10–13L Instant Gas Hot Water Systems From $1,549
You’re already looking at compact instant gas systems in the 10–13L/min range. We’ll show the three best suited options immediately, then refine them by flow preference, efficiency, price and brand.
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Find Your Best Compact Instant Gas System
The general capacity range is already decided. Now we’ll determine which 10L, 12L or 13L system is the best fit.
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10L, 12L & 13L Instant Gas Hot Water Systems
10L, 12L and 13L instant gas hot water systems are compact continuous-flow water heaters designed primarily for one-bathroom homes, units, apartments, granny flats and households with relatively low simultaneous hot water demand.
They are also known as continuous flow gas hot water systems, instantaneous gas water heaters, tankless gas hot water systems and on-demand gas water heaters. All describe the same basic principle: water is heated as it passes through the appliance rather than being stored in a hot water cylinder.
JR Gas & Water supplies, replaces and installs compact 10L–13L gas continuous-flow systems throughout Greater Brisbane, the Gold Coast, Logan, Ipswich, Redlands, Moreton Bay and surrounding South East Queensland areas.
Current options include conventional electronically controlled continuous-flow systems as well as hydropowered or powerless units that do not require a standard electrical connection for ignition.
Instant Gas, Continuous Flow, Tankless & Instantaneous Hot Water
Different brands and customers use different terminology for compact gas water heaters. These terms generally describe the same category.
| Term | Meaning |
|---|---|
| Instant Gas Hot Water | Water is heated when a hot tap creates demand. |
| Continuous Flow Gas Hot Water | The common Australian industry term for gas water heaters without a storage tank. |
| Instantaneous Gas Water Heater | Another term for heating the water immediately as it flows through the appliance. |
| Tankless Gas Hot Water | Common international wording describing the lack of a stored hot water cylinder. |
| On-Demand Gas Hot Water | Describes the appliance firing when hot water is requested rather than maintaining stored hot water. |
Who Are 10L–13L Continuous Flow Gas Systems Best For?
One-Bathroom Homes
The core application for this capacity range is a home where one shower represents the main peak hot water demand.
Units & Apartments
Compact wall-mounted design can suit smaller properties where a storage cylinder would use unnecessary space.
Granny Flats
Useful where the dwelling has one bathroom and relatively modest simultaneous hot water demand.
One or Two Occupants
Household size can be low even when hot water comfort still matters. Correctly sized continuous flow provides long shower duration without a storage tank running empty.
Older Mechanical Replacements
Hydropowered models can be particularly useful when replacing older instantaneous gas units that did not require a nearby powerpoint.
Low Simultaneous Demand
Best suited where several high-flow fixtures are not expected to draw hot water at the same time.
10L vs 12L vs 13L Instant Gas Hot Water
The numerical difference looks small, but at this end of the range every additional litre per minute increases the amount of hot water available while the system is operating.
| Flow Class | General JR Position | Best Application |
|---|---|---|
| 10L/min | Lowest compact flow | Small homes, one shower and light simultaneous demand |
| 12L/min | Balanced compact size | One-bathroom homes wanting slightly stronger flow and broader product choice |
| 13L/min | Highest flow in this compact collection | One-bathroom homes wanting maximum flow before moving into the 16L category |
Best 10L, 12L & 13L Instant Gas Systems – JR Installer Picks
This category includes two different buying directions: conventional powered continuous-flow systems with more electronic control, and hydropowered or powerless systems that can operate without a normal electrical connection.
Best Overall Compact Pick
Bosch HydroPower 13H
A strong all-round compact option where the homeowner wants the highest flow in this collection together with Bosch HydroPower ignition and no normal power-point requirement.
View Bosch HydroPower 13H →Best Modern 12L Pick
Rinnai Infinity B12
A modern one-bathroom continuous-flow system with precise temperature control, compact dimensions and strong efficiency from one of the largest names in Australian continuous-flow gas.
