The Life Cycle Assesment LCA is a method used to quantify the environmental impact of a product or service along their life cycle. The tool offered is based on the LCA and will provide an easier and a visual comparative report to assess the impacts generated by two different facade's construction solutions. The source of the results are feed from a database composed of data from the Environmental Product Declaration which is a mechanism used for environmental communication. The Environmental Product Declaration is the most prestigious and well recognized mechanism due to the objectivity incurred on the data collection process. The tool enables selecting various facade's configurations through the combination of different layers. It was decided not to evaluate the actual environmental impacts with the aim of building a decision making tool where the technician will be able to go in depth for the specific impact of each material and identify and approach the important focal points using the comparative report. The LCA simplified tools represent a compromise for a precise evaluation, but it will be necessary to be realistic and transparent about their limits as stated at the end of the paper. Enviromental impacts, Sustainability, Life cycle assessment, Building assessment tools, Façade comparative assessment INTRODUCTIONL a industria de la construcción es una de las que más recursos naturales emplea, tanto renovables como no renovables. Se estima que el 41% del consumo de energía y el 35% de las emisiones de gases son debidos a las edificaciones, solo en Europa. La UE, comprometida con los objetivos fijados en el Protocolo de Kioto, debe lograr reducir las emisiones de gases de efecto invernadero en al menos un 50% para el año 2050 [1].Es imprescindible que la construcción llegue a ser sostenible. Se ha avanzado en materia de gestión de residuos y conservación de la energía, ya reconocidos en la normativa  It is based on LCA with database composed of EPD. Appropriate to assess building systems. Use of BIM tools in the construction stage is minor. There is a development of limits that this tool is facing.C. Jiménez-Gámez, "Enviromental impact comparative tool based on life cycle assesment".