Operational carbon is the term used to describe emissions that are associated with the “operations” of a building, specifically the energy used to power, heat, cool, and ventilate a building and the water consumed during a building’s life cycle for heating, filtration, or sewer processing. Operational carbon makes up 28 percent of total global greenhouse gas emissions, which presents a massive opportunity for decision-makers to implement codes to tackle these emissions. However, the United States currently does not have any model energy codes with provisions directly related to operational carbon. This means that new homes and buildings constructed today can operate for years without the need to reduce emissions over time. This lack of oversight creates further complications that will hinder solving the climate crisis. Model energy codes must take into consideration these concerns and directly address operational carbon.