View Rinnai Infinity B12 →Best Powerless 12L Pick
Rheem Pronto 12
A strong replacement direction where the property suits hydro-electric ignition and the homeowner wants a recognised brand without needing a normal electrical connection for the heater.
View Rheem Pronto 12 →Best Compact 10L HydroPower Pick
Bosch HydroPower 10H
A logical option for genuinely low-demand one-bathroom properties, delivering a 10L/min class flow rate without a normal electrical connection.
View Bosch HydroPower 10H →Compact Powerless Alternative
Rinnai Flowmaster 10
A compact gas-only continuous-flow direction for lighter-demand homes, particularly where avoiding a power-point requirement is useful.
View Rinnai Flowmaster 10 →Rheem Electronic 12L Option
Rheem 12 Continuous Flow
A compact Japanese-made Rheem continuous-flow option for one-bathroom homes wanting electronic control and a modern 12L-class gas water heater.
View Rheem 12 Continuous Flow →Are 10L–13L Gas Systems Big Enough for One Bathroom?
Yes — this is primarily the one-bathroom continuous-flow category.
Rinnai currently describes its Infinity B12 specifically as ideal for one-bathroom homes. Bosch also positions its 10H and 13H HydroPower systems as compact continuous-flow products, with 10L/min and 13L/min output respectively at a 25°C temperature rise.
The important distinction is between one bathroom existing and one shower being the main simultaneous demand.
Good Match
- One normal shower operating at a time.
- Small household.
- Kitchen or basin use mainly occurs separately.
- Low to moderate fixture flow rates.
- Existing small continuous-flow unit has historically been adequate.
Consider Moving Larger
- Two showers regularly operate together.
- High-flow shower fixtures are used.
- Strong kitchen or laundry demand occurs while showering.
- The household already complains about inadequate flow.
- A future second bathroom is planned.
What Does 10L, 12L or 13L per Minute Mean?
The litre figure on a continuous-flow gas system is a flow rating, not a tank capacity.
A Bosch 10H, for example, is specified at 10 litres per minute at a 25°C temperature rise. Bosch 13H is specified at 13 litres per minute at the same temperature-rise condition. The Rinnai B12 is a 12L/min class unit under comparable rating conditions.
If the incoming water is colder or the required outlet water is hotter, the appliance has to add more heat to each litre. Available flow therefore changes with temperature rise.
10L/min Does Not Mean a 10L Tank
There is no storage cylinder. The system heats water continuously as it passes through the appliance.
Flow Is Shared
If several hot outlets operate together, they share the available heated-water capacity.
Temperature Rise Matters
Colder incoming water requires more burner output per litre than warmer incoming water.
Size Small Continuous Flow Gas by Demand, Not Occupant Count
Occupant count is much less useful for continuous-flow gas than it is for storage hot water.
A one-person household and a four-person household may both use the same 12L system successfully if only one shower operates at a time. The four people simply use the system for longer across the day.
What matters more is the amount of hot water required at the same moment.
| Household Situation | What Matters |
|---|---|
| One person, one shower | Low simultaneous demand — compact system often appropriate |
| Four people showering one after another | Duration is long but simultaneous demand remains low |
| Two people showering at the same time | Simultaneous flow increases significantly — larger system normally preferable |
| Shower plus high-flow kitchen use | Available flow is shared between outlets |
Powerless & Hydropowered 10L–13L Gas Hot Water
One of the most useful features in the compact instant-gas category is the availability of systems that do not require a conventional powerpoint for ignition.
