Storage vs Instant Hot Water Systems: Which Is Better?

Choosing between a storage and instant hot water system depends on your household size, energy source, available space, budget, daily hot water demand and replacement setup. Storage hot water systems heat and keep water in a tank, while instant hot water systems heat water as it flows through the unit.

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

Quick Answer: Is Storage or Instant Hot Water Better?

Storage hot water may be better if you want a traditional tank-style system, already have an electric, gas or heat pump storage unit, and your household demand suits a stored supply of hot water.

Instant hot water may be better if you want water heated on demand, have the right energy source, and the unit’s flow rate suits your household demand.

As a general guide:

• Choose a storage hot water system if you want a tank-style system for regular household use.

• Choose an electric storage system if your home already uses electric hot water and you want a straightforward replacement.

• Choose a heat pump if you want an efficient electric storage option and have suitable outdoor space and airflow.

• Choose gas storage if your home already has gas storage and you want a traditional replacement.

• Choose instant gas if your home has natural gas or LPG and you want continuous flow hot water.

• Choose instant electric only for suitable point-of-use applications where the electrical requirements and flow demand match the product.

The best choice is not simply storage vs instant. It is the system that matches your energy source, household size, hot water demand, space, flow rate, tank size and replacement requirements.

Storage vs Instant Hot Water at a Glance

Both storage and instant systems can work well. The right choice depends on your home, not just the system type.

What Is a Storage Hot Water System?

A storage hot water system heats water and keeps it inside a tank until hot water is needed. When you turn on a hot tap, hot water comes from the stored supply.

Common storage hot water systems include:

• Electric hot water systems

• Gas hot water systems

• Heat pump hot water systems

Storage systems are usually compared by tank capacity in litres, recovery rate, energy source, dimensions, connection positions, pressure rating and household suitability.

A storage system may suit homes where:

• A tank-style system is already installed

• A like-for-like replacement is preferred

• The household wants stored hot water

• The available space suits a tank

• Tank capacity can be matched to daily demand

• The existing connection layout suits another storage unit

Storage hot water is common because it is familiar, widely available and suitable for many replacement situations.

What Is an Instant Hot Water System?

An instant hot water system heats water as it flows through the unit. It does not keep a large tank of hot water ready.

Common instant hot water systems include:

• Instant gas hot water systems

• Instant electric hot water systems

Instant gas systems are commonly used for whole-home continuous flow gas hot water where the property has natural gas or LPG. Instant electric systems are generally more suited to specific point-of-use applications where the electrical requirements and flow demand match the product.

An instant system may suit homes where:

• On-demand hot water is preferred

• A large storage tank is not ideal

• Natural gas or LPG is available for instant gas

• The selected flow rate suits household demand

• The intended use suits instant electric

• The system location and connection requirements are suitable

Instant hot water is not automatically better than storage. The system must be sized and selected correctly for the property.

Electric Storage vs Instant Electric Hot Water

Electric storage and instant electric hot water systems both use electricity, but they are used differently.

An electric storage system heats and stores water in a tank. It is commonly used for whole-home hot water supply. An instant electric system heats water as it flows through the unit and is usually more suited to compact point-of-use applications.

For most homes replacing an existing electric tank, electric hot water systems are the main category to compare. For compact hot water needs, instant electric hot water systems may be worth reviewing.

Gas Storage vs Instant Gas Hot Water

Gas storage and instant gas hot water both use natural gas or LPG, but they deliver hot water differently.

Gas storage systems heat and store water in a tank. Instant gas systems heat water as it flows through the unit.

Choose gas hot water systems if you want to compare gas storage options. Choose instant gas hot water systems if you want continuous flow gas hot water and the selected flow rate suits the home.

Heat Pump Hot Water: Storage With a Difference

A heat pump hot water system is still a storage system because it heats and stores water in a tank. The difference is how it heats the water.

Instead of relying only on a standard electric element, a heat pump uses heat from the surrounding air to help heat the stored water. This makes it a common option for households comparing energy-efficient electric hot water.

Heat pump hot water may suit homes where:

• The current system is electric storage

• An efficient electric storage option is preferred

• Outdoor space is available

• Airflow around the unit is suitable

• Noise considerations can be managed

• The tank size suits household demand

Heat pumps should be compared carefully because location matters. Tank size, airflow, noise rating, dimensions and product specifications all need to be checked before ordering.

Storage vs Instant Hot Water for Like-for-Like Replacement

If you are replacing an old hot water system, the current setup is usually the best starting point.

