If you've ever squinted at your electricity bill and spotted a line called "controlled load" with a different rate, you're not alone. Thousands of Australians pay for controlled load electricity without understanding what it actually is — or whether it's helping them.
A controlled load tariff is a separate, cheaper electricity rate applied to specific appliances — usually your electric hot water system or underfloor heating. These appliances are wired to a dedicated circuit and only receive power during off-peak hours set by your electricity distributor. In exchange for giving up control of when these appliances run, you pay a lower rate per kilowatt-hour (kWh).
The savings can be meaningful. On many tariffs across Australia, controlled load rates sit between 40% and 60% lower than the general usage rate. That price gap is why controlled load tariffs exist — and why they're worth understanding properly.
How Does Controlled Load Electricity Actually Work?
Your electricity distributor (the company that owns the poles and wires, not your retailer) decides when power flows to your controlled load circuit. They switch it on during periods of low demand — typically overnight — and switch it off during peak periods.
There are generally two types of controlled load in most Australian states:
- Controlled Load 1 (CL1): Power is available for a minimum of 8 hours, usually overnight. This is the most common type for electric hot water systems.
- Controlled Load 2 (CL2): Power is available for a longer window — typically 18 hours or more — but at a slightly higher rate than CL1.
The exact hours vary by distributor. In the Ausgrid network area of NSW, for example, CL1 typically runs from around 10pm to 7am. In Energex's Queensland network, the hours differ again. Your distributor sets the schedule, and your retailer bills you at the controlled load rate for energy used on that circuit.
The appliance on the controlled load circuit doesn't know the difference. Your hot water system heats the tank when power is available, and the stored hot water lasts through the day.
What Appliances Can Go on a Controlled Load Tariff?
Not every appliance qualifies. Controlled load circuits are designed for appliances that can store energy (as heat) and don't need instant, on-demand power. The most common appliances are:
- Electric storage hot water systems (by far the most common)
- Underfloor heating with thermal storage
- Pool pumps (in some distributor areas)
- Slab heating systems
You can't put your fridge, air conditioner, or oven on a controlled load circuit. These appliances need power whenever you use them. The whole point of controlled load is that the distributor chooses the timing, not you.
If you have an instantaneous (continuous flow) hot water system or a gas system, controlled load doesn't apply — those systems heat water on demand rather than storing it in a tank.
How Much Can a Controlled Load Tariff Save You?
Hot water heating accounts for roughly 25% of the average Australian household's electricity use, according to the Australian Government's energy.gov.au resource. Shifting that 25% from a general usage rate to a controlled load rate creates a genuine cost difference.
Here's a simplified example. Say your general usage rate is 30c/kWh and your controlled load rate is 18c/kWh. If your hot water system uses 2,000 kWh per year:
- On general tariff: 2,000 × $0.30 = $600/year
- On controlled load: 2,000 × $0.18 = $360/year
- Annual difference: $240
That's a real saving for doing nothing differently — just having the right circuit and tariff in place. The actual figures depend on your retailer's rates and your distributor's controlled load availability, but the principle holds across most Australian networks.
One thing to watch: controlled load tariffs sometimes have their own daily supply charge. Check your bill for a separate supply charge line under the controlled load section. If the supply charge is high, it can eat into the per-kWh savings.
Is Your Controlled Load Tariff Set Up Correctly?
Here's where it gets interesting. Some households have a controlled load circuit installed but aren't actually being billed on a controlled load tariff. Others are paying a controlled load supply charge for a circuit they no longer use — perhaps because they switched to gas hot water or installed a heat pump on the main circuit.
Check your bill for these signs:
- A separate line item labelled "Controlled Load 1" or "Controlled Load 2" with its own usage (kWh) and rate
- A separate daily supply charge for the controlled load meter
- If you see controlled load charges but you've changed your hot water system, you might be paying for a circuit that's doing nothing
Your meter setup matters too. Controlled load requires either a separate meter or a meter with multiple registers. If your meter was recently upgraded to a smart meter, it's worth confirming your controlled load tariff transferred correctly. Billing errors during meter changeovers aren't rare.
Does Controlled Load Make Sense With Solar?
This is a question more Australians are asking as rooftop solar grows. If you have solar panels, your controlled load hot water system heats water overnight — when your panels produce nothing. You're buying grid electricity at the controlled load rate instead of using free solar energy during the day.
Some households find it makes more sense to move their hot water system off controlled load and onto their main circuit, then use a timer to run it during peak solar generation hours (typically 10am to 2pm). This way, the hot water system uses self-generated solar electricity instead of overnight grid power.
The maths depends on your controlled load rate versus the value of your solar generation. If your feed-in tariff is low (say 5c/kWh) and your controlled load rate is 18c/kWh, diverting solar to heat water saves you 18c/kWh instead of earning 5c/kWh — a net benefit of 13c for every kWh diverted.
Moving off controlled load requires an electrician to rewire the hot water system to your main switchboard circuit. It's not a DIY job, and it typically costs between $200 and $500 depending on your setup. [USER TO CONFIRM: typical electrician cost range for controlled load rewiring]
Frequently Asked Questions
What is a controlled load tariff on my electricity bill?
A controlled load tariff is a discounted electricity rate for appliances wired to a separate circuit. Your distributor controls when power flows to that circuit, usually during off-peak hours overnight. It most commonly applies to electric storage hot water systems.
Can I choose what hours my controlled load runs?
No. Your electricity distributor sets the hours, not your retailer and not you. The hours vary by network area and controlled load type (CL1 or CL2). You trade control over timing for a lower rate.
Should I take my hot water off controlled load if I have solar panels?
Potentially, yes. If your solar feed-in tariff is low, you may save more by running your hot water system during the day on solar power. An electrician can rewire your hot water system to your main circuit, and a timer can schedule heating during peak solar hours.
How do I know if my controlled load tariff is set up correctly?
Check your electricity bill for a separate controlled load line item showing usage in kWh and a rate. If you see a controlled load supply charge but zero usage, or if you've changed your hot water system type, your tariff setup may need updating. Contact your retailer to review it.
Is controlled load the same as off-peak?
They're related but not identical. Off-peak refers to time-of-use pricing where all your usage during certain hours gets a cheaper rate. Controlled load is a separate circuit where the distributor decides when power flows. You might have both on the same bill.
Take a look at your latest electricity bill. Can you spot a controlled load line? If you can, check whether the rate and usage look right — and if you have solar, it might be time to do the maths on whether that overnight heating is still the cheapest option for your household.
Last updated: June 2025