Instant Electric Hot Water System: Is It Right for Your Home?

Nov 8, 2024

An instant electric hot water system heats water as it flows through the unit, instead of storing hot water in a tank. This can make instant electric hot water useful for small point-of-use applications, compact spaces, offices, granny flats, kitchenettes and selected low-demand fixtures.

For whole-home hot water, instant electric is not always the best choice. It can have high electrical demand, may require significant electrical upgrades and may not suit multiple showers or high-flow fixtures. Before buying one, it is important to compare instant electric with electric storage, gas hot water, instant gas and heat pump hot water.

Installed Today makes it easy to compare instant electric hot water systems, electric hot water systems, gas hot water systems, instant gas hot water systems, heat pump hot water systems and broader hot water systems online. Supply-only ordering is available across major Australian metro areas, with selected supplied-and-installed options available on eligible products in Brisbane and Gold Coast service areas.

Quick Answer: Are Instant Electric Hot Water Systems Worth It?

An instant electric hot water system may be worth it for small, targeted hot water use where the electrical supply, flow rate and fixture demand suit the unit.

As a general guide:

Instant electric hot water is best suited to point-of-use applications
It can be useful for small sinks, kitchenettes, offices, workshops and low-demand fixtures
It does not need a large storage tank
Whole-home instant electric can require substantial electrical capacity
It may not suit multiple showers or high-flow household use
Electrical requirements must be checked before ordering
A licensed electrician may be required
Supply-only pricing generally covers the product only
Electric storage, heat pump, gas storage or instant gas may be better for full-home hot water

Before ordering supply only, confirm the selected model, power requirements, flow rate, water pressure, installation location and electrical suitability with your licensed installer or electrician.

What Is an Instant Electric Hot Water System?

An instant electric hot water system heats water only when hot water is being used. When a tap is turned on, water flows through the unit and an electric heating element heats the water as it passes through.

This is different from an electric storage hot water system, which heats and stores a tank of water ready for use later.

Instant electric systems are also called:

Electric instantaneous hot water systems
Electric continuous flow hot water systems
Tankless electric hot water systems
Point-of-use electric hot water units
On-demand electric hot water systems

The key difference is that instant electric systems do not store a large volume of hot water.

How Instant Electric Hot Water Works

An instant electric hot water system generally works like this:

A hot tap or fixture is turned on
The unit detects water flow
The electric heating element activates
Cold water passes through the heating chamber
Water is heated as it flows through the unit
Hot water is delivered to the fixture
The unit stops heating when the tap is turned off

This means the unit only heats water when there is demand. However, the amount of hot water it can deliver depends on electrical power, water flow rate and incoming water temperature.

Instant Electric vs Electric Storage Hot Water

Electric hot water systems are commonly storage systems. They use an electric element to heat water inside a tank.

System Type	How It Works	Best Suited To
Instant electric	Heats water as it flows through the unit	Small point-of-use applications or selected low-demand fixtures
Electric storage	Stores heated water in a tank	Whole-home hot water, simple replacements and homes without gas

Electric storage may suit:

Family homes
Rental properties
Whole-home hot water
Homes without gas
Like-for-like electric replacements
Homes needing a larger stored volume of hot water

Instant electric may suit:

Small sinks
Kitchenettes
Offices
Workshops
Low-demand fixtures
Compact spaces
Point-of-use hot water

For most full-home hot water replacements, electric storage is often easier to compare than instant electric.

Common electric storage categories include:

Popular electric storage options include:

Instant Electric vs Instant Gas Hot Water

Instant electric and instant gas systems both heat water on demand, but they use different energy sources and suit different homes.

Instant gas hot water systems use natural gas or LPG. Instant electric systems use electricity.

Option	Energy Source	Common Use
Instant electric	Electricity	Small point-of-use applications, compact spaces, low-demand fixtures
Instant gas	Natural gas or LPG	Whole-home continuous flow hot water where gas supply suits

Instant gas may suit:

Homes with natural gas or LPG
Homes wanting continuous flow hot water
Homes with suitable gas pipe sizing
Homes with suitable water pressure
Homes with outdoor wall space
Some family homes when correctly sized

Instant electric may suit:

Small under-sink applications
Kitchenettes
Office sinks
Workshops
Granny flats with low demand
Selected point-of-use fixtures

For whole-home hot water, instant gas is often more practical than instant electric where the home already has suitable gas supply.

