Instant Gas vs Gas Storage Hot Water Systems: Which Is Better?

Choosing between instant gas and gas storage hot water depends on your household size, number of bathrooms, shower habits, gas type, available space, budget and whether you prefer continuous flow hot water or a traditional storage tank. Both systems use natural gas or LPG, but they work very differently.

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

Quick Answer: Is Instant Gas or Gas Storage Better?

Instant gas hot water is usually better if you want continuous flow gas hot water, have suitable natural gas or LPG supply, and the selected flow rate in L/min matches your household demand.

Gas storage hot water is usually better if you want a traditional tank-style gas replacement, your current gas storage setup works well, and the selected tank capacity and recovery rate suit your home.

As a general guide:

• Choose an instant gas hot water system if you want a compact wall-mounted external unit and continuous flow hot water.

• Choose a gas hot water system if your home already has gas storage and you want a familiar tank-style replacement.

• Choose instant gas by flow rate in L/min.

• Choose gas storage by tank capacity and recovery rate.

• Confirm natural gas or LPG before ordering, because gas types are not interchangeable.

• Check gas supply, water pressure, dimensions, connection positions and required valves before buying.

The better option is the one that suits your property. Instant gas is not automatically better for every home, and gas storage is not outdated if it still suits the household and replacement setup.

Instant Gas vs Gas Storage at a Glance

Both options can work well when correctly selected. The right choice depends on your home’s gas setup, hot water demand and available space.

What Is Instant Gas Hot Water?

An instant gas hot water system, also called continuous flow gas hot water, heats water only when a hot water tap is turned on. It does not keep a large tank of hot water stored.

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

Common instant gas flow rates include:

• 16 L/min

• 20 L/min

• 26 L/min

Instant gas may suit homes where:

• Natural gas or LPG is available

• Continuous flow hot water is preferred

• A compact external wall-mounted unit is suitable

• A large storage tank is not ideal

• The selected flow rate matches household demand

• Gas supply and water pressure are suitable

• The correct natural gas or LPG model is chosen

Instant gas can be a strong option for many homes, but it must be sized properly.

What Is Gas Storage Hot Water?

A gas storage hot water system heats water using natural gas or LPG and stores it in a tank ready for use.

Gas storage systems are sized by tank capacity and recovery rate.

Gas storage may suit homes where:

• The current system is gas storage

• A traditional tank-style replacement is preferred

• Natural gas or LPG is already available

• The selected tank size suits household demand

• Recovery rate is suitable

• The existing location works

• A like-for-like gas replacement is preferred

Gas storage is often practical when the old gas storage system has performed well and the household wants a simpler replacement pathway.

Main Difference Between Instant Gas and Gas Storage

The main difference is whether hot water is stored or heated on demand.

Instant gas heats water as it passes through the system. Gas storage heats water and keeps it in a tank.

This means instant gas and gas storage cannot be compared by litres alone. One is measured by flow rate, the other by tank size and recovery.

Instant Gas Hot Water Pros

Instant gas can be a good choice when the home has suitable gas supply and the unit is sized correctly.

Benefits may include:

• Continuous flow hot water where correctly sized

• Compact wall-mounted design

• No large storage tank

• Common choice for homes wanting gas continuous flow

• Available in different flow rates

• Suitable for many family homes where gas supply supports it

• Can suit one-bathroom and two-bathroom homes when selected properly

Instant gas is especially worth comparing if the current gas system is old, space is limited, or continuous flow hot water is preferred.

Instant Gas Hot Water Cons

Instant gas is not the best option for every property.

Potential drawbacks include:

• Natural gas and LPG models are not interchangeable

• Flow rate must match household demand

• Gas supply must suit the selected unit

• Water pressure and flow can affect performance

• A low-flow unit may not suit larger homes

• Changing from gas storage to instant gas may involve extra work

• Controller compatibility needs to be checked

• External location requirements must be suitable

The main mistake is choosing a smaller instant gas system by price without checking bathroom count, shower habits and peak demand.

