Many studies have been conducted to detect and attempt to mitigate the collateral harm caused by the building sector, with a primary focus on the usage stage for greater energy efficiency. It has become clear, nonetheless, that research must concentrate on the whole life cycle of buildings. In this paper, life cycle assessment for 9 different wall systems that are commonly used in Hungary is carried out to compare their environmental impact. The contribution of the life cycle stages and materials to the carbon footprint is assessed in absolute and relative terms. We also explain the reasons behind these differences and relating them to the natural characteristics of these materials. Calculations show that the stage with the highest contribution is the production (A1–A3), reaching 88% for reinforced concrete while it ranges for other walls from 16.5% to 83.7%. The wall with the highest carbon footprint was reinforced concrete and aerated concrete wall (with 123.3 CO2-eq and 94.9 CO2-eq respectively). By addressing the methodologies in the analysis, we can offer more in-depth information about how well building materials (like concrete, steel, and timber …etc.) perform.