Should I Replace My Hot Water System With the Same Type?

Your hot water system has failed, started leaking or become increasingly unreliable.

The simplest solution appears obvious: remove the old unit and replace it with a newer version of the same thing.

If you currently have electric storage, install another electric storage system. If you have gas, stay with gas. If an old solar hot water system has reached the end of its life, replace it with another solar system.

In many homes, a like-for-like replacement is a practical and sensible choice. It can reduce installation complexity, restore hot water quickly and make use of the plumbing and energy connections already available.

However, replacing the existing system with the same type is not automatically the best decision.

The old system may have been installed when the household, property and energy market looked very different. Before repeating that decision, it is worth considering whether the same type of system still suits the way your home operates today.

What Is a Like-for-Like Hot Water System Replacement?

A like-for-like replacement generally means installing a new hot water system that uses the same energy source and operates in a similar way to the old unit.

Examples include:

• Replacing an electric storage tank with another electric storage tank
• Replacing a gas storage system with another gas storage system
• Replacing a continuous-flow gas unit with another continuous-flow unit
• Replacing an existing heat pump with a newer heat pump system
• Replacing an old solar hot water system with another solar system

The new system does not necessarily need to be the same brand or capacity. The replacement may still be adjusted to better suit the household.

The important distinction is that the home is retaining the same general hot water technology rather than changing to a different energy source or operating method.

Why Is Like-for-Like Replacement Often the Simplest Option?

Changing hot water system types can require more than replacing the unit itself.

A like-for-like replacement may already have access to:

• The required electrical circuit
• An appropriate gas supply
• Existing hot and cold-water pipework
• Suitable drainage
• An established installation location
• A concrete base or mounting position

Reusing suitable infrastructure can reduce the amount of plumbing, electrical or gas work required.

This can be particularly important when a system fails unexpectedly and the household needs hot water restored quickly.

However, existing infrastructure should only be reused when it remains suitable and compliant. Old valves, damaged pipework, an inadequate base or an unsuitable installation position may still need to be addressed.

When Does Replacing the System With the Same Type Make Sense?

A like-for-like replacement may be the right choice when:

• The existing system has generally provided enough hot water
• The household has not changed significantly
• The system has been reasonably affordable to operate
• The existing energy connection will remain in use
• The installation position is still suitable
• The homeowner wants a straightforward replacement
• Changing systems would require substantial additional work
• The replacement is urgent

There is no benefit in making a replacement unnecessarily complicated when the existing system type still suits the home.

The replacement should still be sized correctly and the condition of the surrounding installation should be checked.

When Should You Consider Changing Hot Water System Types?

A system failure creates an opportunity to reconsider a decision that may not arise again for many years.

Changing system types may be worth investigating when:

• The household regularly runs out of hot water
• The existing system appears expensive to operate
• Rooftop solar has been installed since the old system was selected
• The household wants to reduce its reliance on gas
• The property is being renovated
• The current unit is poorly positioned
• The number of people in the household has changed
• The existing technology no longer suits the homeowner’s priorities
• Major work is already required to install a replacement

The answer does not automatically need to be a heat pump, gas system, solar system or conventional electric tank.

The purpose of comparing alternatives is to determine whether another option would genuinely suit the property better.

Has Your Household Changed Since the Old System Was Installed?

Hot water systems can remain in service for many years. During that time, the household using the system may change considerably.

A system originally selected for two people may now serve a family with several children. Alternatively, a large family home may now contain only one or two occupants.

Changes that can affect hot water requirements include:

• Children becoming teenagers
• Adult children leaving home
• A partner moving into the property
• Older relatives joining the household
• More people working from home
• A second bathroom being added
• A granny flat being constructed
• The property becoming a rental

Replacing the system with exactly the same capacity may reproduce an existing shortage or leave the home paying for more storage than it needs.

Did the Old System Actually Perform Well?

A system lasting for many years does not necessarily mean it was well suited to the home.

Before replacing it with the same type, consider how it performed.

Did the household experience:

• Hot water running out during peak periods?
• Long waits for the water to reheat?
• Inconsistent water temperatures?
• Higher-than-expected energy bills?
• Poor performance during winter?
• Frequent repairs?
• Excessive noise?
• Long delays before hot water reached the tap?

Some of these problems may have been caused by a fault rather than the system type. Others may indicate that the capacity, recovery rate, location or technology was not right for the property.

The underlying problem should be identified before the same arrangement is installed again.

Does the Home Now Have Rooftop Solar?

Many hot water systems were installed before rooftop solar was added to the home.

If the property now generates electricity during the day, it may be worth considering how the new hot water system could work with that generation.

This does not automatically mean one particular system must be installed.

The decision may involve:

• The amount of surplus solar electricity normally available
• When the hot water system operates
• Whether the system can be placed on a timer
• The household’s electricity tariff
• Whether the home has a battery
• Whether a battery is planned
• How much hot water the household uses

An electric storage or heat pump system may be able to operate during periods of stronger solar production, but the correct arrangement depends on the property’s electrical setup and household usage.

Are You Planning to Remove Gas From the Property?

A failed gas hot water system can force homeowners to decide whether they still want gas connected to the property.

The answer may depend on whether gas is also used for:

• Cooking
• Room heating
• A pool or spa
• An outdoor kitchen
• Other appliances

If hot water is the final remaining gas appliance, replacing it with another gas system may mean retaining the gas connection for that appliance alone.

