Best Rinnai Hot Water Systems: Complete Buyer’s Guide

Rinnai is one of the most commonly compared hot water brands in Australia, especially for gas and instant gas hot water systems. The best Rinnai hot water system depends on your household size, number of bathrooms, gas type, water pressure, current hot water setup, available space and whether you are replacing like-for-like or changing system type.

At Hot Water Outlet, you can compare Rinnai hot water systems, hot water systems, gas hot water systems, instant gas hot water systems, electric hot water systems, heat pump hot water systems and common valves, pipework and fittings.

Quick Answer: Which Rinnai Hot Water System Is Best?

The best Rinnai hot water system is the one that matches your household’s gas type, flow demand, bathroom count, water pressure and replacement requirements.

As a general guide:

• Choose a Rinnai instant gas system if you want continuous flow hot water and your home has suitable natural gas or LPG supply.

• Choose a higher-flow Rinnai model if you have a larger household, two bathrooms or higher peak hot water demand.

• Choose a lower-flow Rinnai model if you have a smaller home, one bathroom or lower hot water demand.

• Confirm whether you need natural gas or LPG before ordering.

• Compare flow rate in L/min for instant gas systems.

• Check gas supply, water pressure, external wall location and controller compatibility.

• Compare electric, heat pump or storage alternatives if gas is not available or not practical.

For many buyers, Rinnai is most relevant when comparing instant gas hot water systems, but the right choice still depends on the home.

Rinnai Hot Water Systems at a Glance

Rinnai is often compared for gas and continuous flow hot water, but the best system still depends on whether the property can support the selected model.

Start With Your Current Hot Water System

Before choosing a Rinnai hot water system, check your current setup.

Look for:

• Current brand and model

• System type

• Flow rate in L/min if instant gas

• Tank capacity if storage

• Natural gas or LPG if gas

• Existing location

• External wall access

• Water pressure and flow

• Gas meter or LPG bottle setup

• Connection positions

• Whether the current system keeps up

• Whether household demand has changed

If the current Rinnai system has worked well, a similar replacement may be practical.

If the current system struggles, runs cold, cannot handle overlapping showers or no longer suits the home, compare different Rinnai sizes or other system types before ordering.

Rinnai Instant Gas Hot Water Systems

Rinnai instant gas hot water systems heat water as it passes through the unit. They do not store a large tank of hot water.

Instant gas systems are sized by flow rate in L/min.

A Rinnai instant gas system may suit:

• Homes with natural gas or LPG

• Properties wanting continuous flow hot water

• Homes replacing an old instant gas unit

• Households that do not want a large storage tank

• Families with suitable gas supply and water pressure

• Two-bathroom homes where the selected flow rate is suitable

• Buyers wanting to compare compact external gas hot water options

Before choosing a Rinnai instant gas system, check:

• Flow rate in L/min

• Natural gas or LPG

• Number of people in the home

• Number of bathrooms

• Whether showers may run close together

• Bath use

• Gas supply suitability

• Water pressure and flow

• External wall location

• Controller compatibility

• Product dimensions

• Required valves and fittings

A Rinnai instant gas system can be a strong option where the gas supply, water pressure and model size all suit the property.

Rinnai Gas Hot Water Systems

Rinnai gas hot water systems may suit homes already using gas or properties where gas hot water is preferred.

Gas hot water may suit:

• Natural gas homes

• LPG properties

• Families with higher hot water demand

• Homes replacing an existing gas system

• Buyers wanting continuous flow hot water

• Homes where external gas unit placement is suitable

Before choosing Rinnai gas hot water, check:

• Natural gas or LPG

• Instant gas or storage-style system type

• Flow rate in L/min if instant gas

• Gas supply suitability

• Water pressure and flow

• Number of bathrooms

• Product dimensions

• Connection requirements

• Required valves and fittings

Natural gas and LPG models are not interchangeable. Always confirm the correct gas type before ordering.

Rinnai Electric Hot Water Alternatives

Rinnai is often searched by buyers looking for gas hot water, but not every home is suited to gas.

A standard electric hot water system may be more practical if:

• Natural gas or LPG is not available

• Gas supply is not suitable

• A storage tank is already installed

• A straightforward like-for-like electric replacement is preferred

• External gas unit placement is not practical

• Upfront product cost is a key factor

Electric storage systems are sized by tank capacity in litres, not L/min.

