The short answer
What a controlled load tariff actually is
A controlled load is electricity sent to a separately metered circuit in your home, usually electric storage hot water, sometimes slab or underfloor heating or a pool pump, that your network switches on only during set off-peak windows. In return you get the cheapest electricity rate in the house. Here is the part most explainers skip: it is the cheapest power you buy, but you cannot shop for it the way you compare a main plan, and it never shows up in a headline price comparison. Controlled load is not simply a discount. It is a trade: you hand the network control over when the circuit runs, and in exchange you pay a lower rate per kilowatt hour.
Here is the core takeaway in one line: a controlled load is a separately metered off-peak circuit, usually for hot water, that the network runs only in set windows in exchange for the cheapest electricity rate in your house. The common assumption is that controlled load is just a discount you opt into. It is not. The cheap rate exists precisely because you hand the network control over when the appliance runs. Take that control back and the cheap rate disappears with it. That trade is the whole point, and it is also why a solar household now has a genuine reason to think twice.
Reframe the assumption: controlled load is not "a discount on your power". It is a deal where the network borrows your appliance's timing to smooth the evening peak, and pays you back with a lower rate. Cheap power, yes, but on the network's schedule, not yours.
The blind spot
Why most controlled load explainers leave you worse off
Most articles about controlled load do the same three things, and each one quietly misleads readers.
First, they call it a discount and stop there. They tell you the rate is cheap and imply you should always take it. They skip the catch: you give up control of when the circuit runs, and on the cheapest option, Controlled Load 1, you may run short of hot water if your tank is small or your household is large.
Second, they treat controlled load as something you compare like a plan. You cannot. It does not appear in the headline numbers retailers advertise, which quote the general usage rate and the daily supply charge. The controlled load rate sits on a separate line and varies between retailers, so you have to check it deliberately, plan by plan.
Third, they assume overnight off-peak is always smartest. That was true when night was the cheap time. It is no longer automatic. Rooftop solar has made the middle of the day the cheapest power in the country, so for a solar household, heating water at noon can now beat the overnight controlled load rate. A good explainer says so plainly.
How controlled load actually works
Expert analysis: the machinery behind the cheap rate
How a controlled load is metered and switched
A controlled load runs on its own circuit with its own meter, or its own channel on a smart meter, kept separate from your general supply. A device controlled by the network, traditionally a ripple-control relay, more often now a signal to your smart meter, switches that circuit on during the approved off-peak window and off again afterwards. The appliance on it, almost always an electric storage hot water tank, heats up while the circuit is live and then coasts on stored hot water through the day. You see the result as a separate line on your bill, billed at the controlled load rate rather than your general usage rate.
Controlled Load 1 vs Controlled Load 2: hours against rate
There are typically two flavours, and the difference is a trade between hours and price. Controlled Load 1 gets the fewest hours, usually a single overnight block, so the tank has less time to heat. Because that timing is the most valuable to the network, CL1 carries the cheapest rate. Controlled Load 2 gets a longer window that can stretch into daytime hours, so it suits a smaller tank or a household that keeps running out on CL1. The extra hours cost a little more per kilowatt hour. Which option you can have depends on your network and your appliance, not just your preference.
Why the controlled load rate is so cheap
The cheap rate is a load-shifting incentive, not generosity. When you let the network run your hot water only in off-peak windows, you move that demand away from the evening peak, when the grid is most strained and most expensive to supply. Off-peak network charges are far lower, and since network costs are usually the largest slice of a bill, that saving is real. The network passes it back as a discounted rate. The flip side is the one most people miss: the price is low because you gave up the timing, so you cannot keep the cheap rate and also choose when the circuit runs.
The solar twist: midday can now beat the dead of night
This is where the old logic breaks. Controlled load was built for a grid where the cheapest power was overnight. Australia now has so much rooftop solar that the cheapest wholesale power is the middle of the day, when panels flood the grid and the spot price often goes negative. So a heat pump or a solar diverter heating water at midday on your general tariff, powered largely by your own panels, can now undercut an overnight controlled load rate. Controlled load is still cheap and gloriously simple, but for a solar home it is no longer automatically the best place to heat water.
