Flat Rate vs Time of Use Electricity: Which Saves You More?

By Sarah Jenkins | 2026-04-27 | Category: Energy

Time of Use pricing is now the default for most Australian households. But is it actually cheaper than a flat rate? The answer depends on your lifestyle.

One of the most consequential electricity plan decisions Australian households make — and one that is often made by default rather than by choice — is whether to be on a flat single rate or a time-of-use (TOU) tariff. The wrong choice can cost hundreds of dollars per year. The right choice, depending on your household's consumption pattern, can save a comparable amount. This guide explains how each tariff structure works, walks through the calculation you need to make for your specific situation, and gives you a framework for deciding which suits you in 2026.

How Flat Rate (Single Rate) Tariffs Work

A flat rate tariff — also called a single rate or anytime tariff — charges the same price per kilowatt-hour (kWh) for every unit of electricity you consume, regardless of the time of day, day of week, or season. If your flat rate is 28 cents/kWh, you pay 28 cents whether you run your dishwasher at midnight on a Sunday or at 6 PM on a weekday. The simplicity of flat rate pricing is its primary appeal: your bill is entirely predictable from your consumption alone.

Flat rate tariffs are compatible with all meter types — basic accumulation meters (Types 5 and 6) can only support flat rate billing, while smart interval meters (Types 1–4) can support either flat or TOU tariffs. If you have a basic meter, flat rate is your only option. If you have a smart meter, you can choose either tariff type from your retailer.

Flat rate usage charges in 2026 range from approximately 24 cents/kWh (cheapest competitive market offers) to 38 cents/kWh (standing offers) in NSW. In Victoria, where all customers have smart meters, the effective single rate for the cheapest plans starts around 23 cents/kWh. Daily supply charges (fixed daily cost regardless of consumption) are typically $0.85–$1.10 per day under flat rate plans.

How Time-of-Use (TOU) Tariffs Work

A time-of-use tariff charges different rates depending on when you use electricity. The rate structure divides the day into periods reflecting the cost of electricity generation and network demand at those times. Periods of high demand and constrained grid capacity are "peak" periods, charged at a premium rate. Periods of low demand and abundant grid capacity are "off-peak," charged at a discounted rate. Many TOU structures include a third "shoulder" rate for intermediate periods.

The exact period definitions vary by state and retailer, but the most common structure in eastern Australia is: Peak — 2 PM to 10 PM on weekdays (rates: 40–55 cents/kWh); Shoulder — 7 AM to 2 PM and 10 PM to 11 PM on weekdays, plus 7 AM to 10 PM on weekends (rates: 22–30 cents/kWh); Off-Peak — 11 PM to 7 AM daily (rates: 12–20 cents/kWh). Some plans simplify to peak and off-peak with no shoulder period.

TOU plans require a smart interval meter (Types 1–4) to implement, because billing must record which half-hour intervals electricity was consumed and charge accordingly. This is why TOU is universal in Victoria (100% smart meter coverage) and increasingly available elsewhere as rollouts proceed.

Controlled Load: A Special Form of Off-Peak Pricing

Controlled load (CL) tariffs are distinct from time-of-use pricing, though they are often confused. A controlled load circuit is a separately metered circuit — typically connected to an electric storage hot water system or underfloor heating — that the electricity distributor switches on and off remotely to balance network load. The distributor sends power to controlled load circuits during low-demand periods (usually overnight and during low-use daytimes) and cuts them during peak periods.

Controlled load rates are typically 13–18 cents/kWh for CL1 (overnight, 10 PM to 7 AM) and 14–20 cents/kWh for CL2 (overnight plus brief daytime periods). These are substantially below both the flat rate and TOU off-peak rate, making them the cheapest available electricity for eligible appliances. The trade-off is that you have no control over the exact heating cycle timing — the distributor controls when the CL circuit is energised, within the approved window.

If your home has an electric storage hot water system and the plumbing supports a CL circuit (many do, particularly in homes built before the 1990s), ensuring it is correctly connected to a CL rate is one of the highest-return simple actions available. It requires no new equipment — just a request to your distributor to verify the circuit and tariff assignment.

The Calculation: Which Is Cheaper for Your Household?

The decision between flat rate and TOU comes down to a straightforward calculation: what proportion of your total annual consumption falls in each TOU period, and how does the cost under TOU compare to the cost under the flat rate for your specific usage pattern?

