As the summer heat drives up the use of air conditioning and other cooling devices, households are facing increased electricity bills. A key figure to watch in residential electricity rates during the summer months is the monthly usage of 450 kWh (kilowatt-hours).
According to Korea Electric Power Corporation's (KEPCO) electricity rate table on July 13, a low-voltage residential customer using 450 kWh in July and August can expect a bill of 85,740 won. If usage increases to 451 kWh, the estimated bill rises to 92,530 won, an increase of 6,790 won.
This calculation is based on low-voltage residential customers without applying discounts for large families, multiple children, or automatic payment. The amount includes value-added tax and the electricity industry fund but excludes TV reception fees. Actual bills may vary based on contract type, discounts, and billing periods.
Summer low-voltage rates are divided into three tiers based on usage. The base fee is 910 won for usage up to 300 kWh, 1,600 won for 301 to 450 kWh, and 7,300 won for usage exceeding 450 kWh. The energy charge is 120 won per kWh for the first 300 kWh, 214.6 won for the next 150 kWh, and 307.3 won for any usage above 450 kWh. The summer tiered pricing applies from July 1 to August 31.
The significant increase in estimated charges when moving from 450 kWh to 451 kWh is primarily due to the base fee. When usage is at or below 450 kWh, the base fee is 1,600 won, but it jumps to 7,300 won as soon as usage exceeds that threshold, an increase of 5,700 won.
Additionally, the energy charge of 307.3 won per kWh, along with a climate environment fee of 9 won and a fuel cost adjustment fee of 5 won, contribute to the increased electricity bill. The final increase of 6,790 won includes value-added tax of 10% and the electricity industry fund of 2.7%, with any amount under 10 won rounded down.
However, exceeding 450 kWh does not mean that the entire usage is charged at the rate of 307.3 won per kWh. For instance, if 451 kWh is used, the first 300 kWh is charged at the first-tier rate of 120 won, the next 150 kWh at the second-tier rate of 214.6 won, and only the excess 1 kWh is charged at the third-tier rate of 307.3 won. The main reason for the sudden spike in charges is not the retroactive application of a higher rate to the total energy usage, but rather the abrupt change in the base fee.
In a similar scenario, if monthly usage increases from 419 kWh to 484 kWh, the estimated bill rises from 77,760 won to 104,480 won. While energy usage increases by 65 kWh, or about 15.5%, the bill rises by 26,720 won, or approximately 34.4%. This is due to the increase in the base fee and the application of the third-tier energy charge on the excess usage.
The government and KEPCO operate the residential tiered pricing more broadly during the high cooling demand months of July and August. While other seasons have tiers based on 200 kWh and 400 kWh, the summer tiers are expanded to 300 kWh and 450 kWh, respectively.
Electricity rates for the third quarter of this year remain frozen at current levels. KEPCO has maintained the fuel cost adjustment rate at 5 won per kWh for the July to September period. The base fee, energy charge, and climate environment fee have also not been adjusted separately.
For households with high-voltage residential rates, the base fee and energy charge differ, leading to variations in bills and increases even for the same usage. Households that include electricity costs in their apartment management fees may also see differences in actual costs based on the contract type and distribution of common electricity charges.
To assess the burden of summer electricity bills, it is essential to consider not only the billed amount but also the cumulative monthly usage and contract type. Particularly for low-voltage residential customers nearing the 450 kWh threshold, whether they exceed that limit will affect their base fee.
* This article has been translated by AI.
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