Prepaid electricity users across Gauteng often notice that they receive fewer electricity units later in the month, even when spending the same amount of money. This affects households supplied by municipalities such as Johannesburg and Tshwane, where residential electricity tariffs are structured using inclining block tariffs. The issue matters now as electricity costs continue to rise and more households rely on prepaid meters to manage tight monthly budgets.
According to municipal tariff frameworks and energy sector explanations, the change in units is usually not caused by the day electricity is purchased, but by how much electricity a household has already used within a calendar month and which tariff block applies at the time of purchase.
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How Prepaid Electricity Is Charged in Most Municipalities
Prepaid electricity operates through the purchase of electricity units measured in kilowatt hours. Consumers buy units through a vending platform, receive a token, and load it onto a prepaid meter.
In many Gauteng municipalities, electricity is not charged at a single flat rate. Instead, residential customers are billed using an inclining block tariff system, where the price per unit increases as monthly electricity consumption rises.
This tariff structure applies to both prepaid and conventional meters and is approved through municipal budget and tariff processes.
What Inclining Block Tariffs Mean in Real Life
Inclining block tariffs divide electricity pricing into several usage blocks within a calendar month. The first block is charged at the lowest rate per kilowatt hour. Once a household reaches the limit of that block, any additional electricity is charged at a higher rate in the next block.
As usage continues to increase through the month, the household moves into higher blocks, each with a higher price per unit. This is why two households spending the same amount may receive different numbers of units if their monthly consumption levels differ.
How Electricity Tariff Blocks Affect the Units You Receive
Under an inclining block tariff structure, electricity usage is measured cumulatively over a calendar month.
While block thresholds differ by municipality, the structure generally works as follows:
- Block 1 covers the first portion of electricity used in a month and is charged at the lowest rate per unit
- Block 2 applies once the first threshold is reached and is charged at a higher rate
- Block 3 and above apply as consumption increases further, with each block carrying a higher price per unit
Once a household crosses into a higher block, all additional electricity purchased or consumed is charged at that higher rate until the end of the month.
At the start of a new calendar month, the usage counter resets, and the household begins again in the lowest-priced block.
Why the Start of the Month Feels Cheaper
Many prepaid electricity systems reset usage counters at the beginning of a new calendar month. When this happens, the next electricity purchase starts again in the lowest tariff block.
As a result, electricity bought early in the month is more likely to be priced mostly within the cheapest block. Electricity bought later in the month may fall partly or entirely into higher-priced blocks if the household has already used significant electricity.
The perception that electricity is cheaper at the beginning of the month is therefore linked to tariff resets rather than a discount based on the calendar date itself.
Does Splitting Purchases Change the Total Units You Get
A common belief is that buying electricity in smaller amounts throughout the month results in more units. In most cases, this is not accurate.
What determines how many units a household receives is the total monthly consumption within the block tariff system. Whether electricity is bought in one large purchase or several smaller purchases, the household will still move into higher blocks once usage thresholds are reached.
However, transaction fees charged by different vendors can influence the final value of each purchase, especially where fees apply per transaction.
Where You Buy Can Change the Final Cost
Some prepaid electricity vendors charge service or transaction fees, while others charge little or nothing.
Households using platforms with higher fees may receive fewer units for the same rand value, even if tariff blocks are identical. Multiple purchases through fee-charging channels can increase overall costs, independent of the tariff structure.
This is why two households in the same area can report different experiences even when they use similar amounts of electricity.
Why Unused Units Can Become Expensive Later
In many prepaid systems, unused electricity units carry over into the next month. While this prevents loss of purchased electricity, it can result in higher effective costs under inclining block tariffs.
If electricity is purchased late in the month after the household has entered higher tariff blocks and not all units are used, those higher-priced units may carry into the next month. This means the household may start the new month using electricity bought at a higher per-unit cost, even though the tariff counter has reset to the lowest block.
Municipal guidance has therefore consistently indicated that large end-of-month purchases can increase average electricity costs over time.
Gauteng Examples of How Tariffs Are Structured Wrong
Tariff block sizes and pricing differ across Gauteng municipalities and household categories.
Households in Johannesburg may face different block thresholds from those in Tshwane. Indigent registered households may also fall under alternative tariff structures designed to support low-income users.
Municipal electricity tariffs are reviewed annually and can change following budget approvals and regulatory processes.
What This Means for Gauteng Residents
For Gauteng residents, the key factor influencing how many electricity units are received is how far into the monthly tariff blocks a household has progressed at the time of purchase.
Electricity purchased before heavy monthly usage is more likely to fall within cheaper blocks. Electricity purchased after higher usage is more likely to be priced in higher blocks. In addition, vending fees can reduce the effective value of prepaid purchases.
Understanding both tariff block progression and transaction costs has become increasingly important as electricity affordability remains under pressure across the province.
Key Factors That Affect How Many Units You Receive
- Total electricity consumed within the calendar month
- Tariff block thresholds set by the municipality
- Whether the household is on a standard or an indigent tariff
- Transaction or service fees charged by the vendor
- Number of purchases made during the month
- Amount of unused electricity carried into the next month
FAQ’s
Is prepaid electricity cheaper at the beginning of the month
It often appears cheaper because many tariff systems reset to the lowest block at the start of a new calendar month.
Does buying one large token give more units than buying smaller ones
Not necessarily. Total monthly usage determines when higher blocks apply.
Do unused prepaid units expire
In most systems, unused units carry over into the next month.
Why do households in the same area get different units
They may be in different tariff blocks or use vendors with different transaction fees.
Are all Gauteng municipalities on the same tariff system
No. Tariff structures and block thresholds differ by municipality.
What Happens Next
Municipal electricity tariffs continue to be reviewed through annual budget processes, meaning block thresholds and pricing may change from one financial year to the next.
For Gauteng prepaid users, clearer communication around tariff structures and vending costs remains a key accountability issue as households adjust to rising electricity expenses and changing consumption patterns.