Here is a worked example for a typical Sydney family consuming 7,000 kWh per year. Assume the flat rate is 28 cents/kWh and the TOU structure is: peak 50 cents (3 PM–9 PM weekdays), shoulder 26 cents, off-peak 15 cents. The family's usage analysis (from their smart meter data) shows 28% peak, 48% shoulder, 24% off-peak:

Under flat rate: 7,000 × $0.28 = $1,960 per year. Under TOU: (0.28 × 7,000 × $0.50) + (0.48 × 7,000 × $0.26) + (0.24 × 7,000 × $0.15) = $980 + $873.60 + $252 = $2,105.60 per year. In this case, flat rate is cheaper by $145.60 per year.

Now the same family shifts behaviour: they schedule all timer-controlled appliances (dishwasher, washing machine, hot water boost) to off-peak periods, moving the usage split to 15% peak, 45% shoulder, 40% off-peak: (0.15 × 7,000 × $0.50) + (0.45 × 7,000 × $0.26) + (0.40 × 7,000 × $0.15) = $525 + $819 + $420 = $1,764 per year. Now TOU is $196 cheaper than flat rate. The conclusion: TOU is only beneficial if you actively manage your usage to shift loads to off-peak periods. Without behaviour change, flat rate is often cheaper.

Who Should Choose Flat Rate?

Flat rate is the better choice for households that: have high usage concentrated in the 3 PM to 9 PM peak window and cannot shift it (families with young children, households where all members are home during the evening peak, homes with medical or care requirements demanding continuous power during evenings); lack the flexibility or inclination to manage appliance timing actively; have older, non-timer-equipped appliances that cannot be scheduled automatically; are on basic meters without smart meter access; or simply prefer predictable billing with no time-of-day complexity.

Flat rate plans offer simplicity and, for the right usage profile, competitive total annual cost. The growing availability of flat rates from very competitively priced mid-tier retailers means a flat rate customer on the best available plan is not necessarily at a disadvantage compared to a TOU customer on a standard plan. The combination of a cheap flat rate plus efficient appliances can outperform a TOU plan with no behaviour optimisation.

Who Should Choose Time-of-Use?

TOU delivers superior value for households that: have relatively low consumption in the 3 PM to 9 PM weekday peak window (both adults working away from home until after 7 PM, households in school-age years where evening consumption is lower); have smart timer-capable appliances (dishwashers, washing machines, hot water controllers) that can be set to run overnight or early morning; have electric vehicles that can be programmed to charge overnight at off-peak rates; have rooftop solar that generates during shoulder and off-peak hours (morning and afternoon); or have home batteries that can be charged off-peak and discharged during peak hours.

The EV charging use case is particularly compelling. A 60 kWh EV battery charged entirely on off-peak electricity at 15 cents/kWh costs $9 per full charge. The same charge on a flat rate at 28 cents/kWh costs $16.80. For a household charging 250 km of driving range per week (roughly 30 kWh), the annual saving from off-peak charging versus flat rate is approximately $290 — paid back immediately, every year, without any capital investment beyond the EV itself.

Solar Households: A Special Consideration

For households with rooftop solar, the tariff decision is more nuanced because solar generation itself is concentrated in the shoulder period (10 AM to 2 PM). This means solar offsets shoulder-period consumption effectively under TOU but does not help with peak-period grid draws in the evening. If your solar system's generation drops to near zero by 4 PM and your household peak electricity use is between 5 PM and 8 PM, you will pay the TOU peak rate for all your evening consumption — and there is no way to avoid this without battery storage.

For solar households without batteries, the choice depends on how much your solar generation eliminates your need to draw from the grid during shoulder periods (where TOU shoulder rates compare favourably to flat rate) versus how much evening peak consumption you have (where TOU peak rates are much higher than flat rate). Modelling with your actual smart meter and solar generation data is the most reliable way to make this determination. The Victorian Energy Compare tool and some commercial comparison platforms provide this solar-aware comparison capability.

Switching Tariff Types

Switching from flat rate to TOU (or vice versa) is a matter of requesting the change from your electricity retailer or signing up with a new retailer on the desired tariff type. The switch typically takes effect at your next meter read for basic meter customers, or within three business days for smart meter customers. There is no fee for switching tariff types.

Before making the switch, access your historical half-hourly consumption data from your retailer's online portal (available to all smart meter customers). This data allows you to see your exact usage profile — including what proportion falls in each TOU period — and model your cost under both tariff options with precision. Do not make the tariff switch decision based on general advice alone; your personal usage profile is the determining factor.

Frequently Asked Questions

My retailer offers a "solar sponge" tariff. Is that different from TOU?

Yes. A solar sponge or solar soaker tariff adds a super-cheap midday rate (typically 0–8 cents/kWh, sometimes free) during peak solar generation hours (roughly 10 AM to 3 PM). This structure rewards households that shift large loads — hot water, pool pumps, EV charging — to run during the solar generation window when grid electricity is abundantly cheap. Solar sponge tariffs are available from Amber Electric, Origin Spike, and some other retailers, and are particularly effective for households with a home office or daytime occupants who can schedule consumption manually during the day.

