July 14, 2025

How Long Does It Take to Replace a Hot Water System?

Author:

Proud Plumbing

Waking up to a cold shower is a surefire way to ruin your morning. If your hot water heater is showing signs of failure, your first thought is likely about how to get it fixed as fast as possible. But how fast should you expect?

While there’s no single answer, we can provide a reliable guide based on our extensive experience repairing and replacing hot water systems across Perth. Understanding the timeline helps you plan your day and know when you can expect a lovely hot shower again.

The Average Timeframe for Hot Water System Replacement

For a straightforward, like-for-like replacement, the process typically takes between 2 to 4 hours. This is the most common scenario we encounter.

This standard timeframe assumes we are simply replacing an old hot water system with a new unit of the same type (e.g., electric for electric) and size, in the exact same location. The installation process for this type of job includes disconnecting the old unit, putting the new water heater in place, connecting it to the existing plumbing and power (gas or electricity), and testing it thoroughly.

how long does it take to replace hot water system

Key Factors That Determine How Long the Job Takes

While 2-4 hours is a good baseline, several factors can extend how long it takes to complete the installation. A more complex job might take the better part of a day.

1. Type of Hot Water System: Upgrade or Direct Swap?

The biggest factor influencing the timeline is whether you’re doing a direct swap or changing the type of system. Simply replacing an old system is the quickest option.

However, if you’re switching from an old electric storage tank to a modern, energy-efficient instant gas hot water system, it will almost always take longer. This kind of change is a significant upgrade that can involve new pipework, electrical work, or running a new gas line.

For a detailed comparison of the two most common types of hot water systems, check out our blog on instant vs storage hot water systems.

2. Relocating Your Water Heater

Moving your hot water system from an internal cupboard to an external wall, or from one side of the house to the other, is a major change. This will take longer because it requires our licensed professionals to reroute the cold and hot water lines, as well as the gas or electricity supply. The complexity of this process depends heavily on your home’s layout and construction.

3. Site Accessibility

Where is your current water heater located? A system that’s easily accessible in a garage is much quicker to replace than one tucked away in a tight roof space or a small cupboard. Our technicians need adequate space to work safely and efficiently when they remove the old hot water system and install the new unit.

4. The Specifics of Your New Hot Water Heater

The type of system being installed plays a big role in the timeline.

Electric Storage Water Heaters

These are generally the most straightforward to replace on a like-for-like basis. The process involves replacing the water tank and making the connections. You can learn more about them on our electric storage hot water system page.

Gas Storage Water Heaters

Similar to electric systems in terms of plumbing, but these require a licensed gas fitter to handle the gas connection safely. See our gas storage systems for more info.

Continuous Flow Systems

These tankless water heaters are often quicker to physically mount on the wall, but the installation can take longer if the existing pipework needs to be significantly modified to suit the new system.

Solar Hot Water Systems

These are the most complex hot water systems to install. The installation includes fitting solar panels on the roof, installing a storage tank (which may be on the roof or on the ground), and connecting all the associated water lines and sensors. This process can take a full day or even longer, but the long-term energy savings are significant. Regular maintenance is key, as you can read in our solar hot water maintenance blog.

A Detailed Breakdown of the Installation Process

To give you a clearer picture, here’s a breakdown of what a typical hot water system installation involves from start to finish.

Step 1: Initial Assessment and Safety Check

First, our technician will arrive and assess the site. They will confirm the details of the job, inspect the existing connections, and plan the installation process to ensure everything goes smoothly and safely.

Step 2: Preparing the Area and Draining the Old Unit

Next, we shut off the main water supply to the house, along with the power (gas or electricity) to the old heater. If you have a storage tank system, we will then drain all the water from the tank. How much hot water is in the tank will affect how long this step takes.

Step 3: Disconnecting and Removing the Old Hot Water System

Once the tank is empty and the power is off, the process of replacing the system begins. This includes carefully disconnecting the water lines, gas line, and valves like the tempering valve from the old system. The old unit is then removed from your property.

Step 4: Positioning and Connecting the New Water Heater

The new water heater is then carefully moved into position. Our team takes great care not to damage your property during this step.

Step 5: Valve Installation and Pipework Adjustments

We then connect the hot and cold water lines to the new tank or new system. For gas systems, the gas line is connected. For electric systems, the electrical work is completed. A new tempering valve is often installed to ensure water is delivered to your taps at a safe, controlled temperature.

Step 6: Final Checks, Testing, and Commissioning

With everything connected, the water supply and power are turned back on. The new system is thoroughly tested for any leaks and to ensure its correct operation. We check the temperature and pressure to make sure it can heat water effectively and safely.

Step 7: Cleanup and Disposal

Finally, we make sure the work area is left clean and tidy. We also take the old hot water system away for responsible disposal, so you don’t have to worry about it.

Why You Must Hire a Licensed Professional

Replacing a hot water system is not a DIY job. It involves working with high-pressure water, electricity, and/or natural gas, all of which pose significant risks if not handled correctly.

Safety, Compliance, and Your Home’s Insurance

In Australia, all hot water system installations must be performed by licensed professionals. This ensures the installation meets strict safety standards and building codes. Using an unlicensed person can void your home insurance. Read our blog on why you should hire a licensed gas fitter for more on this topic as it relates to gas systems.

Protecting Your Warranty

The manufacturer’s warranty on your new water heater is only valid if it is installed by a licensed plumber and/or gas fitter. Professional installation gives you peace of mind that your investment is protected.

Planning for Your New Hot Water System

A little planning can make the installation day go much smoother.

Choosing the Right System for a Smooth Installation

If speed is your top priority, replacing your current heater with a similar model is the quickest path to getting your hot shower back. However, a failing system presents a great opportunity to upgrade to a system that might lower your energy bills or be better suited to your household size. For guidance, check out our blog on what size hot water system you need.

Minimising Disruption on Installation Day

You can help the process along by ensuring the area around your hot water system is clear and accessible before our technician arrives.

Get a Reliable Hot Water System Installed Fast

While a standard replacement takes just a few hours, it’s important to account for factors that could make the process take longer. The best way to get an accurate timeframe and a reliable hot water system is to speak with an expert. If you have no hot water at all, it’s a plumbing emergency.

If your hot water heater is on its last legs, or if you need an emergency plumber, you can contact Proud Plumbing and Gas today. We provide expert advice and professional installation across Perth to make sure you have reliable hot water when you need it.

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