Bosch HydroPower systems use water flow through a small internal turbine to create the energy required for ignition. Rheem Pronto uses an inbuilt hydro-electric generator for the same basic purpose.
| System | Flow Class | Normal Powerpoint Required? |
|---|---|---|
| Bosch HydroPower 10H | 10L/min | No |
| Rinnai Flowmaster 10 | 10L/min class | No |
| Rheem Pronto 12 | 12L/min | No |
| Bosch HydroPower 13H | 13L/min | No |
| Rinnai Infinity B12 | 12L/min | Powered electronic continuous-flow system |
Powered vs Powerless Compact Continuous Flow Gas
| Comparison | Powered Electronic Unit | Hydropower / Powerless Unit |
|---|---|---|
| Electrical Connection | Requires suitable electrical supply | No conventional power outlet required on applicable models |
| Controls | Often more advanced electronic temperature management | Generally simpler control architecture |
| Replacement Advantage | Good where power already exists | Very useful where replacing older mechanical gas heaters |
| Flow Capacity | Depends on selected model | Depends on selected model |
| Efficiency | Depends on exact appliance | Depends on exact appliance |
| Best Choice | Modern installations prioritising electronic control | Simple one-bathroom replacements without convenient power |
13L vs 16L Continuous Flow Gas Hot Water
The move from 13L to 16L is the first logical step when the compact range starts to feel marginal.
| Comparison | 10L–13L | 16L |
|---|---|---|
| Category | Compact continuous flow | Stronger one-bathroom continuous flow |
| Main Use | Lower simultaneous demand | One bathroom with greater flow requirement |
| Available Flow | 10–13L/min class | 16L/min class |
| Physical Size | Compact | Still compact wall-mounted format |
| Best Reason to Upsize | — | Higher fixture flow or more overlapping hot water use |
Do Small Continuous Flow Systems Still Need Gas Supply Checks?
Yes. A compact continuous-flow appliance still needs enough gas supplied at the correct pressure to produce its rated output.
Smaller 10L–13L systems generally have lower maximum gas demand than large 26L or 32L models, which is one reason they can suit older homes and compact replacement applications. But existing pipework should never be assumed suitable solely because the new appliance is physically small.
Natural Gas & LPG 10L–13L Continuous Flow Systems
Several systems in this compact category are available in fuel-specific Natural Gas and LPG versions.
The correct version must match the property's gas supply. A Natural Gas appliance and an LPG appliance should not be treated as interchangeable simply because the product name and flow rating are the same.
Natural Gas
Common where the property already has a reticulated Natural Gas supply and an existing gas hot water installation.
LPG
Useful for properties supplied by LPG, with cylinder capacity and overall gas demand considered as part of the installation.
50°C vs 60°C Small Continuous Flow Gas Systems
Selected compact continuous-flow products are available in different outlet-temperature configurations.
For example, JR's current Rheem 12 page identifies the model as a 50°C preset continuous-flow system. Rinnai B12 is available in configurations designed around 50°C or 60°C applications.
The correct configuration depends on the plumbing design, fixtures supplied and required temperature-control arrangement.
Small Continuous Flow Gas vs Gas Storage
| Comparison | 10L–13L Continuous Flow | Gas Storage |
|---|---|---|
| Storage Tank | No | Yes |
| Hot Water Duration | Continuous while demand stays within flow capacity | Limited by stored water plus recovery |
| Sizing Method | Simultaneous flow | Stored volume + recovery |
| Footprint | Compact wall-mounted appliance | Larger ground-mounted cylinder |
| Main Small-Home Advantage | No need to store a large quantity of hot water for low demand | Stored reserve can support short high-flow bursts |
Replacing an Older 10L, 12L or 13L Gas Water Heater
Small continuous-flow systems are common replacements for older instantaneous gas water heaters because they retain the same general tankless format without unnecessarily increasing flow.
A replacement still needs to be matched to the existing installation.
JR Checks:
- Existing appliance flow rate.
- Whether the old unit actually kept up with demand.
- Natural Gas or LPG.
- Gas pipe size and available capacity.
- Hot and cold water connection positions.
- Existing mounting position.
- Required clearances.
- Whether the new system needs electricity.
- 50°C or 60°C requirements.
- Whether increasing to 16L would provide a better result.