Some homeowners may consider changing to an electrical option. Others may prefer to retain gas because the infrastructure is already present and the existing system has suited the household.

The complete cost and practical impact of either decision should be considered. Changing from gas may require electrical and plumbing work, while staying with gas may preserve ongoing gas supply charges and maintenance requirements.

Would Changing Systems Require Electrical Upgrades?

Changing from gas or solar hot water to an electrical system may require an electrician to assess the property.

Depending on the proposed system and existing installation, the work may involve:

• A new electrical circuit
• Changes at the switchboard
• A suitable isolating switch
• Controlled-load or tariff changes
• A timer or energy-management control
• Coordination between the plumber and electrician

These costs should be included when comparing a system change with a like-for-like replacement.

A different system may still be worthwhile, but comparing only the purchase price of the units will not reveal the complete installation cost.

Would Changing Systems Require Gas Work?

Moving to gas hot water may require confirmation that the property has an adequate gas supply.

The existing gas pipework must be suitable for the demand of the proposed unit and any other gas appliances operating at the property.

Changing away from gas may also require the redundant service to be safely disconnected or capped.

This is particularly relevant during renovations where homeowners are replacing gas cooktops, heating or hot water as part of a broader move towards an all-electric home.

Can the New System Remain in the Same Position?

Different hot water technologies have different installation requirements.

A position suitable for an old electric tank may not necessarily suit a heat pump, continuous-flow unit or replacement solar system.

The installer may need to consider:

• Available space
• Access for installation
• Future servicing access
• Drainage
• Ventilation and airflow
• Clearance from windows and doors
• Noise near bedrooms or neighbouring properties
• Exposure to weather or physical damage
• The distance from bathrooms and kitchens

Relocating a system can improve the installation, but it can also add pipework, labour and supporting work to the quote.

Are You Replacing the System During a Renovation?

A renovation can be the ideal time to reconsider the hot water system because plumbers and electricians may already be altering the property’s services.

Planned work could include:

• Adding a bathroom
• Moving the kitchen or laundry
• Removing gas appliances
• Upgrading the switchboard
• Installing rooftop solar
• Relocating external plumbing
• Creating a new plant or service area

Replacing the system without considering these changes could result in the new unit being poorly located or incorrectly sized once the renovation is complete.

The hot water decision should form part of the broader renovation plan rather than being treated as an isolated appliance replacement.

How Urgent Is the Replacement?

There is an important difference between planning for the replacement of an ageing system and dealing with a tank that has failed completely.

When the home has no hot water, the options may be affected by:

• Which systems are currently available
• How quickly the required trades can attend
• Whether additional electrical or gas work is needed
• Whether the proposed system requires relocation
• How long the household can reasonably remain without hot water

A straightforward replacement can sometimes be completed more quickly than a change of technology.

That does not make it the wrong choice. It simply means the urgency of the situation is one of the factors the homeowner must weigh against potential longer-term benefits.

Should You Change Systems Just to Access a Rebate?

A discount or rebate can reduce the upfront price of an eligible system, but it should not be the only reason the system is selected.

The homeowner should still consider:

• Whether the system is correctly sized
• The quality and support behind the unit
• The complete installation requirements
• Likely household usage
• Noise and location
• Warranty arrangements
• Parts and servicing availability
• The expected operating cost

A heavily discounted system is not good value when it is unsuitable for the property or does not provide reliable hot water.

The product, installation and after-sales support should be evaluated together.

Questions to Ask Before Choosing Like-for-Like Replacement

Before accepting a quote for the same type of system, ask:

• Did the old system provide enough hot water?
• Is the proposed capacity suitable for the current household?
• What alternatives are practical at this property?
• Would changing system types require additional work?
• Does the home’s rooftop solar affect the options?
• Will gas remain connected for other appliances?
• Are the existing valves and pipework suitable?
• Can the new system remain in the same position?
• What is included in the replacement quote?
• What are the expected advantages and compromises of each option?

A good recommendation should explain both why a particular system is suitable and why the available alternatives may be less appropriate.

Like-for-Like Versus Changing Systems: A Simple Starting Point

A like-for-like replacement may make sense when:

• The existing system has performed well
• The household’s needs remain similar
• The existing services and location are suitable
• The system needs to be replaced urgently
• The homeowner values a straightforward installation

Changing system types may be worth investigating when:

• The old system never met the household’s needs
• Energy usage is a major concern
• Rooftop solar has changed the home’s energy setup
• The homeowner wants to move away from gas
• A renovation is already changing the property’s services
• The current system requires significant work regardless

Neither approach is automatically right or wrong.

The correct choice depends on the home, the household and the complete cost of installing and operating the replacement.

Compare the Options Before Repeating the Old Decision

Replacing a failed hot water system with the same type can be practical, affordable and entirely appropriate.

However, the decision should be deliberate rather than automatic.

Consider whether the old system provided enough hot water, whether the household has changed, whether rooftop solar or renovation plans affect the options and what additional work would be required to change technologies.

RJT Plumbing & Gas can assess your existing hot water system and explain the practical replacement options available for your property.

Sometimes the right answer is a straightforward like-for-like installation. In another home, changing the size, energy source, system type or location may provide a better result.

Use the RJT hot water system calculator to begin comparing your options, or contact RJT Plumbing & Gas for hot water repairs and replacements across North Lakes, Mango Hill, Griffin, Kallangur, Murrumba Downs and surrounding Moreton Bay suburbs.