Increasing greenhouse gas emissions threaten human health and the environment. In response, healthcare managers face significant challenges in balancing operational decisions about patient care with carbon mitigation targets. We explore a bottom-up modeling framework to aid in the decision-making for both carbon and cost in healthcare, using data from a case study in Cornwall, UK. A model was built and run for secondary healthcare, specifically outpatient clinics, theater lists, beds, and diagnostic facilities. Five scenarios were tested: business-as-usual; service expansion; site closure; water temperature reduction; and theater optimization. The estimated emissions from secondary healthcare in Cornwall ran to 5787 T CO(2)eq with patient travel adding 2215 T CO(2)eq. Closing selected sites would have reduced this by 4% (261 T CO(2)eq), a reduction less than the resulting increases in patient transport emissions. Reducing hot water temperatures by 5 °C and improving theater usage would lower the footprint by 0.7% (44 T CO(2)eq) and 0.08% (5 T CO(2)eq), respectively. We consider bottom-up models important tools in the process of estimating and modeling the carbon footprint of healthcare. For the carbon reduction targets of the healthcare sector to be met, the use of these bottom-up models in decision making and forward planning is pivotal.