A storage replacement may be practical if:

• The current system is electric storage, gas storage or heat pump

• The old tank size worked well

• The existing location suits another tank

• The household wants a familiar replacement

• The connection positions can be matched

• The current system type still suits the home

An instant replacement may be practical if:

• The current system is already instant gas

• The existing flow rate suited the household

• Natural gas or LPG is available

• The selected model matches the correct gas type

• The current wall location still works

• Controller requirements are checked

Changing from storage to instant, or instant to storage, can involve different connection requirements. Always compare the full setup before ordering.

Storage vs Instant Hot Water for Families

Family homes usually need stronger hot water performance than smaller households. Both storage and instant systems can suit families when sized correctly.

Storage may suit families if:

• A larger tank is selected

• Recovery rate suits household demand

• Back-to-back showers are common

• The home already uses electric, gas or heat pump storage

• Stored hot water is preferred

Instant gas may suit families if:

• The home has natural gas or LPG

• The selected flow rate suits the number of bathrooms

• Multiple outlets may be used at once

• A continuous flow gas system is preferred

• A large tank is not ideal

For families, the main question is not just storage or instant. It is whether the system can handle real daily use, including showers, baths, kitchen use, laundry use and peak demand.

Storage vs Instant Hot Water for Small Homes

Small homes, units and townhouses may not need the same capacity as larger homes, but the system still needs to suit daily usage.

Storage may suit a small home if:

• The property already has an electric or gas storage tank

• A smaller tank suits household demand

• Space is available for the unit

• A simple replacement is preferred

• The home does not have gas

Instant hot water may suit a small home if:

• Natural gas or LPG is available for instant gas

• The household demand suits the selected flow rate

• A compact wall-mounted option is preferred

• A point-of-use instant electric unit is suitable for the application

Do not choose the smallest system automatically. Shower habits, hot water timing and the number of occupants still matter.

Storage vs Instant Hot Water for Rental Properties

Rental properties need practical hot water systems that suit the expected number of occupants, property layout and existing setup.

Storage may suit a rental if:

• The property already has storage hot water

• A like-for-like replacement is preferred

• The tank size suits the number of bedrooms and bathrooms

• The system is familiar and straightforward

• The existing location works

Instant gas may suit a rental if:

• The property already uses gas

• Continuous flow hot water is preferred

• The selected flow rate suits expected tenant demand

• The correct natural gas or LPG model is chosen

• The existing setup supports the replacement

For rentals, avoid choosing by purchase price alone. The system needs to suit likely tenant use and the property’s existing services.

Storage vs Instant Hot Water for Renovations

Renovations are a good time to review your hot water setup. A new bathroom, larger bath, kitchen upgrade or laundry renovation can increase hot water demand.

Storage may suit a renovation if:

• A tank-style system is already planned

• Household demand suits a storage tank

• A heat pump is being considered

• The system location can be planned properly

• Tank capacity can be matched to the finished home

Instant gas may suit a renovation if:

• Natural gas or LPG is available

• Continuous flow hot water is preferred

• A large storage tank is being removed

• Wall space is available for the unit

• The selected flow rate suits the upgraded layout

For renovation projects, also check whether you need valves, pipework and fittings as part of the wider hot water setup.

Storage Hot Water Pros and Cons

Potential Advantages of Storage Hot Water

Storage hot water systems can be a practical choice for many homes.

Potential advantages include:

• Familiar tank-style design

• Common for like-for-like replacement

• Available in electric, gas and heat pump options

• Broad range of tank sizes

• Suitable for regular household use

• Easy to compare by capacity and specifications

• Available from recognised brands

Potential Disadvantages of Storage Hot Water

Storage hot water is not the best option for every home.

Potential disadvantages include:

• Requires space for a tank

• Tank size must be chosen carefully

• A small tank may run out quickly

• A larger tank may cost more than needed

• Recovery rate varies by model

• Stored water can lose heat over time

• Replacement dimensions and connection positions must be checked

The best storage system is one that matches the household’s demand without being undersized or oversized.

Instant Hot Water Pros and Cons

Potential Advantages of Instant Hot Water

Instant hot water systems can suit the right home and application.

Potential advantages include:

• Heats water on demand

• No large storage tank for instant gas systems

• Compact wall-mounted gas options available

• Continuous flow gas hot water where correctly sized

• Good option for some gas replacement projects

• Instant electric options for suitable point-of-use applications

Potential Disadvantages of Instant Hot Water

Instant hot water is not automatically suitable for every home.