Gas Storage Hot Water Pros

Gas storage can be a practical and familiar option, especially for like-for-like replacement.

Benefits may include:

• Traditional tank-style gas hot water

• Practical when replacing existing gas storage

• Uses natural gas or LPG where already available

• Tank capacity can be matched to household size

• Recovery rate can support regular use when suitable

• Often easier to compare where the current gas storage system worked well

• Can suit homes where instant gas changeover is not preferred

Gas storage can be a good choice when the existing tank setup is suitable and the household prefers a straightforward replacement.

Gas Storage Hot Water Cons

Gas storage may not suit every buyer or property.

Potential drawbacks include:

• Stores a set amount of hot water

• Can run out if undersized

• Tank takes up space

• Tank capacity and recovery both need to suit demand

• Natural gas and LPG must be confirmed

• Not as compact as many wall-mounted instant gas units

• May not be preferred where continuous flow is wanted

• Replacement still requires licensed gas and plumbing work

The main mistake is choosing gas storage by tank size alone without considering recovery rate and household peak use.

Which Is Better for Small Homes?

Small homes may suit either instant gas or gas storage depending on the existing setup.

Instant gas may suit a small home if:

• Natural gas or LPG is already available

• A compact wall-mounted system is preferred

• One bathroom is used most of the time

• Hot water demand is moderate

• A 16 L/min or 20 L/min system suits usage

Gas storage may suit a small home if:

• The current system is gas storage

• A tank-style replacement is preferred

• The selected tank size is not oversized

• The existing location works well

• Recovery rate suits daily demand

For small homes, do not choose the cheapest system automatically. The system still needs to match shower habits, kitchen use, laundry use and gas type.

Which Is Better for Families?

Family homes need careful sizing because hot water demand can be high.

Instant gas may suit families if:

• Natural gas or LPG is available

• A 20 L/min or 26 L/min system suits demand

• Continuous flow hot water is preferred

• Multiple showers happen close together

• Gas supply and water pressure are suitable

Gas storage may suit families if:

• The current gas storage system works well

• A larger tank or stronger recovery rate suits demand

• A traditional storage replacement is preferred

• The home has space for a tank

• Natural gas or LPG is confirmed

For families, sizing is more important than system type. A correctly sized system matters more than choosing instant or storage by name alone.

Which Is Better for One Bathroom?

A one-bathroom home may suit instant gas or gas storage.

Instant gas may suit if:

• The home has lower to moderate demand

• A 16 L/min or 20 L/min model suits use

• Natural gas or LPG is available

• A compact external unit is preferred

Gas storage may suit if:

• The home already has gas storage

• The selected tank capacity suits the household

• Recovery rate is suitable

• A like-for-like replacement is preferred

One bathroom does not always mean low hot water use. A one-bathroom family home may still need a capable gas system.

Which Is Better for Two Bathrooms?

Two-bathroom homes need more careful hot water sizing because demand can overlap.

Instant gas may suit two bathrooms if:

• A 20 L/min or 26 L/min system suits peak demand

• Natural gas or LPG is available

• Gas supply can support the selected unit

• Water pressure and flow are suitable

• Continuous flow hot water is preferred

Gas storage may suit two bathrooms if:

• Tank capacity is suitable

• Recovery rate is strong enough

• The current gas storage setup works well

• A larger tank can fit

• A traditional gas tank replacement is preferred

For many two-bathroom homes, 26 L/min instant gas is commonly compared, but gas supply and water pressure still need to be checked.

16L vs 20L vs 26L Instant Gas

Instant gas hot water systems are commonly compared by flow rate.

A 16 L/min system may be enough for some small homes, but it may not suit a two-bathroom family property. A 26 L/min system may suit higher-demand homes, but it still needs suitable gas supply.

Gas Storage Tank Size and Recovery Rate

Gas storage is different from instant gas because it stores hot water in a tank.

