Instant Electric Hot Water System Replacement Cost: Australian Buyer’s Guide

Jun 21, 2026

Replacing an instant electric hot water system can be a good option for specific applications, but it is not the same as replacing a standard electric storage tank. Instant electric systems heat water as it flows through the unit, which means they can be compact and convenient, but they can also have high electrical requirements.

For many homes, instant electric hot water is best suited to point-of-use applications, smaller fixtures, compact spaces or carefully assessed installations where the electrical supply can support the system. It should not be treated as a simple replacement for every full-size electric storage, heat pump or gas hot water system.

This guide explains what affects instant electric hot water replacement cost, when instant electric makes sense, when electric storage or heat pump hot water may be better, and what to check before ordering.

You can compare Instant Electric Systems, Electric Hot Water Systems, Heat Pump Hot Water Systems, broader Hot Water Systems, Gas Hot Water Systems and Instant Gas Hot Water Systems online with Installed Today.

Quick answer: what affects instant electric hot water replacement cost?

Instant electric hot water replacement cost depends heavily on the electrical setup and the application.

The main cost factors include:

Brand and model
Flow rate requirements
Temperature rise required
Point-of-use or whole-home application
Existing electrical supply
Switchboard capacity
Circuit requirements
Cable size
Isolation requirements
Water pressure
Installation location
Pipework changes
Access
Old unit removal
Disposal
Compliance upgrades
Whether a standard electric storage or heat pump system would suit better

The product price is only one part of the total cost. Electrical requirements can have a major impact on whether instant electric is practical.

What is an instant electric hot water system?

An instant electric hot water system heats water only when a hot tap is turned on.

Unlike electric storage hot water, it does not keep a tank of hot water heated. Water flows through the unit and is heated on demand by electric heating elements.

Instant electric systems are also called:

Tankless electric hot water systems
Continuous flow electric hot water systems
Instantaneous electric hot water systems
Point-of-use electric water heaters

They can be useful in the right setting, but they need careful electrical and flow-rate checks.

How instant electric hot water works

A simple instant electric process looks like this:

A hot tap is turned on
Water flows through the instant electric unit
The unit detects water flow
Electric elements heat the water as it passes through
Heated water travels to the outlet
The unit stops heating when water flow stops

Because the system heats water quickly as it flows, electrical demand can be high. That is why instant electric suitability should always be checked before ordering.

Instant electric vs electric storage replacement cost

Instant electric and electric storage hot water systems solve different problems.

Feature	Instant electric hot water	Electric storage hot water
Hot water style	Heated on demand	Stored in a tank
Tank required	No	Yes
Space required	Compact	Needs tank space
Electrical demand	Can be high	Depends on tank and element
Best use	Point-of-use or suitable low-demand applications	Whole-home hot water
Replacement pathway	Electrical checks are critical	Common like-for-like replacement
Cost risk	Switchboard, wiring, circuit capacity	Tank size, valves, access, drainage

For many whole-home replacements, Electric Hot Water Systems are more common than instant electric systems.

Instant electric vs heat pump hot water replacement cost

Instant electric and heat pump hot water are both electric, but they work very differently.

Feature	Instant electric	Heat pump hot water
Heating method	Electric element heats water on demand	Transfers heat from air into stored water
Tank	No	Yes
Upfront product cost	Varies by model	Usually higher than standard electric storage
Electrical demand	Can be high	Usually different electrical requirements
Outdoor airflow	Usually not the main factor	Very important
Condensate drainage	Usually not the same requirement	Required
Best suited to	Compact or point-of-use applications	Efficient electric whole-home hot water where site suits

Choose Heat Pump Hot Water Systems if you want an efficient electric hot water upgrade and the property has suitable outdoor airflow, condensate drainage, electrical setup and noise placement.

Choose instant electric only where flow rate and electrical supply suit the application.

Instant electric vs instant gas replacement cost

Instant electric and instant gas both heat water on demand, but they have different installation requirements.

Instant electric may suit:

Homes or rooms without gas
Point-of-use applications
Compact spaces
Small fixtures
Carefully assessed low-demand setups
Properties with suitable electrical capacity

Instant gas may suit:

Homes already connected to natural gas or LPG
Customers wanting compact continuous flow gas hot water
Properties with suitable gas pipe sizing
Homes with suitable water pressure
Higher hot water demand where gas supply supports it

Compare Instant Gas Hot Water Systems if the home already has suitable natural gas or LPG.

