South African homeowners could be paying around R300 more for electricity each month without knowing it, according to Matthew Koller, General Manager of Fungi Utilities. He says the extra cost comes from hidden overnight consumption that follows power outages.
Koller’s team examined more than 400 million meter readings from almost 3,900 homes in residential estates across Johannesburg, Pretoria, Cape Town and KwaZulu-Natal. The August 2026 data set showed an overnight baseline of about 0.45 kilowatt-hour (kWh) per household. A kilowatt-hour is the amount of energy used by a 1,000-watt appliance running for one hour.
How appliance resets add cost
The baseline covers equipment that is always on, such as Wi-Fi routers, security systems, electric fence energisers and fridges or geysers that run on timers or thermostats. Koller’s testing found that after a power interruption, some appliances draw more power. A geyser that normally uses roughly 354 watts increased to about 370 watts when the main breaker was switched off and power was restored. A tumble dryer showed an even larger spike, reaching about 542 watts.
At the electricity rates used in the analysis, the geyser costs roughly R1.47 per hour under normal operation and R1.53 per hour after the reset. The tumble dryer costs about R2.24 per hour. Those extra watts may seem small, but when several appliances restart together, the extra kilowatt-hours accumulate quickly.
Timers can lose their settings after an outage, causing geysers, pumps, heating equipment and other automated devices to run at the same time. In areas where block tariffs increase with higher usage, the extra consumption can push a household into a more expensive block. Running a heavy appliance after midnight does not automatically make it cheaper; it simply hides the usage from immediate view.
National Energy Regulator of South Africa (NERSA) approved tariff increases for 2026/27 of 8.76% for Eskom direct customers and 9.01% for municipal customers. Koller notes that for a home that uses around 600 kilowatt-hours a month, those increases already add R180 to R220 to the bill before any resets are considered.
He recommends starting an audit by checking geyser timers, thermostats and heating elements, then moving on to pools, boreholes and circulation pumps. Homeowners should also compare their overnight baseline over several days and investigate any sustained rise. Simple steps such as checking refrigerator seals, improving ventilation, adjusting temperature settings and switching off non-essential electronics at the wall can reveal whether the baseline drops.
In estates that use sub-meters, several properties running large appliances at the same time can raise the estate’s overall demand. The estate’s main supply may sit on a municipal bulk or commercial tariff, so coordinated spikes can increase the central account that is ultimately passed on to residents.
When the extra kilowatt-hours from mis-configured timers, baseline creep and occasional appliance resets are added to the tariff hikes, Koller says the combined impact can push a typical bill up by R500 a month. Homeowners who notice a higher overnight baseline should act quickly to avoid the hidden cost.