Relevant instant gas categories include:

Popular instant gas options include:

Natural gas and LPG models are different and not interchangeable.

Instant Electric vs Heat Pump Hot Water

A heat pump hot water system is an electric-style storage system that uses heat from the surrounding air to help heat stored water.

Heat pumps are very different from instant electric systems.

Option	How It Works	Best Suited To
Instant electric	Heats water instantly at the fixture or unit	Small point-of-use hot water
Heat pump	Stores water and heats it using air-source heat pump technology	Whole-home hot water where outdoor space suits

Heat pump hot water may suit:

Homes replacing older electric storage
Energy-focused households
Homes with suitable outdoor space
Homes with clear airflow around the unit
Homes with suitable condensate drainage
Homes with suitable electrical supply
Homes where noise placement is acceptable
Homes with rooftop solar where timer operation may suit

Instant electric may suit:

Small sinks
Low-flow fixtures
Compact applications
Point-of-use locations
Situations where a storage tank is not practical

A heat pump is not automatically the best option for every home, but it is often more relevant than instant electric for whole-home electric hot water.

Relevant heat pump categories include:

Popular heat pump options include:

Best Uses for Instant Electric Hot Water

Instant electric hot water can be useful when hot water is needed at one small location rather than across a whole house.

Good use cases can include:

Office sinks
Kitchenettes
Small commercial sinks
Workshop handwashing
Garages
Sheds
Granny flats with low demand
Outdoor utility sinks, where the unit is suitable
Point-of-use bathroom basins
Small apartments with limited demand
Remote fixtures far from the main hot water unit

The best use is usually low-flow, short-duration hot water close to the point of use.

When Instant Electric May Not Be the Best Choice

Instant electric hot water may not be the right choice for every home.

It may not suit:

Whole-home hot water in larger households
Multiple bathrooms
Multiple showers running at once
High-flow showers
Homes with limited electrical capacity
Homes where switchboard upgrades would be expensive
Long hot water runs
High-demand family use
Properties better suited to storage hot water
Homes with natural gas where instant gas is more practical

If you need hot water for an entire family home, compare electric storage, heat pump, gas storage and instant gas before choosing instant electric.

Electrical Requirements Matter

Electrical capacity is one of the biggest checks for instant electric hot water.

Depending on the model and intended use, an instant electric unit may require:

Dedicated circuit
Suitable cable size
Switchboard capacity
Safety switch protection
High electrical load allowance
Single-phase or three-phase power, depending on the unit
Licensed electrician installation
Compliance with electrical rules

A small under-sink unit may have different requirements from a higher-output unit. Do not assume your existing power point or circuit can support the unit.

Before ordering, confirm:

Voltage
Amperage
Phase requirements
Circuit requirements
Switchboard capacity
Cable route
Isolation requirements
Whether electrical upgrades are needed

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

Flow Rate and Temperature Rise

Instant electric hot water performance depends on flow rate and temperature rise.

Flow rate is how much water moves through the unit. Temperature rise is how much the unit needs to heat the incoming water to reach the desired outlet temperature.

For example, if the incoming water is cooler, the unit needs to work harder to reach the same hot water temperature. This can reduce available flow.

Important checks include:

Required flow rate
Incoming cold water temperature
Desired outlet temperature
Fixture type
Shower vs basin use
Flow restrictors
Electrical capacity
Distance from unit to tap

A unit that suits a hand basin may not suit a shower.

Can Instant Electric Run a Shower?

Some instant electric systems are designed for shower use, but this depends heavily on the model, electrical supply and required flow rate.

Before using instant electric for a shower, confirm:

Whether the unit is rated for shower use
Required power supply
Flow rate at the desired temperature
Incoming water temperature
Water pressure
Cable and circuit requirements
Compliance requirements
Whether a licensed electrician is needed
Whether the household demand is realistic

For many homes, electric storage, heat pump or instant gas may be more practical for shower use.

Can Instant Electric Run a Whole House?

Whole-house instant electric hot water can be challenging because the electrical demand can be high.

It may require:

Large electrical capacity
Dedicated circuits
Switchboard upgrades
Three-phase power in some situations
Careful fixture flow planning
Correct unit sizing
Licensed electrical work
Water pressure checks

This does not mean whole-home instant electric is impossible, but it should be assessed carefully before purchase. For many family homes, storage hot water or instant gas may be more practical.