How Much Does a 10L–13L Instant Gas Hot Water System Cost?
Compact continuous-flow systems sit at the smaller end of the gas instantaneous market, but installed cost still depends on the specific product and property.
JR displays current live supply-and-install pricing in the product grid above rather than hardcoding a price into this lower-page content.
What Can Change the Installed Price?
- 10L, 12L or 13L model selected.
- Natural Gas or LPG.
- Powered versus hydropowered system.
- Existing gas pipework.
- Existing water connections.
- Need for a new powerpoint on powered models.
- 50°C or 60°C installation requirements.
- Like-for-like replacement versus relocation.
- Changing from gas storage or electric hot water.
- Access and mounting conditions.
10L–13L Continuous Flow Gas Installation Brisbane & Gold Coast
JR Gas & Water supplies and installs small continuous-flow gas hot water systems throughout Brisbane and the Gold Coast.
1. Confirm Demand
Check that the household genuinely suits the compact 10L–13L flow range.
2. Select Power Type
Compare electronic continuous flow with hydropower or powerless alternatives where appropriate.
3. Check Gas Supply
Confirm gas type, pipe capacity and appliance requirements.
4. Check Connections
Assess water pipework, electrical requirements, mounting and clearances.
5. Install the System
Complete the gas, water, electrical and mounting work required for the chosen installation package.
6. Test & Commission
Test appliance operation, flow, outlet temperature and gas performance before completion.
Small Continuous Flow Gas Hot Water Brisbane & Gold Coast
10L–13L Instant Gas Brisbane
JR Gas & Water supplies and installs compact 10L, 12L and 13L continuous-flow gas hot water systems throughout Greater Brisbane, including Brisbane City, Brisbane North, Brisbane South, Logan, Ipswich, Redlands and surrounding service areas.
These systems are particularly useful for smaller one-bathroom homes, units, granny flats and like-for-like replacements where the existing compact gas heater has historically met the household's demand.
View Brisbane Hot Water Installation →10L–13L Instant Gas Gold Coast
JR Gas & Water installs compact instant and continuous-flow gas systems throughout the Gold Coast for homes needing efficient on-demand hot water without an unnecessarily large flow rate.
We compare actual shower demand, gas supply, fuel type and whether a powered or hydropowered system best suits the existing installation.
View Gold Coast Hot Water Installation →What We Have Learned Installing Small Continuous Flow Gas Systems
One Shower Is the Key Use Case
These systems work best where one shower represents the major simultaneous hot water demand.
Occupant Count Can Be Misleading
Four people showering one after another can suit a compact continuous flow system better than two people trying to run two showers together.
13L Does Not Replace a 20L System
A few extra litres per minute improve performance, but the compact category remains fundamentally different from larger whole-home flow classes.
Powerless Units Still Make Sense
Hydro-electric ignition remains extremely practical for older one-bathroom gas installations without convenient electrical supply.
Do Not Upsize Without a Reason
If the old 12L unit was always adequate, replacing it with another well-selected 12L can be a better decision than paying for unused 26L capacity.
Check Fixture Flow
Modern low-flow showers are much easier for a compact continuous-flow system to support than older high-flow shower fixtures.
10L, 12L & 13L Instant Gas Hot Water FAQs
Is 10L instant gas hot water enough for a house?
It can be suitable for a small one-bathroom home with low simultaneous demand. If multiple hot outlets regularly operate together, a larger continuous-flow system is usually preferable.
Is a 12L continuous flow gas system enough for one bathroom?
Yes. The 12L class is primarily a one-bathroom category. Rinnai specifically positions its Infinity B12 for one-bathroom homes. Actual fixture flow and simultaneous use still matter.
Is 13L instant gas enough for one bathroom?
Yes. A 13L system is a strong compact one-bathroom option and provides the highest nominal flow within JR's current 10L–13L collection.
Is 13L instant gas enough for two bathrooms?