If your home does not suit Rinnai gas hot water, compare electric storage before ordering.

Rinnai Heat Pump Alternatives

If you are comparing Rinnai because you want a more efficient hot water option, it may also be worth comparing heat pump hot water systems.

Heat pump hot water may suit if:

• You are replacing electric storage

• Outdoor space is available

• Airflow is suitable

• Noise placement is acceptable

• Condensate drainage can be managed

• Electrical requirements can be met

• Tank capacity suits household demand

Heat pump hot water may not suit homes with poor airflow, tight side access, limited outdoor space or difficult drainage.

If gas is not available and heat pump is not practical, standard electric storage may still be the better option.

Rinnai Flow Rate Explained

Rinnai instant gas systems are commonly compared by flow rate in L/min.

Flow rate helps estimate how much hot water the unit can supply at once.

A higher L/min model may suit higher demand, but only if the property can support it. Gas supply and water pressure matter.

Best Rinnai Hot Water System for One Bathroom

A one-bathroom home may suit a lower or moderate-flow Rinnai instant gas system if the household demand is suitable.

A Rinnai system may suit if:

• Natural gas or LPG is available

• The selected flow rate matches usage

• Gas supply can support the unit

• Water pressure is suitable

• External wall location is practical

• The household does not regularly run multiple hot outlets together

A one-bathroom home does not always mean low demand. A one-bathroom family home may need a stronger system than a one-bathroom home with one or two people.

Best Rinnai Hot Water System for Two Bathrooms

Two-bathroom homes need more careful sizing because showers and outlets may overlap.

A Rinnai instant gas system may suit a two-bathroom home if:

• A suitable L/min flow rate is selected

• Natural gas or LPG is confirmed

• Gas supply can support the model

• Water pressure and flow are suitable

• Two outlets may run close together

• The unit location meets clearance and access requirements

For two bathrooms, do not choose only by product price. Flow rate, gas supply and water pressure are more important.

Best Rinnai Hot Water System for Families

Families usually have higher hot water demand, especially during morning and evening peaks.

A Rinnai system for a family should be selected based on:

• Number of people in the home

• Number of bathrooms

• Shower duration

• Back-to-back showers

• Bath use

• Whether two showers may run together

• Kitchen and laundry hot water use

• Natural gas or LPG

• Gas supply capacity

• Water pressure and flow

Rinnai instant gas may suit families where the selected flow rate and property conditions line up.

If gas supply is limited or the home does not suit continuous flow, compare electric storage or heat pump alternatives before ordering.

Best Rinnai Hot Water System for Small Homes

Small homes may suit Rinnai instant gas if gas is available and the unit can be located correctly.

A Rinnai instant gas system may suit a small home if:

• Hot water demand is low to moderate

• Natural gas or LPG is available

• External wall space is suitable

• The chosen flow rate matches household use

• Gas supply and water pressure are suitable

• A storage tank is not preferred

Small homes still need correct sizing. Do not assume the smallest model is automatically right.

Best Rinnai Hot Water System for Units

Units can be more complicated because of space, building rules and body corporate requirements.

A Rinnai system may suit a unit if:

• The building already supports gas hot water

• Natural gas or LPG is confirmed

• External unit placement is allowed

• Clearances can be met

• Body corporate rules allow the replacement

• Water pressure and gas supply are suitable

• The selected model suits household demand

A Rinnai gas system may not suit every unit. If external location or building approval is difficult, electric storage or other alternatives may be more practical.

Best Rinnai Hot Water System for Townhouses

Townhouses can suit Rinnai gas hot water, but the layout needs careful checking.

Important checks include:

• Side access

• External wall space

• Gas meter or LPG bottle location

• Distance from windows and openings

• Neighbouring bedrooms

• Water pressure

• Gas supply capacity

• Body corporate or complex rules

• Delivery access

• Controller requirements

Rinnai instant gas may suit gas-connected townhouses where location, clearance and flow demand are suitable.

Best Rinnai Hot Water System for Rental Properties

Rental properties need practical hot water systems that suit likely tenant demand.

A Rinnai gas system may suit a rental if:

• Gas hot water is already installed

• Natural gas or LPG is confirmed

• The selected model suits expected usage

• Gas supply and water pressure are suitable

• The unit location is practical

• A continuous flow system is preferred

For rentals, avoid choosing too low a flow rate just to reduce product cost. If tenants run out of hot water or experience poor flow, complaints may follow.

