The environmental footprint of the Swiss consumed electricity is not constant over the year. Indeed, the share of the energy production means varies throughout the days, weeks and months, as a function of the electricity demand, resource availability (hydro, solar) and the power plant availability (maintenance). Switzerland also balances its electricity grid with imports from neighboring countries. All these possible fluctuations imply a variable environmental footprint of the Swiss consumed electricity, which affect the environmental impact of the building electricity demand. So far, in Switzerland, the environmental accounting of the building energy demand considers yearly average impacts for the consumed electricity. The EcoDynBat project has developed a framework to collect and merge all the necessary data to conduct a Dynamic Life Cycle Assessment (DLCA) of the environmental impact for the Swiss building consumed electricity under different time steps. The resulting database and methodology has been applied to different profiles of building electricity demand, including buildings with heat pump and/or decentralized electricity production systems. The study evaluates the influence of different time step resolutions on the environmental impacts of the electricity demand in Swiss buildings. Results for the climate change impact show a variability going from 36 to 580 g of CO2 eq/kWh for the consumed electricity when using an hourly resolution, during a one year period. This variability causes an increase in the impacts of up to 24% for space heating, when compared to the annual average impacts. Other electricity loads that do not have a seasonal profile are less affected by the time resolution. Nevertheless, observed trends suggest that an hourly resolution will be relevant to evaluate the potential environmental impacts of smart buildings.