Interactive explainer
Controlled load vs general supply: your hot-water running cost
Slide your yearly hot-water electricity use to see what it would cost on a controlled load rate against the general usage rate. Illustrative rates only, your rates vary, so check your bill.
Hot-water electricity use:
Your yearly saving on controlled load
$/year cheaper
Illustrative only: controlled load assumed at 20 c/kWh and general supply at 33 c/kWh. Your real rates vary by retailer, plan, network and state, so check your own bill. This compares the energy cost only and ignores supply charges, which apply to your general tariff regardless. Single-rate usage rates as of 2026-05-18 ranged roughly from 26 to 44 c/kWh across NEM states (Canstar).
The same numbers, in plain text
Hot-water running cost: controlled load vs general supply
Worked examples at the illustrative rates used in the calculator: controlled load at 20 c/kWh against general supply at 33 c/kWh.
| Household | Hot-water use | Controlled load | General supply | You save |
|---|---|---|---|---|
| Small household (1 to 2 people) | 1,800 kWh/year | $360/year | $594/year | $234/year |
| Average household (3 to 4 people) | 3,000 kWh/year | $600/year | $990/year | $390/year |
| Large household (5 or more people) | 4,200 kWh/year | $840/year | $1,386/year | $546/year |
What this means for real households
How misreading controlled load costs you
The trade above is not academic. It is exactly where households make the wrong call:
They run out of hot water and blame the tank
A growing household on Controlled Load 1 finds the hot water runs cold by evening and assumes the tank is failing. Often the real issue is that CL1 simply does not give the circuit enough hours to reheat. Moving to Controlled Load 2, or a larger tank, fixes it, but only if you understand the rate is about hours, not faults.
They take the cheap rate but lose the timing they needed
Some households sign up for controlled load to save money, then resent that they cannot boost the hot water on demand during the day. The cheap rate and the loss of control are the same deal. You cannot keep one without accepting the other.
They ignore the controlled load line when switching
A household compares two plans purely on the general usage rate and supply charge, switches, and finds the controlled load rate on the new plan is dearer. Because that line is not in the headline numbers, it quietly eats the saving they thought they had locked in.
They keep heating water overnight after going solar
A solar household leaves the hot water on overnight controlled load out of habit, exporting cheap midday solar for almost nothing while paying for overnight grid power. Shifting the heating into the solar window, with a timer or a heat pump, would use their own free daytime power instead.
The insider insight
The off-peak deal was written for a grid that no longer exists
Here is the shift the standard advice has not caught up with. Controlled load was designed decades ago to soak up cheap, surplus baseload power in the dead of night, when coal plants kept running but demand collapsed. Night was the cheap time, so heating water overnight made obvious sense. Australia now has more rooftop solar per person than anywhere on earth, and the cheap, surplus power has moved to the middle of the day. The night-time logic the tariff was built on has quietly inverted.
The non-obvious truth: for a solar household, the smartest place to heat water may no longer be a controlled load at all. A heat pump uses roughly a third of the electricity of a standard element, and a solar diverter or simple timer can push that heating into the midday window your own panels are flooding for free. Run on your own solar, the effective rate can fall below even the cheapest controlled load. Controlled load still wins on simplicity and for homes without solar, but the automatic answer of "just put it on off-peak overnight" is no longer the cheapest answer for everyone.
So the practical lesson is not "avoid controlled load", it is "match the tariff to your home". No solar, standard tank, want it simple? Controlled load is hard to beat. Solar on the roof and a heat pump or timer available? The cheap hours have moved, and your hot water should probably move with them.
Grounded in the analysis
What you should actually do
Moves that follow from how controlled load really trades control for a cheaper rate.
Find your controlled load line on your bill
Check whether your hot water is already on a controlled load and which one. Match it to your household: if you run out of hot water on Controlled Load 1, ask your retailer about Controlled Load 2 or a larger tank rather than abandoning the cheap rate.
