Guide to Hot Water System Installation, Replacement, and Maintenance in Australia

A reliable hot water system is essential for any home. Whether you’re installing one for the first time or replacing an old unit, it’s important to choose the right system and ensure it’s installed correctly. This guide explains how hot water systems work, what your options are, and how to maintain them for long-term performance.

Types of Hot Water Systems in Australia

Hot water systems vary in how they’re powered and how they store or heat water. The most common types in Australian homes are gas and electric, followed by solar and heat pump systems.

Gas Hot Water Systems

Gas hot water systems heat water using natural gas or LPG. They’re available in two main types: storage systems and continuous flow (also called instantaneous). Storage systems keep a tank of water heated and ready to use. Continuous flow units heat water only when it’s needed, which can reduce energy waste.

Gas systems tend to be more cost-effective to run than electric ones, especially if the home is already connected to mains gas. Installation must be done by a licensed gas fitter due to safety and compliance requirements.

Electric Water Heaters

Electric water heaters are commonly used in homes without access to natural gas. These systems use a heating element inside a storage tank to warm the water. They’re generally easy to install and have a lower upfront cost, but ongoing electricity costs may be higher compared to gas.

Electric models are available in a range of sizes to suit different household needs. Some are compatible with off-peak tariffs, which can reduce operating costs if scheduled correctly.

Hot Water System Installation

Installing a hot water system is not a DIY job. In Australia, all installations must be carried out by licensed professionals who follow the relevant plumbing and electrical codes. The installation process includes assessing the site, selecting the right unit, and ensuring proper connections.

Installation Steps

1. Disconnect and remove the old unit (if replacing).
2. Prepare the area for the new system (wall mounting or ground placement).
3. Connect water lines, gas or electricity, and any required valves.
4. Test for leaks, ensure correct pressure, and confirm proper operation.
5. Provide a certificate of compliance if gas or electrical work is involved.

Installation usually takes between 2 and 6 hours, depending on the type of system and how accessible the installation site is.

Gas Heater Installation

Gas heater installation must meet Australian safety standards. Licensed gas fitters are required to complete the work. The gas line must be checked for leaks, and ventilation must meet code.

Key Considerations

• Proper flueing or venting is essential to remove combustion gases.
• A tempering valve must be installed to prevent scalding.
• LPG systems must have compliant gas bottle placement and regulators.

After installation, the technician will test the system, check ignition and burner function, and issue a compliance certificate. Never attempt to install a gas heater without a qualified installer.

Water Heater Installation

The term “water heater” includes both gas and electric systems. Choosing the right unit depends on the number of people in the home, available energy sources, and budget.

System Sizing Guidelines

• 1–2 people: 80–125 L storage or small continuous flow
• 3–4 people: 160–250 L storage or medium continuous flow
• 5+ people: 315L+ storage or high-capacity continuous flow

Undersized systems will run out of hot water quickly, while oversized ones waste energy. Always consult a licensed installer before purchasing a new unit.

Gas Hot Water System Replacement

Replacing an old gas hot water system is a common upgrade. Over time, tanks corrode, valves wear out, and heating efficiency declines.

When to Replace

• Water is not heating consistently.
• Visible leaks or rust around the tank
• Pilot light issues in older gas units
• System is more than 10 years old.

During replacement, the old unit is disconnected and removed. The new system is installed in the same location if possible, using existing gas and water lines. Your plumber will make any adjustments to meet current regulations.

Modern gas systems are more efficient than older ones and may include electronic ignition, adjustable temperature settings, and faster recovery times.

Gas Water Heater Replacement vs. New Installation

If you’re replacing an old gas water heater with a similar model, the job is typically straightforward. However, a new installation may involve

• Adding a new gas line connection
• Installing a flue system for indoor units
• Building a concrete slab or wall bracket for mounting

In both cases, the installer must perform safety tests and certify the system before use. Costs vary depending on unit type and installation complexity, but a standard replacement takes less time and labor than a full new install.

Maintenance Tips for Long-Term Performance

Regular maintenance extends the life of your hot water system and helps prevent sudden failures.

What to Check

• Pressure relief valve: Test every 6 months. Replace it if it drips constantly.
• Anode rod (for tanks): Check every 3–5 years. This helps prevent rust inside the tank.
• Water temperature: Should be set to 60°C to kill bacteria but avoid scalding.
• Gas flame: Should burn blue. Yellow or orange flames can signal an issue.

For continuous flow systems, keep the area clear of debris and ensure external units are sheltered but well ventilated.

Final Thoughts

Choosing the right hot water system, having it installed professionally, and maintaining it properly can reduce your energy bills and ensure you always have hot water when you need it.

If your system is over 10 years old or showing signs of wear, it’s time to consider a replacement. A qualified plumber or gas fitter can assess your needs and recommend the best model for your home.

 

Frequently Asked Questions

How long does it take to install a hot water system?

Most installations are completed in 2 to 6 hours.

Can I install a gas water heater myself?

No. In Australia, gas installations must be completed by licensed professionals.

What’s the difference between gas and electric water heaters?

Gas systems have lower running costs, while electric systems are easier to install but may cost more to operate.

How do I know when my system needs to be replaced?

Common signs include water temperature problems, rust, leaks, and unusual noise from the unit.

Are continuous flow systems better than storage tanks?

It depends on usage. Continuous flow units don’t run out of hot water but may struggle with multiple taps at once.