This study investigates how to effectively reduce the climate impact of concrete in the construction process. To reduce COշ emissions and high cement usage, several methods have previously been introduced in today's construction industry, such as changes in concrete composition and the development of greener concrete, also known as climate-improved concrete. An innovative solution to further reduce cement consumption and thereby COշ emissions is a nuanced use of exposure classes in concrete structures. The method is based on using the right concrete in the right place with an increased differentiation of strength classes. Using the right concrete in the right place means not using a higher concrete quality than necessary. The choice of concrete quality is governed by several factors, where exposure class and strength requirements are central. The exposure class determines a maximum water-cement ratio (w/c) that should not be exceeded within the given exposure environment, and the selected w/c results in a specific concrete quality. The theory is based on the assumption that higher concrete quality than necessary is often used in construction projects, even though the exposure class would allow for a lower concrete quality. If this assumption is correct, there are significant opportunities for improvements in sustainability, both from an ecological and economic perspective. Higher concrete quality involves increased cement consumption in the concrete mix, which leads to a greater climate impact from the concrete. The production of cement accounts for about 90-95% of the carbon dioxide emissions from the use of concrete, which is why reducing material consumption as much as possible is desired. By optimizing concrete usage with a more nuanced differentiation of concrete qualities, significant reductions in carbon dioxide emissions can be achieved, while cost savings can also be made since concrete with lower strength classes is generally cheaper to procure. The results from the investigation of a multi-family house constructed project by Sweco commissioned by Skanska, prove that the method is effective. A reduction of approximately 16-17% in carbon dioxide emissions from the concrete in interior walls and internal basement walls, as well as a reduction of about 3-4% in material costs for concrete and 7% for reinforcement, was achieved. Interviews with various constructional operators have shown that it is possible to apply this method in future projects with well thought out planning and understanding to avoid any wrong orders and delays.