Potential disadvantages include:

• Instant gas requires natural gas or LPG

• Correct gas type must be selected

• Flow rate must suit household demand

• Gas supply must be suitable

• Instant electric has specific electrical requirements

• Some systems may not suit whole-home demand

• Connection work must be completed by licensed tradespeople

Instant systems need careful product selection. The wrong flow rate, gas type or application can create performance problems.

Storage vs Instant Hot Water Costs

The cost of storage and instant hot water systems depends on system type, brand, size, flow rate, energy source and replacement requirements.

Storage hot water costs can vary based on:

• Tank capacity

• Electric, gas or heat pump type

• Brand and model

• Recovery rate

• Pressure rating

• Product warranty information

• Required valves and fittings

• Delivery requirements

Instant hot water costs can vary based on:

• Instant gas or instant electric type

• Flow rate in L/min

• Natural gas or LPG model

• Controller options

• Brand and model

• Connection requirements

• Required valves and fittings

• Product warranty information

A cheaper product is not always the better option. The selected system still needs to suit the home, energy source, hot water demand and replacement setup.

Storage vs Instant Hot Water Running Costs

Running costs vary depending on energy prices, usage patterns, system efficiency, tank size, flow rate and household demand.

Storage running costs may be affected by:

• How much water is heated and stored

• Tank size

• Heat loss

• Recovery rate

• Electricity or gas prices

• Heat pump efficiency where relevant

• Household usage patterns

Instant running costs may be affected by:

• Flow rate

• Hot water usage time

• Gas type

• Electricity requirements

• Number of outlets used

• Product efficiency

• Household demand

A heat pump may use less electricity than standard electric storage in suitable conditions. Instant gas may suit homes with suitable gas supply and correctly matched flow rate. Standard storage may still be practical for many like-for-like replacements.

How to Choose Between Storage and Instant Hot Water

1. Start With Your Current System

Check what is already installed. If the current system worked well, a similar type may be the easiest place to start.

2. Check Your Energy Source

Confirm whether your home uses electricity, natural gas or LPG. The available energy source will narrow your choices.

3. Decide Whether You Want a Tank

If you are comfortable with a tank-style system, storage may suit. If you want to avoid a large storage tank and have gas available, instant gas may be worth comparing.

4. Compare Tank Size or Flow Rate

Storage systems are compared by tank capacity in litres. Instant gas systems are compared by flow rate in L/min.

5. Check Available Space

Storage systems need room for a tank. Instant gas systems need suitable wall space. Heat pumps need space and airflow.

6. Think About Peak Demand

Consider when the household uses hot water most. Back-to-back showers, baths, laundry and kitchen use all affect system choice.

7. Check Required Valves and Fittings

Some hot water replacements need extra valves, pipework or fittings. Check the full order before buying.

8. Confirm Licensed Trade Requirements

Hot water systems involve plumbing, gas and electrical work. These should be handled by appropriately licensed tradespeople.

Common Mistakes When Comparing Storage and Instant Hot Water

Comparing Litres and L/min as the Same Thing

Storage systems are measured by tank capacity in litres. Instant gas systems are measured by flow rate in L/min. These are different sizing methods.

Choosing Instant Gas Without Checking Gas Type

Natural gas and LPG systems are not interchangeable. Always confirm gas type before ordering.

Choosing Storage Without Checking Recovery Rate

Tank capacity matters, but recovery rate also affects performance. This is especially important for busy households.

Assuming Instant Electric Suits Whole-Home Use

Instant electric systems are often better suited to specific point-of-use applications. Always check electrical requirements and product suitability.

Choosing the Cheapest System Only

A cheaper system is not good value if it does not suit the property, household demand or connection layout.

Forgetting Dimensions

A system may have the right capacity or flow rate but still not fit the available space.

Forgetting Valves and Fittings

Some replacements require compatible valves, pipework or fittings. Check the full order before purchasing.

Ignoring the Current Setup

Changing system type can be more involved than like-for-like replacement. Start by checking what is already installed.

