As every year, the end of October marks the beginning of the darker season. On 25 October, we will turn the clocks back by one hour. After that, daylight hours will end even earlier. Daylight saving time was originally introduced during the First World War to help reduce energy consumption during the summer months, but does it still deliver savings today?
A System Dating Back to the First World War
The practice of switching between summer and winter time was first introduced in Europe during the First World War, when countries were looking for ways to conserve coal and other energy resources. Longer daylight hours in the evening were expected to reduce the need for artificial lighting. Since lighting accounted for a significant share of energy consumption at the time, this approach could indeed generate savings.
According to Tiit Hõbejõgi, Member of the Management Board of Enefit and Head of Energy Trading, modern electricity consumption is influenced by far more factors, while the share of lighting in total energy use has become significantly smaller. Although people tend to switch on lights earlier after the clocks change, this does not automatically result in a noticeable increase in household electricity costs.
“Many people assume that lighting is one of the main sources of household electricity consumption. In reality, modern LED bulbs use very little electricity, and the cost of running a single bulb for an additional hour is generally minimal,” explained Hõbejõgi. “Of course, the total impact depends on the number of light fixtures, their wattage, and how long they are left on. However, even extensive use of modern lighting is unlikely to have a significant effect on a household’s electricity bill.”
Several scientific studies have also questioned whether daylight saving time still delivers energy savings under modern conditions. Some research even suggests that overall energy costs may increase due to shifting heating and cooling needs. While both our lifestyles and the structure of electricity consumption have changed significantly over the past century, the clock-changing system remains in place across all European Union countries. Ultimately, household energy costs depend far more on consumption habits than on a one-hour shift in the clock.
What Does One Extra Hour of Lighting Cost?
Calculating the cost of an additional hour of lighting is straightforward. Simply multiply the power consumption of a lamp by the duration of use and the electricity price. For example, a 10-watt LED bulb consumes 0.01 kilowatt-hours (kWh) of electricity in one hour. If that bulb is used for one extra hour daily, electricity consumption increases accordingly.
Consider a typical two-room apartment with three light fixtures in the living room, two in the bedroom, three in the kitchen and two in the bathroom, for a total of ten bulbs. Assuming that each bulb has a power rating of 10 watts, their combined electricity consumption amounts to 0.1 kWh per hour. Over the course of a month, this translates into approximately 3.1 kWh of additional electricity use resulting from the earlier onset of darkness after the clock change.
Using Estonia’s average day-ahead electricity price for September of 9.29 cents per kWh, including VAT and other charges, that additional hour of lighting would increase monthly costs by approximately €0.29. This calculation assumes that all ten lights are switched on during the additional hour.
Bigger Savings Can Be Found Elsewhere
Household electricity consumption depends on many factors, including appliances, heating and cooling systems, hot water production, electric vehicle charging and other energy needs. As a result, the most effective way to reduce electricity bills is to identify the devices that consume the most energy and, for customers on market-based electricity plans, pay attention to when they are used.
“If we want to reduce electricity costs, it is important to distinguish between habits that have a major impact on the bill and those whose impact is marginal. LED lighting is already a highly energy-efficient solution. Much greater savings can often be achieved through well-chosen household appliances and their thoughtful use,” said Hõbejõgi.
For example, if using a washing machine or dishwasher can be postponed without causing inconvenience, it is worth checking current electricity prices beforehand.
“Rather than worrying about a daily schedule that has shifted by one hour, people should focus on habits that have a greater impact on their electricity bill. We change the clocks only twice a year, but we have the opportunity to use electricity more efficiently every day,” Hõbejõgi concluded.