Best Rinnai Hot Water System for Renovations

Renovations are a good time to reassess hot water because the final home may have higher demand than the old layout.

A Rinnai system may suit a renovation if:

• Natural gas or LPG is available

• A second bathroom is being added

• External wall space can be planned early

• Gas supply can be checked before ordering

• Water pressure can be assessed

• Controller locations can be planned where relevant

• The selected flow rate suits the finished home

Plan hot water around the finished property, not the old system.

Rinnai Natural Gas vs LPG

If you are choosing Rinnai gas hot water, gas type must be confirmed before ordering.

Gas models may be:

• Natural gas

• LPG

Natural gas and LPG systems are not interchangeable.

Before ordering, check:

• Existing hot water unit label

• Gas meter

• LPG bottle setup

• Product listing

• Appliance data plate

• Licensed gas fitter advice if unsure

Choosing the wrong gas type can cause delays, compatibility issues and extra costs.

Rinnai External Gas Unit Placement

Most instant gas units are installed externally unless the specific product is designed and approved for another installation type.

Before choosing a Rinnai external gas unit, check:

• External wall location

• Clearance from windows and doors

• Clearance from openings

• Distance to gas supply

• Distance to water connections

• Access for servicing

• Weather exposure requirements

• Drainage where relevant

• Controller wiring where relevant

• Compliance requirements

Do not assume an external gas unit can be installed indoors. Product type and compliance requirements matter.

Rinnai Controller Compatibility

Some Rinnai instant gas systems may be compatible with controllers, depending on the model.

Controllers may be used to help manage water temperature or convenience, but compatibility must be confirmed.

Before ordering controllers, check:

• Product compatibility

• Number of controllers supported

• Controller location

• Wiring requirements

• Existing controller setup

• Licensed trade requirements

• Whether controllers are included or separate

Do not assume old controllers will work with every new model.

Rinnai Gas Supply Requirements

Instant gas performance depends heavily on gas supply.

Before choosing a Rinnai instant gas system, check:

• Gas meter capacity

• Gas pipe sizing

• Distance from gas supply

• Other gas appliances

• Natural gas or LPG setup

• Regulator requirements where relevant

• Appliance load

• Licensed gas fitter advice

A larger L/min unit may not perform properly if the gas supply is not suitable.

Rinnai Water Pressure and Flow

Water pressure and flow also affect instant gas performance.

Before choosing Rinnai instant gas, check:

• Mains water pressure

• Existing shower flow

• Number of hot outlets

• Whether outlets run together

• Existing pipework

• Pressure limiting valves

• Product specifications

• Licensed plumber advice where needed

If the water supply is poor, upgrading the hot water unit alone may not solve the problem.

Rinnai vs Other Hot Water Brands

Rinnai is often compared with other hot water brands depending on system type.

You may want to compare:

• Rheem hot water systems for broader electric, gas, heat pump and storage options

• Bosch hot water systems for gas hot water comparisons

• Dux hot water systems for electric and gas storage-style options

• Vulcan hot water systems for practical storage-style replacements

• iStore hot water systems for heat pump comparisons

The best brand depends on system type and property suitability.

Rinnai Supply-Only Pricing vs Installed Cost

When comparing Rinnai hot water systems online, make sure you understand what the price includes.

Hot Water Outlet sells supply-only hot water systems and accessories online. Supply-only pricing usually does not include:

• Installation

• Plumbing labour

• Gas fitting

• Electrical work

• Old unit removal

• Disposal

• Valves

• Fittings

• Pipework changes

• Gas upgrades

• Controller wiring

• Compliance upgrades

• Concrete bases or platforms

• Delivery beyond what is shown at checkout

Before ordering, confirm full job requirements with licensed tradespeople.

Rinnai Valves, Fittings and Accessories

A Rinnai hot water order may need valves, fittings or accessories as well as the main unit.

Common items include:

• Tempering valves

• Pressure relief valves

• Duo valves

• Non-return valves

• Isolation valves

• Copper pipework

• Gas fittings

• Controllers where compatible

• Connection parts

Hot Water Outlet has a dedicated range of valves, pipework and fittings to help customers compare common hot water accessories.

Always confirm compatibility before ordering.

Common Mistakes When Buying a Rinnai Hot Water System

Choosing Flow Rate by Price Alone

The cheapest model may not suit families, two bathrooms or higher peak demand.