Buyer Checklist: Storage vs Instant Hot Water

Before choosing between storage and instant hot water, check:

• Current hot water system type

• Current brand and model

• Current tank size or flow rate

• Electricity, natural gas or LPG

• Household size

• Number of bathrooms

• Daily hot water demand

• Shower habits

• Bath use

• Kitchen hot water use

• Laundry hot water use

• Tank capacity if choosing storage

• Flow rate in L/min if choosing instant gas

• Electrical requirements if choosing instant electric

• Recovery rate if choosing storage

• Available space

• Heat pump airflow if relevant

• Noise rating if choosing heat pump

• Connection positions

• Pressure rating

• Required valves and fittings

• Delivery access

• Warranty information

• Product specifications

Brands to Compare

Hot Water Outlet lists recognised hot water brands so buyers can compare storage and instant systems by type, energy source, size and product specifications.

Depending on the system you need, you may want to compare:

• Rheem hot water systems

• Rinnai hot water systems

• Dux hot water systems

• Bosch hot water systems

• Vulcan hot water systems

• iStore hot water systems

• Stiebel Eltron hot water systems

• Envirosun hot water systems

• Emerald Energy hot water systems

Brand can help narrow your choice, but the final decision should still come down to energy source, sizing, flow rate, dimensions, connection positions and product suitability.

So, Should You Choose Storage or Instant Hot Water?

Choose storage hot water if you want a tank-style system, already have electric, gas or heat pump storage, and the tank size can be matched to your household demand.

Choose instant hot water if you want on-demand heating and the system suits your energy source, flow demand and application. For whole-home instant hot water, instant gas is usually the main category to compare where natural gas or LPG is available. Instant electric is generally more suited to specific point-of-use applications.

The best system is the one that suits your home, not just the category. Compare your current setup, household demand, available space, energy source and product specifications before ordering.

Compare Storage and Instant Hot Water Systems Online

Hot Water Outlet makes it easier to compare storage and instant hot water systems online by type, brand, size, energy source and household suitability.

Start with:

• Hot Water Systems

• Electric Hot Water Systems

• Heat Pump Hot Water Systems

• Gas Hot Water Systems

• Instant Gas Hot Water Systems

• Instant Electric Hot Water Systems

• Valves, Pipework and Fittings

FAQs About Storage vs Instant Hot Water Systems

Is storage or instant hot water better?

Storage hot water may be better for homes wanting a tank-style system and a familiar replacement. Instant hot water may be better for homes wanting on-demand hot water where the selected system suits the energy source, flow demand and application.

What is the difference between storage and instant hot water?

Storage hot water systems heat and store water in a tank. Instant hot water systems heat water as it flows through the unit. Storage systems are usually compared by tank capacity, while instant gas systems are compared by flow rate in L/min.

Is instant gas better than gas storage hot water?

Instant gas may be better if you want continuous flow gas hot water without a large storage tank. Gas storage may be better if you want a traditional gas tank replacement. The better option depends on gas type, household demand, available space and replacement setup.

Is electric storage better than instant electric hot water?

Electric storage is usually more suitable for whole-home electric hot water. Instant electric is generally more suited to specific point-of-use applications where the electrical requirements and flow demand match the product.

Is a heat pump a storage or instant hot water system?

A heat pump is a storage hot water system. It heats and stores water in a tank, but uses heat from the surrounding air to help heat the water.

What size storage hot water system do I need?

The right storage size depends on household size, number of bathrooms, shower habits, bath use, laundry use, kitchen use and recovery rate. Storage systems are measured by tank capacity in litres.

What size instant gas hot water system do I need?

Instant gas hot water systems are sized by flow rate in L/min. The right flow rate depends on the number of people, bathrooms, hot water outlets and whether multiple outlets are used at the same time.

Can I replace storage hot water with instant gas?

Some homes may be able to replace storage hot water with instant gas, but suitability depends on gas availability, gas type, flow rate requirements, location, connection changes and household demand. Speak with a licensed gas fitter if you are unsure.

Can I replace instant gas with storage hot water?

Some homes may be able to change from instant gas to storage, but it depends on energy source, available space, connection requirements and household demand. Compare the full setup before ordering.

Do storage and instant systems need valves and fittings?

Some storage and instant hot water replacements require valves, pipework or fittings depending on system type, pressure rating and connection layout. Browse valves, pipework and fittings and confirm compatibility before ordering.

Can I install storage or instant hot water 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 Storage or Instant Hot Water System

Storage and instant hot water systems can both be good options when matched to the right property. Storage may suit homes wanting a tank-style system. Instant gas may suit homes with natural gas or LPG that want continuous flow hot water. Instant electric may suit specific point-of-use applications where suitable.

Browse hot water systems online with Hot Water Outlet to compare storage, instant gas, instant electric, heat pump, gas and electric hot water systems by brand, size, energy source and product specifications.