Carbon footprint of your building is growing in importance each day. Calculating and optimizing your building carbon footprint makes for better investments in construction projects, helps win new clients and is demanded by regulators and certification schemes. Life-Cycle Assessment — LCA — acts the industry standard methodology in quantifying the CO2 footprint of a building. Building carbon footprint is the total amount of greenhouse gases produced throughout the life-cycle of a building, both from energy use and via materials. Building CO2 includes the carbon emissions from all life-cycle stages such as material manufacturing (i.e. embodied carbon, capital carbon), and operating emissions (e.g. operational carbon). Carbon footprint can also be used to track yearly operational emissions of a building. One Click LCA offers ready-to-use tools for both cases as well as life cycle costing (LCC). Why is Building CO2 an important impact category? Greenhouse gas emissions are a key environmental metric and an integral component of building life-cycle assessment (LCA). Mostly, it is the most widespread and generally understood indicator of environmental impact and climate change. Building carbon footprint is used in all green building certification schemes, in LEED it can contribute up to 5 credits and in BREEAM up to 9. CO2 is the single most understandable environmental impact category globally.