Natural gas and LPG are not interchangeable. Gas work must be completed by a licensed gas fitter.

Like-for-like instant electric replacement

A like-for-like instant electric replacement may be more straightforward when:

The old unit was also instant electric
The application is the same
The flow rate requirement is similar
The electrical supply is suitable
The switchboard can support the unit
Pipework is suitable
Water pressure is suitable
Access is easy
The old unit can be removed easily
The installation is compliant

Even then, a licensed electrician and plumber may need to confirm the replacement is suitable.

Replacing electric storage with instant electric

Changing from electric storage to instant electric is not always simple.

You may need to check:

Whether instant electric can meet whole-home demand
Switchboard capacity
Circuit requirements
Cable size
Electrical upgrade requirements
Water pressure
Flow rate
Temperature rise
Number of outlets
Number of bathrooms
Shower usage
Compliance requirements

For many homes, replacing electric storage with another storage system or upgrading to heat pump hot water may be more practical than changing to instant electric.

Replacing gas hot water with instant electric

Changing from gas hot water to instant electric can be more complex than it first appears.

You may need to consider:

Removing or decommissioning the gas system
Electrical supply upgrades
New circuit requirements
Switchboard capacity
Pipework changes
Water pressure
Flow rate requirements
Whether instant electric can meet household demand
Old unit removal
Disposal
Compliance work

If the home already has suitable gas and higher hot water demand, instant gas may remain more practical.

Replacing heat pump hot water with instant electric

Changing from heat pump hot water to instant electric is a major system-type change.

A heat pump stores hot water in a tank. Instant electric heats water as it flows.

Before switching, check:

Household demand
Whether stored hot water is still preferred
Electrical capacity
Number of outlets
Shower flow rates
Water pressure
Installation location
Whether multiple instant electric units are needed
Removal of the old heat pump
Disposal
Compliance requirements

This change should be assessed carefully before ordering.

Point-of-use instant electric replacement

Instant electric systems are often most suitable as point-of-use water heaters.

Point-of-use applications may include:

Hand basins
Small sinks
Office kitchenettes
Granny flats where demand is low
Workshops
Sheds
Compact spaces
Remote fixtures far from the main hot water unit
Small commercial wash areas where allowed and suitable

Point-of-use systems can reduce the need to run long hot water pipework, but electrical and plumbing requirements still matter.

Whole-home instant electric replacement

Whole-home instant electric is more demanding than point-of-use instant electric.

Before choosing instant electric for a whole home, check:

Number of bathrooms
Shower flow rates
Whether multiple showers run at once
Required temperature rise
Electrical supply
Switchboard capacity
Cable size
Circuit requirements
Water pressure
Manufacturer specifications
Installer advice

Do not assume a compact instant electric unit can replace a full-size household hot water system.

Flow rate and replacement cost

Flow rate affects whether an instant electric system can meet demand.

A system used for a hand basin has very different needs from a system expected to supply a shower.

Flow rate considerations include:

Outlet type
Tap flow rate
Shower flow rate
Number of outlets
Whether outlets run at the same time
Incoming water temperature
Desired outlet temperature
Electrical capacity
Manufacturer ratings

A higher-flow instant electric system may cost more and require more electrical capacity.

Temperature rise and replacement cost

Temperature rise means how much the unit needs to increase the water temperature.

For example, water entering the unit at a lower temperature needs more heating to reach a comfortable shower temperature.

Temperature rise affects:

Flow rate
Electrical demand
Unit suitability
User experience
Whether the system can serve a shower
Whether the system is better suited to a hand basin

A model that works for a small sink may not be suitable for a shower or multiple outlets.

Electrical capacity cost factors

Electrical capacity is one of the biggest instant electric replacement cost factors.

Cost can increase if the job needs:

New circuit
Switchboard upgrades
Larger cable
Electrical isolation changes
Safety switch updates
Load assessment
Metering changes
Electrical compliance work
Licensed electrician involvement

Instant electric should not be ordered until electrical suitability is confirmed.

Switchboard cost factors

Switchboard capacity can affect whether instant electric is practical.