Having two bathrooms is possible, but regularly running two showers together can exceed what a 13L-class unit is intended to provide. For genuine simultaneous two-shower demand, compare larger continuous-flow systems.
What is the difference between 10L, 12L and 13L instant gas?
The main difference is available heated-water flow. A 13L-class unit can provide more flow under comparable temperature-rise conditions than a 10L system. All remain at the compact end of the residential continuous-flow market.
Does a 13L gas system store 13 litres of hot water?
No. The 13L figure describes continuous-flow output under specified test conditions. There is no 13-litre storage tank inside the appliance.
Can a small continuous-flow gas system run out of hot water?
It does not run empty like a storage cylinder. It can continue heating while water flows, provided the required instantaneous flow remains within the unit's heating capacity.
Can four people use a 12L instant gas hot water system?
Potentially, because occupant count does not determine continuous flow capacity. Four people showering one after another create much less instantaneous demand than two people showering at the same time.
What is the best 10L instant gas hot water system?
Bosch HydroPower 10H is a strong compact option where a homeowner wants a 10L/min-class continuous-flow system without a conventional electrical connection. Rinnai Flowmaster 10 provides another compact powerless direction.
What is the best 12L instant gas hot water system?
Rinnai Infinity B12 is our stronger modern electronic direction, while Rheem Pronto 12 is particularly useful when a homeowner wants hydro-electric ignition without a normal power-point requirement.
What is the best 13L instant gas hot water system?
Bosch HydroPower 13H is JR's current compact 13L option and is a strong all-round choice for a one-bathroom home wanting hydropower ignition and no conventional electrical connection.
Does Bosch HydroPower 10 need electricity?
No conventional electrical connection is required. Bosch HydroPower uses water flow through an internal turbine to provide energy for ignition.
Does Bosch HydroPower 13 need electricity?
No conventional electrical connection is required. The HydroPower system generates ignition energy from water flow.
Does Rheem Pronto 12 need a powerpoint?
No. Rheem Pronto 12 uses an inbuilt hydro-electric generator for ignition and does not require a normal electrical connection.
Does Rinnai Infinity B12 need electricity?
Yes. The Infinity B12 is an electronically controlled continuous-flow gas water heater and requires the electrical arrangement specified by Rinnai for installation.
Is continuous flow gas the same as instant gas hot water?
Yes. Instant gas, continuous-flow gas, instantaneous gas, tankless gas and on-demand gas are commonly used to describe the same general hot water technology.
Should I choose 13L or 16L instant gas?
Choose 13L where household demand is comfortably within the compact one-bathroom category. Move to 16L where shower flow or overlapping fixture use makes the smaller range marginal.
Can 10L–13L gas systems run on LPG?
Applicable products are available in fuel-specific LPG and Natural Gas versions. The correct version must be selected for the property's gas supply.
Can a 12L gas system replace an older instantaneous heater?
Often yes, particularly where the old system had similar flow and the household was satisfied with its performance. Gas supply, connection positions, electrical requirements and compliance still need to be checked.
How much does a 10L–13L continuous flow gas system cost installed?
Installed cost depends on the model, fuel type, existing system, gas supply, power requirements, pipework and whether the job is a like-for-like replacement or conversion. JR displays current live installed prices in the product grid above.
Do you install 10L, 12L and 13L instant gas in Brisbane and Gold Coast?
Yes. JR Gas & Water supplies and installs compact 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 & Continuous Flow Gas Hot Water by Size
If 10L–13L is too small for your expected simultaneous hot water demand, compare the next continuous-flow sizes rather than oversizing or undersizing blindly.
Choose Your 10L, 12L or 13L Continuous Flow Gas System
Compare compact instant gas systems, 10L–13L flow rates, hydropower and electronic ignition, Natural Gas and LPG options and current installed pricing above. If you are unsure whether the compact range provides enough simultaneous flow or whether your home should move to 16L or larger, book an onsite quote assessment before choosing your replacement.