Understanding how populations’ daily behaviors change during the COVID-19 pandemic is critical to evaluating and adapting public health interventions. Here, we use residential electricity consumption data to unravel behavioral changes within citizens’ homes in this period. Based on smart energy meter data from 10,246 households in Singapore, we find strong correlations between the pandemic progression in the city-state and the residential electricity consumption. In particular, we find that the daily new COVID-19 cases constitute the most dominant influencing factor on the electricity demand in the early stages of the pandemic, before a lockdown. However, this influence wanes once the lockdown is implemented, signifying the arrival of a ‘new normal’ in the residents’ lifestyles. These observations point to a proactive response from Singaporean residents---who increasingly stayed at home during evenings despite not being forced by the government to do so using a lockdown---a finding that surprisingly extends across all demographics. Overall, our study enables policymakers to close the loop by utilizing residential electricity usage as a measure of community response during unprecedented and disruptive events such as a pandemic.