Two things matter:

• Tank capacity

• Recovery rate

Tank capacity tells you how much hot water the system stores.

Recovery rate helps indicate how quickly the system can heat more water after use.

Recovery rate matters when:

• Several people shower close together

• The home has a bath

• The household has higher evening or morning demand

• The property is a rental

• The current tank runs out often

• The home has multiple occupants

Do not choose gas storage by tank size alone. Recovery rate is part of the comparison.

Natural Gas vs LPG

Before choosing instant gas or gas storage, confirm whether the property uses natural gas or LPG.

Natural gas and LPG systems are not interchangeable.

Before ordering, check:

• Current hot water unit label

• Gas meter

• LPG bottle setup

• Existing appliance details

• Product listing gas type

• Licensed gas fitter advice if unsure

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

Gas Supply Requirements

Gas supply matters for both instant gas and gas storage, but it is especially important when choosing a higher-flow instant gas system.

Gas supply suitability can be affected by:

• Existing gas line sizing

• Distance from the gas meter or LPG bottles

• Other gas appliances

• Regulator setup

• Natural gas or LPG setup

• System location

• Product requirements

A 26 L/min instant gas unit may need more gas supply capacity than a smaller unit. A licensed gas fitter should confirm suitability before connection work.

Water Pressure and Flow

Instant gas performance can depend on water pressure and flow. A higher-flow unit still needs the property’s water supply and plumbing setup to support demand.

Before choosing instant gas, check:

• Existing water pressure

• Shower flow rates

• Number of hot water outlets

• Whether multiple fixtures run together

• Pipework condition

• Product specifications

If the home has low water pressure or flow issues, changing the hot water unit may not solve the underlying problem.

Controller Compatibility

Some instant gas hot water systems support temperature controllers. Controllers can be useful, but compatibility is model-specific.

Before choosing instant gas, check:

• Whether controllers are supported

• Which controllers are compatible

• Whether existing controllers can be reused

• Whether controllers are included or separate

• Whether extra wiring may be required

• How many controllers can be connected

Do not assume an old controller will work with a new instant gas unit.

Space and Location Requirements

Instant gas and gas storage have different space requirements.

Instant gas usually needs:

• External wall space

• Suitable clearances

• Gas and water connection access

• Power connection where required

• Controller wiring where relevant

• Access for licensed tradespeople

Gas storage usually needs:

• Tank footprint

• Suitable base or platform

• Gas and water connection access

• Safe location for the system type

• Drainage considerations

• Access for delivery and replacement

A system with the right size can still be unsuitable if it does not fit the available location.

Replacing Existing Gas Storage With Instant Gas

Many homeowners compare instant gas when replacing an old gas storage system.

This may be worth considering if:

• Continuous flow hot water is preferred

• A large storage tank is no longer ideal

• External wall space is available

• Natural gas or LPG is confirmed

• The selected flow rate suits the home

• Gas supply can support the unit

• Licensed tradespeople confirm suitability

Changing from gas storage to instant gas may involve different connection requirements. It should not be assumed to be a simple swap.

Replacing Existing Instant Gas With Gas Storage

Some homes may prefer to return to gas storage or keep a tank-style system.

This may be worth considering if:

• A storage tank better suits the household

• The existing instant gas system has not suited use

• The home has space for a gas storage tank

• Natural gas or LPG is available

• Tank capacity and recovery rate match demand

• A traditional system is preferred

Changing from instant gas to storage should be checked by licensed tradespeople because connection and location requirements may differ.

Like-for-Like Gas Replacement

A like-for-like replacement may be practical if the current system has worked well.

Like-for-like replacement may suit when:

• The current system meets household demand

• The household size has not changed

• Bathroom count has not changed

• The same energy source is still preferred

• The location still works

• The selected product specifications match the home

If the old system struggled, do not replace it with the same size automatically. Compare a better-suited option first.

Should You Change From Gas Storage to Instant Gas?

