Daylight-saving time (DST) is a practice of advancing the clock by one hour during the summer months to provide more usable daylight in the evening. One potential benefit of DST is that it can result in lower energy consumption.
The abolition of daylight saving time is a frequently – and heatedly – debated issue. Frequently, only the aspect of electricity consumption due to artificial lighting is taken into account. Researchers have now examined whether daylight saving has an effect on the amount of heating and cooling energy required for office buildings, and what role climate change may play in this. The results should please proponents of daylight saving time.
With the start of daylight-saving time, debates erupt, as they do every year, about whether or not the time change should be abolished, both in politics and in society at large. Opponents argue that the time change has an impact on our health, such as sleep disruptions. Proponents, on the other hand, frequently make the case for saving electricity because longer days require less artificial light. ,
“That was the original intent behind the implementation of daylight saving time. However, in our opinion, it makes sense to consider not only the impact on electricity savings in lighting, but also the overall energy consumption of a building” Sven Eggimann explains. Together with his colleague Massimo Fiorentini and other colleagues at Empa’s Urban Energy Systems Lab, he has therefore determined whether and how the time change affects heating and cooling energy consumption.
Our research shows that changing the time can help to protect the environment. In the debate over eliminating daylight-saving time, policymakers should consider not only the electricity savings from artificial lighting, but also the impact on the overall energy balance of office buildings.
Sven Eggimann
Going home earlier saves energy
The scientists hypothesized that because of the time change, employees start their work an hour earlier in the summer and leave the office an hour earlier in the afternoon. Because most cooling occurs later in the afternoon, this can save energy. The assumption is that in an empty office, cooling can be reduced or even turned off entirely. This would be relatively easy to achieve in the future as buildings become more intelligent.
To test the hypothesis, the researchers used data from various office buildings in 15 US cities to simulate the heating and cooling energy used with and without daylight-saving time for different climatic regions. They considered not only the current climate, but also future climate scenarios up to the year 2050 in order to include the influence of climate change. This is critical because climate change has a significant impact on the energy consumption of a building. In another study, Empa researchers discovered that, as a result of climate change, Switzerland’s demand for cooling may eventually equal that for heating.
The current study’s findings should please supporters of daylight saving time. “Switching to daylight savings time can save up to 6% on cooling energy in an office building. At the same time, due to the earlier start of work in the morning, heating demand may increase by up to 4.4 percent. However, because much more cooling energy is required in the summer than heating energy, the time change has a positive overall effect on a building’s energy balance “Massimo Fiorentini summarizes.
The overall energy savings varied across climate zones and scenarios, peaking at around 3%, but they were visible everywhere. Although this result only applies to office buildings in the United States, it provides valuable insights for Switzerland because the climatic conditions for several of the simulated climate zones are comparable.
Contribution to climate protection
“Our research shows that changing the time can help to protect the environment. In the debate over eliminating daylight-saving time, policymakers should consider not only the electricity savings from artificial lighting, but also the impact on the overall energy balance of office buildings “Eggimann explains. At the same time, the researchers emphasize that changing the time is only one of many factors that can affect a building’s energy consumption.
Building technical improvements, behavioral changes, and a general adjustment of our working hours can all contribute to energy savings and thus CO2 reduction – whether or not we change the time every six months.
However, it’s important to note that the energy savings from DST can vary depending on various factors such as location, climate, and behavior of the population. Some studies have even shown that the energy savings from DST may be negligible or even negative in some regions. Overall, while the energy savings from DST may not be significant, it is still a potential benefit of this practice.
