The issue of environmental sustainability is increasingly topical and one of the most impactful sectors is that of the construction industry. As stated in the reports of the GlobalABC, the building sector is the main responsible for GHG emissions, generating about 37% of global CO2e emissions. Already during the phases of production and construction of buildings about 10% of global emissions are produced, while the remaining part comes from their use, from the energy for air conditioning and lighting. Reducing emissions in the pre-use phase of buildings is therefore a crucial issue for combating climate change. The research investigates the potential of timber construction systems, thanks to the carbon storage property of the material. The proposed calculation methodology is structured according to the LCA-Life Cycle Assessment approach, referring to the C2H phase (from Cradle-To-Handover), and evaluates emissions related to the production and construction of buildings. To identify the timber construction system that minimizes CO2e emissions, within the limits of the investigation (A1-A5 phases), the method was applied to two buildings built with different technologies: one with X-Lam panels and one with a framed structure. The results were analyzed, compared, and discussed to demonstrate that the timber buildings are the most virtuous solution in the Net Zero Carbon perspective by 2050.