Does TOU mean I cannot use electricity during peak hours?

No. TOU does not restrict when you can use electricity — it only changes the price. You can use as much electricity as you like during peak hours; you simply pay the premium peak rate. TOU is about price signals, not rationing. The decision to reduce peak consumption is entirely your choice, driven by the financial incentive of the lower off-peak rate.

Demand Tariffs: The Third Tariff Type

A third electricity tariff type is emerging in parts of Australia that is not widely discussed in standard consumer guides: the demand tariff (also called capacity tariff or peak demand charge). Demand tariffs charge based on your highest consumption in any single 30-minute interval during the billing period — your "peak demand" — rather than (or in addition to) your total consumption. Network businesses use demand tariffs for large business customers and are beginning to introduce them for residential customers in congested network areas.

Under a demand tariff, a household that runs the oven, air conditioner, EV charger, and pool pump simultaneously for just one 30-minute period in a month incurs a high demand charge for that spike — even if their total monthly consumption is average. The financial incentive is to smooth your consumption profile and avoid simultaneous operation of multiple large appliances, rather than simply reducing total consumption or shifting to off-peak hours.

Demand tariffs are currently rare for residential customers in Australia, but the Ausgrid and SA Power Networks distribution businesses have consulted on demand tariff structures for residential customers in congested suburbs. If demand tariffs are introduced in your area, the optimal response is to install a home energy management system (or smart power board) that detects when multiple large appliances are drawing power simultaneously and schedules them sequentially rather than concurrently.

TOU for Renters: What Is Possible Without Smart Meter Modifications

Renters who want to benefit from TOU pricing can do so without any physical modifications to the property's electrical infrastructure — all that is required is a smart interval meter, which is already installed in most rental properties in Victoria and increasingly common elsewhere. The tenant simply needs to contact their electricity retailer and request to switch to a TOU plan. The retailer updates the billing configuration associated with the smart meter to TOU rates without any technician visit or physical work.

For renters in NSW, QLD, or SA who have a basic meter (not smart meter), TOU pricing requires a smart meter installation. This can be requested from the distribution network (not the retailer) at no cost in most states, though scheduling may involve a wait of several weeks. The renter must typically notify the landlord that a smart meter installation is requested — this is a notification, not a request for consent, as meter upgrades are the distributor's prerogative — but in practice most landlords raise no objection to a free network upgrade that does not require any internal work.

Calculating Your Ideal Tariff: A Step-by-Step Guide

Follow these steps to determine whether flat rate or TOU is better for your household. Step 1: log in to your electricity retailer's online portal and download your half-hourly consumption data for the past 12 months. Step 2: categorise each half-hourly interval as peak, shoulder, or off-peak based on your retailer's TOU period definitions (check their website or call them). Step 3: sum the consumption in each period category to get your annual kWh in each period. Step 4: multiply each period's kWh by the respective TOU rate and sum — this is your annual TOU cost (usage only). Step 5: multiply your total annual kWh by the flat rate — this is your annual flat rate cost (usage only). Step 6: add the daily supply charge for 365 days to both calculations. Step 7: compare and select the lower total.

If you cannot access historical interval data (for example, if you have a basic meter), you can estimate the calculation using typical usage pattern percentages for households similar to yours. A household with both adults working away from home 9 AM to 6 PM on weekdays might estimate 20% peak, 50% shoulder, 30% off-peak. A household with a stay-at-home parent and school-aged children might estimate 35% peak, 45% shoulder, 20% off-peak. These estimates are less accurate than actual data but provide a useful approximation for the comparison.

Demand Tariffs: A Third Option Worth Considering

Beyond flat-rate and time-of-use tariffs, a third billing model — demand tariffs — is worth understanding for households with variable consumption patterns. Demand tariffs charge a fixed monthly fee based on your peak demand reading (the highest 30-minute average power draw recorded during the billing period) rather than or in addition to per-kWh usage charges.

For households where peak demand events are occasional and manageable — for example, one particularly heavy usage evening per month — demand tariffs can produce bills substantially lower than both flat-rate and TOU alternatives. A household that routinely limits simultaneous appliance use (never running the oven, dishwasher, and electric vehicle charger at the same time) may find a demand tariff rewards their behaviour with significant savings.

The risk is that a single unavoidable high-demand event — a hot day requiring sustained air conditioning, or a guest stay that strains the household's electrical load — can set a high monthly demand charge that persists for the entire billing period. Demand tariffs suit households with smart home automation capable of automatically limiting load during potential peak periods, not those who want a set-and-forget billing arrangement.

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