A high electricity bill usually comes from one of four things: more usage than you realise, a tariff or meter change, a seasonal load like heating or cooling, or an electrical fault quietly wasting power. Hot water and air conditioning are the usual culprits. A fault is rarer, but it keeps costing you until it is found.
Most advice on high bills comes from energy retailers, so it stops at "use less". This guide covers the part an electrician sees: how to tell which of the four you have.
What normally makes an electricity bill jump?
Work out which of the four causes you have before you change anything, because the fix for each is completely different. People assume it is usage and start switching things off, when the bill may have moved for a reason unrelated to how much power the house drew.
- More usage. A new appliance, a pool, an electric vehicle, or more people at home.
- Billing and rates. A longer billing period, a rate change, a lower solar feed-in rate, or an estimated read.
- Seasonal load. Heating and cooling are the biggest swings in an Australian home, and they spike then subside.
- An electrical fault. Something is drawing power that should not be. It does not spike and it does not correct itself.
Compare kilowatt hours against the same quarter last year, not the dollar total. Flat kilowatt hours with a higher total means billing.
Which appliances actually use the most electricity?
Hot water and climate control dominate almost every Australian household bill. Standby power is real, but chasing phone chargers while a hot water system runs constantly achieves nothing.
| Load | Why it costs | What actually helps |
|---|---|---|
| Electric hot water | Typically around 3.6 kW, every day of the year | Move it to a controlled load tariff, and have the thermostat checked |
| Heating and cooling | Several kilowatts, running for hours in a heatwave | Widen the temperature range and zone off unused rooms |
| Pool and spa pumps | Moderate draw, but six to eight hours every day | Shorten the run time and check the timer |
| Old halogen lighting | Ten times an LED, and a house can have forty | Convert to LED, an obvious payback |
Our guide to controlled load electricity explains how to check the hot water circuit matches what your bill says.
Did your bill go up without your usage changing?
If the kilowatt hours are flat but the dollar total has risen, the cause is on the billing side. Check these four first.
- The number of days. A 95 day quarter costs more than an 85 day one at identical usage.
- Rate changes. A benefit period can expire and roll you onto a higher rate without the plan changing.
- Estimated reads. If the meter was not read, the bill is a guess. A high estimate is corrected later, but one quarter looks alarming.
- Solar feed-in. A reduced feed-in rate raises your net bill even though consumption has not changed.
A meter change moves the goalposts too. If a meter swap took hot water off a controlled load rate onto a general rate, the same hot water costs more. Raise that with your retailer, and with a smart metering electrician if the wiring is in doubt.
Think something is drawing power it should not be?
DM Electrical tests for earth leakage, failed hot water elements and thermostats, and circuits drawing load with everything switched off. Based in Brookvale, available 24/7 across Sydney.
When is a high bill actually an electrical fault?
A fault costs you continuously rather than in a spike, so the tell is a bill that stays high every quarter regardless of the weather. These are the ones we get called out to find.
- A failed hot water thermostat or element. The most common cause we see. A healthy storage unit heats, reaches temperature and switches off. With a failed thermostat the element stays on, and the water still gets hot, so nothing looks wrong.
- Earth leakage. Damaged insulation, water in an outdoor circuit, or a failing appliance lets current leak to earth, and you pay for current that does no work. Bad leakage trips the safety switch, which our guide to an RCD that keeps tripping covers. Leakage below the trip threshold gives you no warning at all, and only shows up on the bill.
- A controlled load circuit on the wrong tariff. The hot water is wired as though it is on an off peak rate, but the metering has it on the general rate.
- A failed element in an oven, cooktop or floor heating. Less common, but the mechanism is the same as a hot water element.
- A faulty or misconfigured meter. Rare, and worth ruling in last, once the installation tests clean.
How do you find what is using the power?
You can narrow it down yourself in about fifteen minutes. The test relies on a house with everything off drawing almost nothing.
- Switch off every appliance you can, including standby devices. Leave the fridge running and allow for it.
- Watch the meter. A digital meter shows current usage, an older disc meter shows it by how fast the disc turns.
- If it still records meaningful usage, something is drawing power that should not be. Check hot water first.
- Turn circuits off at the switchboard one at a time. The one that makes the reading drop is the one to investigate.
With a smart meter, your retailer's app shows usage by the hour. A flat line of constant usage overnight points to a fault, where a pattern that rises and falls through the evening is ordinary use.
What can an electrician fix, and what belongs to your retailer?
An electrician fixes the installation and the retailer sets the price, so it pays to know which side of that line your problem sits on.
An electrician can test for earth leakage, replace a failed hot water element or thermostat, confirm a residential circuit is on the tariff it should be, convert halogen lighting to LED, and arrange metering work. If your switchboard is old enough that circuits are not clearly separated, a switchboard upgrade makes fault finding much quicker.
What an electrician cannot do is change your rates, move you to another plan, or correct an estimated read. Once the installation tests clean, you can go back to your retailer knowing the problem is on their side.
Frequently asked questions
Can an electrician tell me why my electricity bill is high?
An electrician can rule the electrical causes in or out, which is the part a retailer cannot help with. That means testing for earth leakage, checking whether a hot water thermostat has failed and is heating around the clock, and measuring what circuits draw. If the installation tests clean, the cause is usage or billing.
Does a faulty appliance make your electricity bill go up?
Yes, and a failed hot water system is the clearest example. A storage heater with a failed thermostat keeps its element on instead of cycling off at temperature, so a unit that should heat for a few hours a day runs continuously. Nothing looks wrong, because the water still gets hot.
Why did my bill go up when my usage stayed the same?
Check the billing period and the rates before you look at your appliances. A quarter can cover more days than the one before, your retailer may have changed its rates, a feed-in rate may have dropped, or the bill may be an estimated read.
Which appliance uses the most electricity in an Australian home?
For most homes it is hot water, followed by heating and cooling. An electric storage hot water system typically draws around 3.6 kW while its element is on, and it runs every day of the year. Air conditioning draws more, but only in season.
The bottom line
Start with the kilowatt hours rather than the dollars. If usage is flat, the answer is in the billing period, the rates, or an estimated read, which is a retailer conversation. If usage is genuinely up and it is not the season, work through hot water, climate control and pool pumps, then test for anything drawing power with the house switched off. A constant overnight draw will keep costing you every quarter until someone traces it. If your bill has climbed and you cannot account for it, get in touch and we will test the installation.