Cost may increase if:

The switchboard is old
There is no spare capacity
A larger circuit is required
Safety switches need attention
Existing wiring is undersized
The property has limited electrical capacity
Other major appliances already use significant load

A compact unit on the wall does not mean a simple electrical job.

Water pressure cost factors

Instant electric systems need suitable water flow and pressure.

Performance can be affected by:

Low water pressure
Old pipework
Restricted valves
Multiple outlets running at once
Long pipe runs
Flow restrictors
Incorrect unit sizing
Poor fixture selection

If hot water pressure has been poor, diagnose the issue before choosing a replacement.

Pipework cost factors

Pipework changes can affect replacement cost.

Extra work may include:

Adjusting hot and cold water connections
Moving the unit
Changing pipe routes
Replacing old fittings
Improving access
Connecting to a different fixture
Correcting old non-compliant work
Removing old storage tank pipework
Installing point-of-use pipework

Even a small water heater can involve extra plumbing work if the location changes.

Access cost factors

Access can affect replacement cost.

Cost may increase if:

The system is inside a tight cupboard
The unit is under a bench
Cabinetry restricts access
The old unit is difficult to remove
Pipework is hard to reach
Electrical work is difficult to access
Extra labour is needed
The installation is in a unit, high-rise or commercial space

Good access helps reduce surprises.

Old unit removal and disposal

Old unit removal and disposal may or may not be included depending on the selected option.

Cost may vary depending on:

Whether the old system is a small instant unit or a large storage tank
Access
Weight
Location
Stairs
Disposal requirements
Whether disconnection is included
Whether the job is supply only or installed where available

Check removal and disposal before ordering.

Instant electric brand and model cost differences

Brand and model can affect product price, warranty terms, electrical requirements, flow rate, dimensions and installation needs.

Installed Today’s homepage-linked hot water brands worth comparing include:

Compare by application, electrical requirement, flow rate and warranty terms, not brand name alone.

Stiebel Eltron instant electric replacement cost factors

Stiebel Eltron Hot Water Systems are commonly compared by customers looking at instant electric, compact electric and premium electric hot water options.

Stiebel Eltron may suit:

Instant electric comparisons
Point-of-use applications
Compact spaces
Units and small fixtures
Homes with suitable electrical capacity
Customers wanting a premium electric brand comparison

Before choosing Stiebel Eltron, confirm flow rate, temperature rise, electrical requirements, installation location and suitability for the intended use.

Rheem electric replacement cost factors

Rheem Hot Water Systems are commonly compared across electric storage, heat pump and gas hot water.

Rheem may suit:

Electric storage replacements
Heat pump comparisons
Customers wanting a major hot water brand
Family-sized electric hot water systems
Homes comparing instant electric against storage options

Before choosing Rheem, check system type, tank size or flow requirements, dimensions, electrical setup and warranty terms.

Rinnai electric replacement cost factors

Rinnai Hot Water Systems are often compared across gas, electric and heat pump hot water options.

Rinnai may suit:

Customers comparing multiple hot water types
Electric storage replacement
Heat pump comparisons
Homes already familiar with Rinnai hot water
Customers comparing electric and gas pathways

Check the exact product type before ordering. Rinnai gas, electric and heat pump systems have different installation requirements.

Instant electric for units and townhouses

Instant electric may suit some units and townhouses, but only where electrical capacity and application suit.

Before choosing instant electric for a unit or townhouse, check:

Body corporate or strata requirements
Switchboard capacity
Electrical supply
Fixture demand
Cabinet space
Access
Water pressure
Drainage
Existing hot water system type
Whether electric storage is more practical

A small compact unit can be useful, but whole-home suitability should be confirmed.

Instant electric for granny flats

Instant electric may suit some granny flats where demand is low and electrical supply supports the system.

Before choosing, check:

Number of occupants
Number of fixtures
Shower use
Kitchen use
Electrical capacity
Water pressure
Pipework route
Whether a small storage system may be more reliable
Whether heat pump or electric storage is more suitable

Granny flats can vary widely, so sizing should be based on real use.

Instant electric for renovations

A renovation is a good time to assess hot water properly.

Instant electric may suit:

Additional hand basins
Remote fixtures
Small kitchenettes
Compact additions
New utility areas
Carefully assessed low-demand spaces

Before choosing, confirm:

Electrical supply
Switchboard capacity
Fixture flow rates
Pipe routes
Cabinet space
Service access
Compliance requirements
Whether the main home still needs storage hot water

Do not leave instant electric selection until after plumbing and electrical rough-in.