Forgetting Natural Gas vs LPG

Gas type must be correct. Natural gas and LPG models are not interchangeable.

Ignoring Gas Supply

A higher-flow instant gas system needs suitable gas supply.

Ignoring Water Pressure

Poor water pressure or flow can affect performance.

Assuming All Rinnai Units Are the Same

Different models have different flow rates, dimensions, compatibility and specifications.

Comparing L/min to Storage Tank Litres

Instant gas L/min and storage tank litres are not the same measurement.

Forgetting Controllers and Accessories

Controllers, valves and fittings may need to be ordered separately.

Assuming External Gas Units Can Go Indoors

External gas units are outdoor/external only unless the specific model is designed and approved for internal/flued installation.

Rinnai Buyer Checklist

Before choosing a Rinnai hot water system, check:

• Current hot water system type

• Current brand and model

• Current flow rate or tank capacity

• Whether the current system keeps up

• Natural gas or LPG

• Number of people in the home

• Number of bathrooms

• Shower habits

• Bath use

• Required flow rate in L/min

• Gas supply suitability

• Water pressure and flow

• External wall location

• Clearances

• Controller compatibility

• Product dimensions

• Connection positions

• Delivery access

• Required valves and fittings

• Warranty information

• Licensed trade requirements

Compare Rinnai Hot Water Systems Online

Hot Water Outlet makes it easier to compare Rinnai hot water systems by flow rate, gas type, product dimensions and specifications.

Start with:

• Rinnai Hot Water Systems

• Instant Gas Hot Water Systems

• Gas Hot Water Systems

• Hot Water Systems

• Valves, Pipework and Fittings

If Rinnai is not the best match for your home, compare other system types such as electric hot water systems and heat pump hot water systems.

FAQs About Rinnai Hot Water Systems

Are Rinnai hot water systems good?

Rinnai hot water systems are commonly compared by Australian buyers, especially for gas and instant gas hot water. The right Rinnai system depends on gas type, flow rate, water pressure, household demand and property suitability.

Which Rinnai hot water system is best?

The best Rinnai hot water system is the model that suits your home’s gas type, flow demand, bathroom count, water pressure and installation location. Smaller homes may suit lower-flow options, while families and two-bathroom homes may need higher-flow systems.

What size Rinnai instant gas system do I need?

Instant gas systems are sized by flow rate in L/min. A smaller home may suit a lower-flow model, while a larger family or two-bathroom home may need a higher-flow model, subject to gas supply and water pressure.

Is Rinnai better for gas or electric hot water?

Rinnai is commonly compared for gas and instant gas hot water. If gas is not available or not practical, compare electric or heat pump alternatives before ordering.

Is Rinnai natural gas or LPG?

Rinnai gas models may be available in natural gas or LPG versions depending on the product. Natural gas and LPG are not interchangeable, so always order the correct model.

Can I replace my old Rinnai with another Rinnai?

Yes, if a suitable replacement model is available and the flow rate, gas type, dimensions, location and connection requirements suit the home. Still check whether the old system was correctly sized.

Is Rinnai instant gas good for families?

Rinnai instant gas may suit families where the selected L/min rating, gas supply and water pressure are suitable. Family homes should avoid choosing too low a flow rate.

Is Rinnai hot water good for two bathrooms?

A Rinnai instant gas system may suit two bathrooms if the correct flow rate is selected and the property has suitable gas supply and water pressure.

Do Rinnai systems need valves and fittings?

Some Rinnai replacements require valves, fittings, controllers or accessories depending on the model and installation setup. Browse valves, pipework and fittings and confirm compatibility before ordering.

Can I install a Rinnai hot water system myself?

No. Hot water systems involve plumbing, gas and electrical work that should be completed by appropriately licensed tradespeople. Hot Water Outlet sells supply-only hot water systems and accessories online, and may help organise quotes from reputable installers where appropriate.

Find the Right Rinnai Hot Water System

The best Rinnai hot water system depends on your gas type, household demand, bathroom count, water pressure, available location and replacement requirements. Rinnai instant gas may suit homes wanting continuous flow hot water with suitable natural gas or LPG supply. Other homes may be better suited to electric storage or heat pump hot water.

Browse Rinnai hot water systems online with Hot Water Outlet to compare Rinnai hot water options by flow rate, gas type and product specifications.