 The European Green Deal emphasizes the need to drastically reduce excessive carbon emissions from buildings, which are a major source of global warming. The design phase of a building accounts for over 80% of its product-related environmental impacts, highlighting the urgent need to explore low-carbon measures in building design. This paper uses linear regression reverse engineering and percentage calculation to identify that a GWP of minus 30.000 CO2EQ or lower, around minus 165 CO2EQ slash M2, in 25% of a block of houses can lead to carbon reductions by 11%. However, the paper identifies barriers related to databases needed to achieve this task. This article was authored by Luis Berganca and Maria Concepción Verde Muneza.