Instant electric for sheds and workshops

Instant electric may suit sheds and workshops where hot water demand is limited.

It may be considered for:

Hand washing
Utility sinks
Small kitchenette areas
Light-use wash stations
Remote fixtures
Low-demand applications

Before ordering, check:

Electrical supply to the shed
Water pressure
Fixture type
Weather protection
Installation location
Compliance requirements
Whether the unit is suitable for the intended use

Sheds often have limited electrical capacity, so this must be checked.

Instant electric for commercial-style small applications

Some small business or light commercial applications may consider instant electric for limited hot water needs.

Examples may include:

Staff kitchenettes
Hand basins
Small wash areas
Utility sinks

Before choosing, check:

Hot water demand
Flow rate
Electrical capacity
Compliance requirements
Fixture count
Usage frequency
Maintenance access
Whether a commercial-grade solution is needed

Commercial requirements can differ from household use, so installer advice is important.

What may be included in instant electric replacement?

Inclusions vary by product, selected option and installation pathway.

Possible inclusions may include:

Instant electric hot water unit
Standard connection where installed option is selected
Basic commissioning
Basic plumbing connection where included
Old unit removal where included
Disposal where included

Do not assume electrical upgrades, new circuits, switchboard work, pipework changes, removal, disposal or compliance upgrades are included.

Check product and service details carefully.

What may not be included?

Extra costs may include:

Electrical circuit work
Switchboard upgrades
New cable
Isolation changes
Safety switch work
Plumbing changes
Valve changes
Relocation
Cabinetry work
Old unit removal
Disposal
Difficult access
Compliance upgrades
Additional materials
Testing and certification where required

This is why two homes buying the same instant electric system can have different total costs.

Maintenance costs after replacement

Instant electric systems still need checks and maintenance.

Maintenance may include:

Leak checks
Electrical safety checks where required
Flow checks
Filter or inlet screen checks where applicable
Error code checks
Scale checks depending on water quality
General system inspection
Manufacturer-recommended servicing

Do not remove covers, touch wiring or attempt internal repairs yourself.

Signs your instant electric system needs replacing

Replacement may be worth considering if the unit is:

Not heating properly
Tripping power
Showing error codes
Leaking
Corroded
Struggling with flow
Too small for the application
Requiring repeated repairs
No longer compliant
Very old
Not supported by available parts

If the issue is electrical, use a licensed electrician.

Repair vs replacement cost

Repair may make sense if:

The unit is relatively new
The fault is minor
Parts are available
Warranty may apply
The system is correctly sized
Electrical supply is suitable
The installation is otherwise compliant

Replacement may make sense if:

The unit is old
Repairs are frequent
Parts are unavailable
The system is undersized
The application has changed
Electrical upgrades are required anyway
The installation is no longer compliant
A different system type would suit better

Sometimes replacing with electric storage or heat pump hot water is more practical than replacing instant electric like-for-like.

Supply-only instant electric hot water systems

Supply-only ordering can suit customers who already have their own licensed plumber or electrician arranged.

Supply only may suit:

Builders
Renovators
Trade customers
Property managers
Homeowners managing their own installation
Customers outside supplied-and-installed service areas
Customers needing a point-of-use product for a planned project

Supply-only product pricing generally does not include installation, valves, old unit removal, disposal, electrical work, switchboard upgrades, pipework changes, cabinetry changes, access upgrades or compliance upgrades unless clearly selected or included.

Before ordering supply only, your licensed installer should confirm the instant electric system suits the property.

Supplied-and-installed instant electric hot water systems

Supplied-and-installed options may be available on selected products in eligible Brisbane and Gold Coast service areas where shown.

This can suit customers who want the product and installation pathway arranged together.

Before ordering supplied and installed, check:

Service area eligibility
Existing system type
Installation inclusions
Electrical work
Switchboard requirements
Circuit requirements
Plumbing changes
Valve requirements
Old unit removal
Disposal
Access
Compliance upgrades
Product suitability

Do not assume every possible site requirement is included. Check the selected product and installation options carefully.

