot tap remains open. However, the system still has a maximum flow capacity, so too many simultaneous outlets can exceed what the appliance can heat effectively.
Does an instant gas hot water system need electricity?
Many modern electronic continuous flow systems require electricity for ignition and controls. Selected hydropower or powerless models can operate without a normal mains power point. The exact requirement depends on the model.
Can instant gas hot water run on LPG?
Yes, many continuous flow ranges offer LPG-compatible models. Natural-gas and LPG appliances are not automatically interchangeable, so the exact gas type needs to be confirmed before choosing the system.
What is the difference between 50°C and 60°C instant gas?
The figures refer to the appliance's temperature configuration. Different installations may use different preset versions depending on how temperature control is handled throughout the property. The correct version should be selected to suit the plumbing design and applicable outlet-temperature requirements.
Is instant gas cheaper to run than gas storage?
Continuous flow avoids maintaining a tank of stored hot water and only burns gas when hot water is being produced. Actual running cost compared with gas storage depends on appliance efficiency, gas tariff, household use and the systems being compared.
Is instant gas better than gas storage?
Neither is automatically better. Instant gas provides compact continuous hot water without a tank, while gas storage provides a stored reserve plus burner recovery. Existing services, gas supply, household demand and available installation space determine which is the better option.
Do I need a larger gas pipe for instant gas hot water?
Sometimes. Larger continuous flow appliances can require substantial gas input. The existing gas pipe size, length, available pressure and other connected gas appliances should be checked rather than assuming the current gas line is suitable.
Do you install instant gas hot water in Brisbane and Gold Coast?
Yes. JR Gas & Water supplies and installs instant and continuous flow gas hot water systems throughout Greater Brisbane, the Gold Coast, Logan, Ipswich, Redlands, Moreton Bay and surrounding South East Queensland service areas.
Compare Instant Gas Hot Water Systems
Compare continuous flow gas hot water by size, ignition type, brand or alternative hot water technology before choosing the best system for your home.
Choose Your Instant Gas Hot Water System
Compare continuous flow gas hot water systems, flow rates, brands and current installed pricing above. If you are unsure about sizing, natural gas or LPG compatibility, gas supply, water pressure, appliance location or whether continuous flow is the best option for your property, book an onsite quote assessment before choosing your replacement.
Current available instant gas systems in this collection have advertised starting prices from to . Use the live options above to confirm the installed price for your selected system and property.
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