Point-of-Use Instant Electric Systems

Point-of-use instant electric systems are installed close to the fixture they serve. This can reduce the delay caused by long pipe runs from a distant hot water system.

Point-of-use units may suit:

A single basin
A kitchenette
A staff room
A small handwashing sink
A remote bathroom basin
A low-demand workshop sink

Benefits can include:

Compact size
No large tank
Less waiting at the fixture
Targeted hot water
Space-saving design

However, the unit still needs the correct electrical supply and flow rating.

Space-Saving Benefits

One major reason people compare instant electric hot water systems is space.

Because they do not use a large storage tank, they may suit:

Apartments
Small offices
Kitchenettes
Under-sink areas
Tight service cupboards
Sheds
Compact bathrooms
Granny flats

Space-saving can be useful, but it should not override electrical suitability or flow requirements.

Running Costs and Efficiency

Instant electric systems heat water only when hot water is being used. This can reduce standby heat loss compared with a storage tank.

However, running cost depends on:

Electricity tariff
Water usage
Flow rate
Incoming water temperature
Unit efficiency
Household habits
Electrical demand
Whether the unit is point-of-use or whole-home
Whether another system type would be more suitable

Instant electric is not automatically cheaper to run than gas, heat pump or electric storage. The best option depends on usage and site conditions.

Instant Electric and Solar Power

Some households compare instant electric hot water because they have rooftop solar PV. This can sound appealing, but it needs careful assessment.

Important checks include:

When hot water is used
Solar generation timing
Electrical load of the unit
Whether the system can operate effectively during solar production
Whether battery storage is involved
Whether heat pump hot water would pair better with solar
Whether switchboard capacity suits the unit

For many homes with rooftop solar, heat pump hot water or controlled electric storage may be more practical than high-demand instant electric. The best option depends on the household setup.

Installation Considerations

Instant electric hot water installation can involve plumbing and electrical work.

Before ordering, check:

Installation location
Water pressure
Flow requirements
Distance to fixture
Electrical supply
Switchboard capacity
Cable route
Circuit protection
Ventilation where required
Access for servicing
Indoor or outdoor suitability
Manufacturer clearance requirements
Compliance requirements

Do not install an indoor-only unit outdoors, and do not install an outdoor-only product indoors unless the product is specifically approved for that use.

What Is Not Included in Supply-Only Instant Electric Pricing?

For supply-only products, the listed product price generally covers the product only.

It does not usually include:

Installation labour
Plumbing alterations
Electrical work
Switchboard upgrades
Dedicated circuits
New wiring
New valves
Pipework changes
Drainage changes
Tempering valve upgrades
Pressure limiting valve upgrades
Old unit removal
Disposal
Compliance upgrades
Wall mounting changes
Site assessment

Always check the product page and confirm full site requirements with your licensed installer or electrician before ordering supply only.

Supply-Only vs Supplied-and-Installed

Installed Today offers supply-only ordering across major Australian metro areas. This can suit customers who already have a licensed installer or electrician organised and want to order the product online.

Supply-only may suit you if:

Your installer has confirmed the correct product
Your electrician has checked electrical requirements
The system suits the intended fixture
Flow rate has been checked
Water pressure has been reviewed
Installation location is suitable
You understand what is not included in the product price

Selected supplied-and-installed options are available on eligible products in Brisbane and Gold Coast service areas. Availability depends on the product, address and installation requirements.

Before choosing a supplied-and-installed option, check exactly what is included and what may be extra.

Brisbane and Gold Coast Considerations

For Brisbane and Gold Coast homes, instant electric hot water may be considered for small point-of-use applications, offices, kitchenettes, sheds and compact fixtures.

Common local considerations include:

Existing electrical capacity
Switchboard condition
Whether three-phase power is available where required
Water pressure
Fixture flow rate
Distance from main hot water system
Apartment or townhouse space limits
Outdoor vs indoor installation location
Whether electric storage or heat pump is more practical
Whether supplied-and-installed options are available for the selected product

For full-home hot water, many Brisbane and Gold Coast homes compare electric storage, heat pump and gas hot water before choosing instant electric.

Maintenance for Instant Electric Hot Water

Instant electric systems need maintenance according to the manufacturer’s instructions and water quality conditions.