Changing from gas storage to instant gas may be worth comparing if the household wants continuous flow gas hot water and the property suits it.

Instant gas may be worth considering if:

• The existing gas storage tank is old

• The home wants a compact wall-mounted unit

• The household wants continuous flow hot water

• Natural gas or LPG is available

• A suitable external wall location exists

• The selected flow rate suits the household

• Gas supply and water pressure are suitable

Gas storage may still be better if:

• The current tank setup works well

• A straightforward replacement is preferred

• The home does not suit instant gas location requirements

• The gas supply may not support a larger instant system

• A tank-style system is preferred

Should You Stay With Gas Storage?

Staying with gas storage may be the right choice if the existing setup suits the home.

Gas storage may be practical if:

• The current gas storage system has performed well

• Tank capacity suits daily use

• Recovery rate is suitable

• The system location works

• Natural gas or LPG is confirmed

• A traditional gas replacement is preferred

However, if space is tight or continuous flow hot water is preferred, instant gas may be worth comparing.

Should You Choose Instant Gas Instead?

Instant gas may be the better option if the property and household demand suit it.

Instant gas may suit when:

• Continuous flow hot water is preferred

• A compact external wall-mounted system is wanted

• Natural gas or LPG is available

• Flow rate matches household demand

• Gas supply can support the selected system

• Water pressure and flow are suitable

• The household has higher peak demand

Instant gas should not be chosen only because it sounds modern. It needs to suit the home.

Which Is Cheaper: Instant Gas or Gas Storage?

The cheaper option depends on the product, size, brand, gas type, supply-only price, accessories and installation requirements.

When comparing price, check:

• Product cost

• Flow rate if instant gas

• Tank capacity if gas storage

• Recovery rate if gas storage

• Natural gas or LPG model

• Brand

• Warranty information

• Required valves and fittings

• Controller accessories

• Delivery requirements

• Plumbing and gas fitting requirements

• Whether changing system type adds extra work

Hot Water Outlet sells supply-only hot water systems and accessories online. Supply-only pricing usually does not include installation, gas fitting, plumbing, disposal, valves, fittings, pipework changes or compliance upgrades unless clearly stated.

Which Has Lower Running Costs?

Running costs depend on the gas type, household use, system size, gas tariff, product design and how well the system suits the home.

As a general guide:

• Instant gas heats water on demand.

• Gas storage keeps heated water stored in a tank.

• Gas storage recovery rate and tank size affect performance.

• Instant gas flow rate affects peak use comfort.

• Oversized or undersized systems can reduce value.

• Incorrect gas type or poor sizing can create problems.

Do not choose by running cost claims alone. Correct sizing and property suitability are essential.

Instant Gas vs Gas Storage for Renovations

Renovations are a good time to compare system types because bathroom count, fixture demand and system location may change.

Instant gas may suit a renovation if:

• A wall-mounted external unit suits the new layout

• Natural gas or LPG is available

• A second bathroom is being added

• Continuous flow hot water is preferred

• Gas supply can support the chosen flow rate

Gas storage may suit a renovation if:

• The home already uses gas storage

• A tank location is already available

• Tank capacity and recovery suit the finished layout

• A traditional gas system is preferred

• The replacement path is simpler

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

Instant Gas vs Gas Storage for Rental Properties

Rental properties should be sized for likely tenant demand.

Instant gas may suit rentals if:

• Natural gas or LPG is available

• Flow rate suits the number of bedrooms and bathrooms

• A compact wall-mounted system is preferred

• The gas supply and water pressure are suitable

Gas storage may suit rentals if:

• The rental already has gas storage

• Tank capacity and recovery suit likely occupants

• A like-for-like replacement is practical

• The current setup has been reliable

Avoid undersizing rental hot water just to reduce upfront cost. A system that cannot keep up may create tenant complaints.

Valves, Fittings and Accessories

Instant gas and gas storage replacements 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

• Fittings

• Controller accessories

• 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 Comparing Instant Gas and Gas Storage

Comparing L/min to Litres

Instant gas is sized by L/min. Gas storage is sized by tank capacity and recovery rate. These are different measurements.

