The line on the product page reading "about 107 won of electricity per cycle" assumes a 5kg standard course with eco mode switched on. The machine is a 9kg unit, yet the reference load is 5kg — and the quoted standard drying time of about 78 minutes is measured in speed mode, so two different sets of conditions sit side by side on one screen. The figures come from LG Electronics' published dual-inverter heat-pump dryer (RH9SGN) specification.
Take that 107 won apart and the rate used to compute it becomes visible. The same page lists energy use per cycle at the equivalent of 0.5kWh, so 107 ÷ 0.5 = 214 won per kWh. That is effectively identical to KEPCO's second-tier residential low-voltage energy charge of 214.6 won per kWh — meaning the calculation excludes the climate and environment levy, VAT, and the electricity industry infrastructure fund.
The same kWh runs from 145 to 356 won
A Korean residential bill is built from a base charge, an energy charge, a climate levy and a fuel-cost adjustment, with a 2.7% industry fund contribution and 10% VAT applied on top. The climate levy is a flat 9.0 won per kWh regardless of contract type. The residential low-voltage tariff table as of 15 June 2026 sets out the base and energy charges by consumption tier.
Combining those items into the marginal cost of one additional kWh gives the table below. The tax and fund uplift totals 12.7%, so the figures are multiplied by 1.127.
| Consumption tier | Base charge (KRW/household) | Energy charge (KRW/kWh) | Plus climate levy (KRW/kWh) | Marginal rate after tax and fund (KRW/kWh) |
|---|---|---|---|---|
| Up to 200kWh | 910 | 120.0 | 129.0 | 145.4 |
| 201–400kWh | 1,600 | 214.6 | 223.6 | 252.0 |
| Over 400kWh | 7,300 | 307.3 | 316.3 | 356.5 |
The gap between the first and third tiers is 2.45 times. That is why dryer running costs are said to differ household by household — what sets the amount is not the appliance but which tier the home's monthly consumption sits in. Between the quoted 214 won and the third-tier marginal rate of 356.5 won there is a factor of 1.67, so for some households the same machine's 107 won reads as 178 won.
Recomputing 0.5kWh at the tier marginal rates gives 126 won in the second tier and 178 won in the third. The label figure of 107 won is the number where the most favourable test condition and the lowest rate overlap.
Monthly cost by energy use per cycle
Drop the per-cycle figure from a product label into the table below to get the monthly burden. The basis is 16 cycles a month, and the amounts are the pure incremental charge, excluding any change in the base charge.
| Per cycle (kWh) | Monthly use (kWh) | 201–400kWh tier (KRW) | Over 400kWh tier (KRW) | Difference (KRW) |
|---|---|---|---|---|
| 0.5 | 8.0 | 2,016 | 2,852 | 836 |
| 1.0 | 16.0 | 4,032 | 5,704 | 1,672 |
| 1.5 | 24.0 | 6,048 | 8,556 | 2,508 |
| 2.0 | 32.0 | 8,064 | 11,408 | 3,344 |
| 2.5 | 40.0 | 10,080 | 14,260 | 4,180 |
One item is missing from that table: the jump in the base charge when a new tier is crossed. A household using 390kWh a month that runs a 2.0kWh-per-cycle dryer 16 times adds 32kWh, reaching 422kWh, and the base charge leaps from 1,600 to 7,300 won — a 5,700 won increase, or 6,424 won once tax and fund are applied. Separately from the charge on the extra consumption, crossing the threshold adds 6,424 won on the base-charge line in that month.
What determines a dryer's electricity cost is not its efficiency grade but which side of the 400kWh line the household sits on.
What the efficiency label actually measures
Clothes dryers rated at 3,000W or less fall under Korea's energy efficiency grade labelling scheme. The grade is set not by absolute consumption but by an efficiency index dividing the model's monthly energy use by its maximum energy use (HVAC&R Journal). The relative nature of that measure matters: a grade-one product is not always the one that draws the least electricity in absolute terms, and larger-capacity machines can be structurally advantaged in the grading.
So rather than comparing grade numbers, look at the reported measurements. Grade, energy use, capacity and annual energy cost by model can be searched on the Korea Energy Agency's efficiency management portal. On published specifications, three values are worth checking: energy use per cycle or per month, the test conditions behind that value (load in kg and course), and rated power draw. A figure quoted without the second of these cannot be set beside another product.
Where heat-pump and heater designs diverge on paper
A heat-pump dryer circulates refrigerant to dry at low temperature; a heater design warms air with a resistive element. On published specifications the difference surfaces in two fields. One is rated power draw, which runs higher on heater designs, pushing them nearer the 3,000W threshold for the labelling scheme. The other is standard drying time, which lengthens on heat-pump machines because they work at lower temperature. The 78 minutes quoted above is a speed-mode figure; the standard course runs longer.
In cost terms the gap between the two designs reads straight off the rows of the table above. A 0.5kWh-per-cycle machine and a 2.0kWh one differ by 8,556 won a month at 16 cycles in the top tier. Add the 6,424 won base-charge jump calculated earlier and the monthly spread can approach 15,000 won. Heating and cooling appliances can be approached the same way; the sizing sequence is set out in how to size an air conditioner by floor area.
Who this suits
A household already past 400kWh a month is better served, arithmetically, by treating per-cycle energy use as the first criterion. Every additional unit is charged at 356.5 won per kWh, so small differences in the labelled figure are amplified directly. Conversely, in a one- or two-person home staying inside 200kWh, the marginal rate of 145.4 won cuts the cost gap between designs by more than half; in that band, drying time and capacity are the more sensible priorities.
The case for waiting is when the test conditions are not disclosed. A product listing only a per-cycle cost, without the measurement course and load in kg beside it, is not comparable. The right order is to wait for the reported figures on the efficiency portal and then line up like with like. If indoor humidity is part of the picture, it is worth reading alongside dehumidifier capacity criteria.