8 Ways To Optimise Your QLD Hot Water System & Cut Power Bills

Did you know your hot water system is one of the biggest power consumers in your entire home? In Queensland right now, that matters more than it has in years. Hot water accounts for around a quarter of the average household’s electricity use, translating to somewhere between $375 and $450 a year – just to keep the shower warm!

Let’s stack that up against the cost-of-living horror we’re currently going through:

• The RBA has now hiked the cash rate three times this year
• The Middle East conflict is driving fuel prices sharply higher
• Inflation just keeps growing and growing
• SE Queensland households absorbed electricity price rises of up to 3.7% from July 2025, following a 19.9% spike in a single year before that.

It’s no wonder the power bill has become one of the most talked-about topics at the kitchen table across Brisbane.

Is there any good news at all?

YES! There are things you can do RIGHT NOW to reduce what your hot water costs you – and some of them cost nothing at all.

We’ve got 8 absolute gems:

1. Get on the right tariff

This is the single biggest lever most Brisbane households aren’t pulling – and it costs nothing to switch.

Ergon Energy and Energex both offer economy tariffs specifically designed for hot water systems – and the savings are real.

Tariff 33 is the most commonly used economy tariff for hot water, available for:

• Electric hot water system tanks holding 125 litres or more
• Heat pump systems holding 270 litres or more
• Solar hot water systems holding 160 litres or more.

Power is available for a minimum of 16 hours per day at a current rate of $0.19135 per kWh – cheaper than the standard daytime rate.

Tariff 31 suits larger tanks of 250 litres or more and offers a rate of $0.18118 per kWh with a minimum of 8 hours supply per day.

To connect, you just need a licensed electrician to assess your site and engage your retailer. Your system needs to be hardwired on a dedicated circuit.

If you’re not sure whether you’re already on an economy tariff, check your power bill for references to Tariff 31 or Tariff 33 – if they’re not there, you’re probably paying more than you need to!

2. Right-size your system

It’s pretty simple:

• An oversized tank heats more water than you use, which means you’re paying to maintain the temperature of water that sits unused.
• An undersized system runs harder and may rely on an electric booster more frequently than it should.

In other words, neither is efficient.

As a general guide:

• A 2-person household typically needs 125-160 litres of electric storage capacity.
• A family of four is looking at 250-315 litres.

Getting this right – particularly when considering hot water system installation for a new property or hot water system replacement after a failure – makes a meaningful difference to ongoing running costs.

Talk to a licensed plumber before you commit to a size.

3. Set your thermostat to 60°C

Australian standards require hot water storage at a minimum of 60 °C to prevent Legionella bacteria from forming, but running hotter than that simply costs more energy for no benefit.

Get your hot water plumber to check your thermostat and check that it’s at 60°C consistently. It’s a very quick job that can reduce heating costs without affecting your hot water supply at all.

4. Reduce consumption at the fixture

The cheapest hot water is the hot water you don’t use!:

• Cutting your shower time from 8 minutes to 4 – plenty for a lovely soak! – reduces hot water costs by up to 50%.
• Installing a water-efficient showerhead can save a household of 4 up to $150 annually on hot water alone.
• Switching your laundry to cold water – which modern detergents handle perfectly well – removes a significant portion of hot water demand from your daily load.

None of these changes requires a plumber or an electrician. They require a simple decision – and that’s all!

5. Fix leaks without delay

A leaking hot water tap dripping at 60 drops per minute wastes around 9,000 litres of water per year – and costs approximately $100 in wasted heating energy on top of the water bill.

A leak that’s been sitting for months has already cost you. Get it fixed. Today!

6. Insulate your pipes

Heat loss between your tank and your taps is a hidden ongoing cost that most households never think about. Remember: The longer the pipe run, the more heat dissipates before the water reaches you – and the longer you run the tap waiting for hot water to arrive.

Insulating exposed hot water pipes, particularly those running through unheated roof spaces or long external runs, reduces this loss and means hot water arrives faster. It’s inexpensive and pays for itself over time.

7. Position matters

If you’re planning a hot water system installation or replacement, consider placement – very carefully.

The closer the system is to where hot water is used most – bathroom, kitchen, laundry – the shorter the pipe run and the less heat is lost in transit.

For larger homes, this can be a more significant factor than most people realise when comparing hot water system prices across different configurations.

8. Know when your system type is working against you

A standard electric hot water system running on the general tariff is among the most expensive ways to heat water in a Brisbane home.

The alternatives each have their place:

• A gas hot water system offers faster recovery and lower running costs than standard electric, particularly for larger households with high simultaneous demand.
• A solar hot water system uses the Queensland sun to do the heavy lifting, with a gas or electric booster covering the rest – running costs are among the lowest available for storage systems in SEQ.
• A heat pump hot water system extracts heat from ambient air rather than generating it directly, using up to 70% less electricity than a standard electric storage unit. In Queensland’s warm climate, heat pump technology performs particularly well year-round.
• An instant hot water system heats on demand with no storage losses – efficient for smaller households or where hot water demand is spread throughout the day rather than concentrated in peak periods.

If your current system is ageing and your bills are climbing, the running cost difference between an old electric storage unit and a modern heat pump or solar system can justify hot water system replacement on financial grounds alone – before the system fails and the decision gets made for you.

Get the right advice for your home

Every household is different, and the right combination of tariff, system type, and usage habits depends on your specific setup. If you’re not sure where to start, the team at S&J Hot Water Brisbane can help. Our licensed plumbers handle every sort of hot water system Brisbane homeowners rely on – also offering tariff assessments, system sizing, installation and replacement.

Book your obligation-free quote today.