The paper introduces a newly designed dynamic building energy simulation screening tool to help integrate the use of advanced simulation techniques to early stage building design and feasibility studies. The tool will help the design process to move toward an integrated design approach, including energy analyses and expertise from the first stages of design when time constraints and information requirements are still a hindrance for the use of other existing simulation tools. The paper focuses on the integration of the user input and output interfaces and automatic model generation algorithms while referring to previously existing papers in term of model definition, case studies and validation. The tool is able to simulate building energy performances starting from a limited number of inputs received through a specifically designed user interface supported by databases and suggested values. Based on those inputs, a simplified building model is generated and simulated in EnergyPlus and results are post processed and visualized on the user interface. The tool is fully web based and can be used through any web-enabled device as only the input and output interfaces are managed by the user device, with all other components being allocated to the server. The tool is able to run building performance simulations based on a simplified building model description with a limited number of inputs and in a short span of time, ranging from minutes to less than an hour. Nonetheless, the simulations are still returning results with an acceptable margin of accuracy compared to a detailed simulation, considered to generate useful information during early stage design and still higher compared to the use of traditional stationary models. The proposed tool will help the design process evolve toward an integrated approach and adapt to the foreseeable changes in regulations and market demand of low- And zerocarbon buildings.