Background: To minimize the risk of perioperative hypothermia, it is recommended that healthcare professionals be familiar with heat conservation measures and use passive and active warming methods, in line with international guidelines. However, there is a low level of adherence perioperatively to the use of heat conservation measures. To understand why, there is a need to capture the nurse anesthetists’ perspective. The aim is to describe nurse anesthetists’ perceptions of heat conservation measures in connection with surgery. Methods: An inductive descriptive design with a phenomenographic approach was chosen. A total of 19 nurse anesthetists participated and were interviewed. Data were analyzed according to Larsson and Holmström’s phenomenographic seven-step model. Results: Six ways of understanding the phenomenon heat conservation measures in connection with surgery were found: the preventive, the useable, the untenable, the caring, the adaptive, and the routine care approach. These approaches were related to each other in a flexible way, allowing for several to co-exist at the same time, depending on the situation. Conclusions: Nurse anesthetists want to prevent the patients’ heat loss and maintain normothermia, regardless of the type of surgery. This willingness, motivation, and intention enable the use of heat conservation measures. However, there are perceptions that have an impact, such as doubts and uncertainty, access, time and financial constraints, preconditions, routines or habits, and lack of availability of education/training. These barriers will require support from an organizational level to promote lifelong education and guidelines. As well as offer education at the nurse anesthetists’ program.