How to reduce instant electric replacement surprises

Before ordering, collect:

Photos of the existing unit
Existing model number
Installation location photos
Switchboard photos if relevant
Electrical supply details
Photos of pipework
Fixture type
Number of outlets
Whether the unit supplies a basin, shower or whole area
Water pressure issues
Access details
Whether you want supply only or installed where available

The more accurate the information, the easier it is to avoid choosing the wrong system.

Common mistake: choosing instant electric because it looks simple

Instant electric units can be compact, but their electrical requirements can be significant.

Always check electrical suitability before ordering.

Common mistake: assuming instant electric suits every shower

Not every instant electric system is suitable for shower use.

Flow rate, temperature rise and electrical capacity must be checked.

Common mistake: trying to replace a whole-home tank without checking demand

A tank system and an instant electric system deliver hot water differently.

Whole-home replacement needs careful assessment.

Common mistake: ignoring switchboard capacity

Switchboard capacity can determine whether instant electric is practical.

Do not order based on product size alone.

Common mistake: comparing only the unit price

The product price is not the total replacement cost.

Electrical work, switchboard changes, pipework and compliance upgrades can affect the final cost.

Common mistake: ignoring water pressure and flow

Instant electric systems need suitable water flow.

Poor water pressure can affect user experience and performance.

Common mistake: choosing instant electric when heat pump would suit better

If the goal is efficient whole-home electric hot water, heat pump hot water may be a better comparison where the property has suitable airflow, drainage and space.

Common mistake: DIY instant electric installation

Instant electric installation can involve plumbing, electrical work, pressure control, scalding safety and compliance.

DIY installation can create:

Electrical risks
Water leaks
Scalding risks
Tripping power
Warranty issues
Insurance problems
Non-compliant work
Poor performance
Property damage

Use the right licensed professionals.

Final verdict: how much should you budget for instant electric hot water replacement?

Instant electric hot water replacement cost depends on the model, flow rate, application, electrical supply, switchboard capacity, circuit requirements, water pressure, pipework, access, old unit removal, disposal and compliance requirements.

A like-for-like point-of-use replacement can be relatively straightforward where the existing setup is suitable.

Changing from electric storage, heat pump or gas hot water to instant electric can be more complex and may not suit every home.

Start by comparing Instant Electric Systems, Electric Hot Water Systems, Heat Pump Hot Water Systems, broader Hot Water Systems, Gas Hot Water Systems and Instant Gas Hot Water Systems.

The best instant electric replacement is not always the smallest or cheapest unit. It is the system that matches the fixture, flow rate, electrical setup, water pressure, installation location and long-term hot water needs.

Long-tail FAQs

How much does it cost to replace an instant electric hot water system?

Instant electric replacement cost depends on the model, flow rate, application, electrical supply, switchboard capacity, circuit requirements, plumbing changes, access, removal, disposal and compliance needs.

Is instant electric cheaper than electric storage?

Not always. Instant electric may have a lower product cost in some applications, but electrical work can make the total replacement cost higher.

Can instant electric hot water run a whole house?

Sometimes, but it needs careful assessment. Whole-home instant electric requires suitable electrical capacity, flow rate, water pressure and temperature rise.

Is instant electric good for showers?

Only selected instant electric systems suit showers, and the electrical supply must support the required flow and temperature rise.

Is instant electric good for a hand basin?

Instant electric can be a good option for some hand basins and point-of-use applications where the electrical and plumbing setup suits.

Can I replace electric storage with instant electric?

Sometimes, but it is not always practical. Electrical capacity, switchboard requirements, flow rate and household demand must be checked.

Is heat pump better than instant electric?

For whole-home electric hot water, heat pump hot water may be a better option where the property has suitable outdoor airflow, condensate drainage and space. Instant electric may suit compact or point-of-use applications.

Does instant electric need special wiring?

Many instant electric systems require dedicated circuits or specific electrical capacity. A licensed electrician should confirm the requirements before ordering.

What brands make instant electric hot water systems?

Stiebel Eltron is commonly compared for instant electric and compact electric hot water. Other hot water brands may offer electric storage, heat pump or gas alternatives depending on model range.

Can I install instant electric hot water myself?

No. Instant electric hot water installation should be completed by licensed professionals. Plumbing, electrical work and compliance requirements can create safety and warranty issues if handled incorrectly.

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