Abstract

The original rationale for adopting daylight saving time (DST) was energy savings. Modern research studies, however, question the magnitude and even direction of the effect of DST on electricity consumption. Representing the first meta-analysis in this literature, we collect 162 estimates from 44 studies and find that the mean reported estimate indicates slight electricity savings: 0.34% during the days when DST applies. The literature is not affected by publication bias, but the results vary systematically depending on the exact data and methodology applied. Using Bayesian model averaging we identify the most important factors driving the heterogeneity of the reported effects: data frequency, estimation technique (simulation vs. regression), and, importantly, the latitude of the country considered. Electricity savings are larger for countries farther away from the equator, while subtropical regions consume more energy because of DST.

Determinants of the reported DST effects
Fig: Determinants of the reported DST effects (blue color denotes a negative effect on savings)

Reference: Tomas Havranek, Dominik Herman, and Zuzana Irsova (2018), "Does Daylight Saving Save Electricity? A Meta-Analysis." Energy Journal 39(2), 35-61.

Read the paper

Headline result

Electricity savings from daylight saving time: the best-practice estimate is essentially zero, 0.01% savings, against a 0.34% simple average of reported estimates (savings during the days DST applies; the paper finds no publication bias in this literature, so this is a methodological correction), based on 162 estimates from 44 studies (Havranek et al. 2018, Energy Journal).

How to cite

Tomas Havranek, Dominik Herman, and Zuzana Irsova (2018), "Does Daylight Saving Save Electricity? A Meta-Analysis." Energy Journal 39(2), 35-61.

BibTeX 
@article{havranek2018dst,
  author  = {Tomas Havranek and Dominik Herman and Zuzana Irsova},
  title   = {Does Daylight Saving Save Electricity? A Meta-Analysis},
  journal = {Energy Journal},
  year    = {2018},
  doi     = {10.5547/01956574.39.2.thav},
}

Where this has been used

The Congressional Research Service has cited the paper in the report on daylight saving time it prepares for the US Congress since 2018, and still does in the July 2026 update: “Havranek et al. (2018) conducted a literature review and found that ‘electricity savings are larger for countries [or areas] farther away from the equator, while subtropical regions consume more electricity because of DST.’”

The European Parliamentary Research Service used it in the ex-post impact assessment of the EU summer-time directive written for the Parliament’s Legal Affairs Committee, calling it “a seemingly methodologically sound literature review of the available research” and reporting its finding that average savings from summer time amount to 0.34% of total energy consumption.

Der Standard reported the result in its coverage of the EU consultation in July 2018.