Compare the controlled load rate, not just the headline
When you compare plans, read the general usage rate and supply charge, then check the controlled load rate separately on each offer. It is not in the advertised numbers and it can quietly undo the saving you thought you had.
If you have solar, do the midday maths
Rooftop solar has moved the cheap hours to the middle of the day. Price up shifting hot water into the solar window with a timer, or a heat pump on your general tariff, and compare that against your overnight controlled load rate before assuming off-peak still wins.
In a NEM state (QLD, NSW, ACT, VIC, TAS or SA)? Compare electricity plans and check the controlled load rate on each. In WA or the NT there is no retail competition to compare.
Current figures, last updated 2026-06-15
Key controlled load facts and the rates used on this page. Rate context from Canstar; market and network arrangements from the Australian Energy Regulator (aer.gov.au) and your state distributor. Rates and tariffs vary by network, retailer and plan, so confirm on your own bill before relying on them.
The bottom line
Why this matters right now
Controlled load is still some of the cheapest, simplest electricity you can buy, and for a home without solar it is hard to beat. But it is a trade, not a free discount: the rate is low because the network controls the timing, and the timing it was built around, the dead of night, is no longer when power is cheapest. As rooftop solar keeps pushing the cheap hours into the middle of the day, the smart question is no longer "should I put hot water on off-peak", it is "where are the cheap hours for my home, and is my hot water using them". Find your controlled load line, compare the rate when you switch, and if you have solar, do the midday maths before assuming overnight still wins. That is how you turn an understanding of controlled load into a smaller bill, in the states where you can act on it.
Common questions
A Selectra expert answers your questions about controlled load
A controlled load is electricity supplied to a separately metered circuit in your home, most often an electric storage hot water system, and sometimes slab or underfloor heating or a pool pump. Your network operator switches that circuit on only during set off-peak windows, usually overnight, and switches it off the rest of the day. Because you let the network decide when the appliance runs, you pay the cheapest electricity rate in the house for it. It sits on your bill as its own line, separate from your general usage.
They differ in how many hours the circuit is switched on, and therefore in price. Controlled Load 1 gets the fewest hours, typically a block overnight, so the appliance has less time to heat. It carries the lowest rate. Controlled Load 2 gets a longer window that can include some daytime hours, so it suits a smaller tank or a household that runs out of hot water on CL1. It costs a little more per kilowatt hour in exchange for those extra hours. Which one you can have depends on your network and your appliance.
Because you are doing the network a favour. By letting the operator run your hot water or heating only in off-peak windows, you shift that demand away from the evening peak when the grid is strained. Off-peak network charges are far lower, so the network passes that saving on as a cheaper rate. It is a load-shifting incentive: cheap power in return for the network controlling the timing. That is also why you cannot freely choose the hours, the cheap rate exists precisely because you do not.
Yes, and this is the big shift. The cheapest wholesale power in Australia is now the middle of the day, when millions of rooftop panels flood the grid and the spot price often falls below zero. Overnight controlled load was designed for a world where night was the cheap time. If you have solar, heating your water at midday with your own panels, using a timer or a heat pump on your general tariff, can now beat an overnight controlled load rate. Controlled load is still cheap and simple, but it is no longer automatically the smartest option for a solar household.
Not really. The controlled load rate is set by your retailer in line with network charges, and it does not appear in headline plan comparisons, which quote the general usage rate and supply charge. You compare retailers on those numbers, then check the controlled load rate separately on each plan, because it can vary. If you switch retailer in a competitive state, your controlled load usually comes across as its own tariff line. You cannot, however, shop the controlled load on its own.
Controlled load arrangements exist around the country, but the ability to switch retailer does not. In Western Australia, Synergy is the monopoly residential retailer on the main grid, and in the Northern Territory, Power and Water (through Jacana Energy) fills that role. Households there cannot shop retailers, so while you may still have an off-peak hot water tariff, you take the arrangement your provider offers rather than comparing it across retailers. Always check your own bill and network for the exact tariff available.