Maintenance may include:

Checking for leaks
Monitoring outlet temperature
Inspecting visible fittings
Checking for error codes
Descaling where required
Cleaning inlet strainers where fitted
Checking flow performance
Having electrical faults checked by a licensed electrician
Following manufacturer service intervals

Hard water, sediment or poor water quality can affect performance. Pre-filtration may be needed in some situations.

Signs an Instant Electric System Needs Attention

An instant electric hot water system may need inspection if you notice:

No hot water
Water not hot enough
Hot water cutting in and out
Low flow
Tripping circuit breaker
Error codes
Leaks
Burning smell
Unit overheating
Electrical buzzing or unusual noises
Reduced performance over time

Turn the unit off if it appears unsafe, leaking badly or creating electrical concerns.

Common Mistakes When Choosing Instant Electric Hot Water

Assuming It Suits Whole-Home Use

Instant electric is often better for point-of-use applications than full-home hot water.

Ignoring Electrical Requirements

Electrical capacity is a major factor. A unit may need dedicated wiring, switchboard capacity or three-phase power.

Comparing It Only Against Storage Tanks

Instant electric should also be compared with heat pump and instant gas options.

Choosing Based on Size Alone

The right unit depends on flow rate, temperature rise, fixture type and electrical supply.

Using a Small Unit for a Shower

A unit that suits a basin may not suit a shower.

Assuming Supply-Only Includes Installation

Supply-only generally means product only unless installation is selected or clearly shown.

Forgetting Maintenance

Scale, sediment and water quality can affect performance over time.

Before Ordering Checklist

Before ordering an instant electric hot water system, confirm:

Intended use
Point-of-use or whole-home requirement
Fixture type
Required flow rate
Desired outlet temperature
Incoming water temperature
Water pressure
Installation location
Indoor or outdoor suitability
Electrical voltage
Amperage
Single-phase or three-phase requirements
Dedicated circuit needs
Switchboard capacity
Cable route
Whether a licensed electrician is required
Whether a licensed plumber is required
Whether new valves may be needed
Whether the unit is suitable for showers
Whether electric storage, heat pump or gas hot water is more practical
Installer confirmation before buying supply only

Frequently Asked Questions

What is an instant electric hot water system?

An instant electric hot water system heats water as it flows through the unit instead of storing hot water in a tank.

Is instant electric hot water good?

It can be good for small point-of-use applications, low-demand fixtures and compact spaces. It may not be the best option for whole-home family hot water.

Does instant electric hot water use a lot of power?

Instant electric units can have high electrical demand, especially larger models. Electrical requirements must be checked before ordering.

Can instant electric hot water run a shower?

Some models may be designed for shower use, but electrical supply, flow rate, temperature rise and water pressure must be checked carefully.

Can instant electric hot water run a whole house?

Sometimes, but whole-home instant electric can require significant electrical capacity. Electric storage, heat pump or instant gas may be more practical for many homes.

Is instant electric cheaper than electric storage?

Not always. Instant electric may reduce standby heat loss, but running cost depends on usage, tariff, electrical demand and whether the system suits the application.

Is instant electric better than instant gas?

It depends on the home. Instant gas may suit whole-home hot water where gas supply is available. Instant electric may suit small point-of-use hot water where electrical supply suits.

Does instant electric need three-phase power?

Some larger instant electric units may require three-phase power. Smaller point-of-use units may have different requirements. Always check the product specifications.

Can I install instant electric hot water myself?

No. Instant electric systems can involve plumbing and electrical work. Use licensed trades where required.

Does supply-only instant electric pricing include installation?

No. Supply-only generally means product only unless installation is selected or clearly shown. Installation, plumbing work, electrical work, wiring, switchboard upgrades, valves, removal and compliance upgrades are usually separate.

Final Word

An instant electric hot water system can be a practical solution for small point-of-use hot water where space is limited and electrical supply is suitable. It can work well for sinks, kitchenettes, offices, workshops and selected low-demand fixtures.

For full-home hot water, compare instant electric with electric storage, heat pump, gas storage and instant gas systems before ordering. Electrical requirements, flow rate, water pressure and fixture demand are the key checks.

Before ordering supply only through Installed Today, confirm the selected product with your licensed installer or electrician. If choosing a supplied-and-installed option in an eligible Brisbane or Gold Coast service area, check exactly what is included before placing the order.

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