Choosing the Wrong Gas Type

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

Choosing Too Low a Flow Rate

A low-flow instant gas unit may not suit families, two bathrooms or overlapping hot water use.

Ignoring Recovery Rate

Gas storage performance depends on more than tank capacity. Recovery rate matters too.

Assuming Instant Gas Is Always Better

Instant gas can be excellent in the right home, but it is not always the simplest or most suitable replacement.

Assuming Gas Storage Is Always Outdated

Gas storage can still suit homes where a tank-style system works well.

Forgetting Gas Supply

Larger instant gas systems need suitable gas supply. This should be checked before ordering.

Forgetting Valves and Fittings

The main unit may not be the full order. Accessories may also be needed.

Instant Gas vs Gas Storage Buyer Checklist

Before choosing between instant gas and gas storage, check:

• Current gas hot water system type

• Current brand and model

• Current tank capacity or flow rate

• Whether the current system keeps up

• Natural gas or LPG

• Number of people in the home

• Number of bathrooms

• Number of showers per day

• Whether two outlets may run together

• Shower habits

• Bath use

• Kitchen hot water use

• Laundry use

• Desired system type

• Flow rate in L/min if instant gas

• Tank capacity if gas storage

• Recovery rate if gas storage

• Gas supply suitability

• Water pressure and flow

• Controller requirements if instant gas

• Product dimensions

• Connection positions

• Required valves and fittings

• Delivery access

• Warranty information

• Product specifications

Compare Instant Gas and Gas Storage Hot Water Online

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

Start with:

• Instant Gas Hot Water Systems

• Gas Hot Water Systems

• Hot Water Systems

• Valves, Pipework and Fittings

If gas is not available or not preferred, compare electric hot water systems and heat pump hot water systems.

FAQs About Instant Gas vs Gas Storage Hot Water

Is instant gas better than gas storage?

Instant gas may be better if continuous flow hot water is preferred and the home has suitable gas supply, water pressure and flow demand. Gas storage may be better if the current tank setup works well and a straightforward replacement is preferred.

Is gas storage better than instant gas?

Gas storage may be better where a traditional tank-style replacement suits the property, tank capacity and recovery are suitable, and the existing gas storage setup has been reliable.

Does instant gas hot water run out?

Instant gas does not run out of stored hot water because it does not use a storage tank. However, the flow rate still needs to match household demand.

Can gas storage hot water run out?

Yes. Gas storage can run out of stored hot water if the tank is undersized or demand is high. Recovery rate affects how quickly more hot water is heated.

Is 16L instant gas enough?

A 16 L/min instant gas system may suit smaller one-bathroom homes with lower demand. It may not suit larger families, two bathrooms or overlapping hot water use.

Is 20L instant gas enough?

A 20 L/min instant gas system may suit moderate household demand. Suitability depends on bathroom count, shower habits, gas type and whether multiple outlets run together.

Is 26L instant gas enough?

A 26 L/min instant gas system is commonly compared for family homes, two-bathroom properties and higher peak demand. Gas supply and water pressure still need to be checked.

Can I replace gas storage with instant gas?

Some homes can replace gas storage with instant gas, but suitability depends on gas type, gas supply, water pressure, wall location, flow rate and connection requirements. Licensed tradespeople should assess the setup.

Are natural gas and LPG systems the same?

No. Natural gas and LPG systems are different and are not interchangeable. Always choose the model that matches the property’s gas type.

Can I install instant gas or gas storage myself?

No. Gas hot water systems involve gas and plumbing 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 Gas Hot Water System

The right choice between instant gas and gas storage depends on your household demand, gas type, available space and replacement setup. Instant gas may suit homes wanting continuous flow gas hot water with suitable gas supply. Gas storage may suit homes wanting a traditional tank-style replacement with suitable capacity and recovery.

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