The 801st Unit: Why One Extra kWh Can Add RM39 to Your Electricity Bill

On Thursday, 15 October 2026, Deputy Prime Minister Datuk Seri Fadillah Yusof, who is also the Minister of Energy Transition and Water Transformation, told the Dewan Rakyat why household electricity bills have been rising. Gas and coal prices through the second and third quarters of the year, he said, ran far above the levels the current tariff was set for, which he put down to tensions in West Asia and disruption in the Strait of Hormuz. That extra cost reaches bills through a line called the Automatic Fuel Adjustment, or AFA.

For most homes, that line is currently zero. Until 31 December 2026, domestic customers who use 800 kWh or less in a month pay no AFA, no retail charge and no SST. The minister put 800 kWh at about RM328 a month, and said around eight million households in Peninsular Malaysia, roughly 90 per cent of them, are covered. The wider protection was announced on 18 September and backdated to 1 September.

That is good news for the 90 per cent. But the way the protection works creates a cliff right at its edge, and it is worth knowing exactly where the cliff is.

According to TNB, once a household is over the threshold, AFA is charged on the month's total consumption, not just on the units above the line. So the protection is all or nothing. At 800 kWh you pay no AFA at all. At 801 kWh you pay it on all 801.

For October, the Energy Commission set AFA at 3.61 sen per kWh. Work out 801 units of it from the left. Eight hundred times 3.61 sen is 2,888 sen, or RM28.88. The last unit adds another 3.61 sen, so the AFA on 801 kWh comes to RM28.92. Add the RM10 retail charge, which also comes back once you pass 800, and that 801st unit has brought RM38.92 with it, before SST.

Compare that with what a unit of electricity normally costs. The generation, capacity and network charges on a typical home add up to about 44 sen per kWh before any rebate. So crossing the line costs close to ninety times what the unit itself does.

Turn it around and the cliff becomes useful to know about. A household sitting just above 800 kWh saves far more by getting under it than the units alone suggest. Cutting from 820 kWh to 790 kWh saves roughly RM13 for the 30 units themselves, at about 44 sen each. But it also removes the AFA on all 820 units, which is RM29.60 at October's rate, and the RM10 retail charge. That is more than RM50 saved for a cut of under 4 per cent.

To aim for a number, it helps to know what a kilowatt-hour actually is. It is simply power multiplied by time: 1,000 watts running for one hour. So an air conditioner drawing 1,000 watts for eight hours a night uses 8 kWh a night, or 240 kWh over a 30-day month. A 10-watt LED bulb, on the other hand, needs 100 hours to use a single kWh. The appliances with the highest wattage that run the longest are the ones that decide which side of 800 you land on. Switching off a light is a good habit, but it is rarely what moves a home across the line.

The cliff is about to move. From 1 January 2027 the threshold goes back to 600 kWh, and the published three-month outlook projects AFA at 7.59 sen per kWh for January, more than double October's rate. On those numbers, the 601st unit would bring AFA on all 601 units, about RM45.62, plus the RM10 retail charge. Projections can change before then, and the government is reported to be in talks with TNB and the regulator on measures for 2027. So treat this as a sum to redo in January, not a forecast.

To see which side of the line you are on, look at the kWh figure on your bill or in the myTNB app rather than the ringgit total. The threshold is set in units, not in money, and the units are what you can actually control.

None of the arithmetic here is more than multiplying by a decimal and adding a fixed charge, which is exactly the kind of sum congak trains. Doing it from the left, with the 800 lots first and the remainder after, gets you to within a sen in a few seconds. The daily challenge at cerdikcerdik.com/math practises that habit in a few minutes a day.