It is recommended to preheat the infrared sauna before use to shorten the time it takes to start sweating and experience the therapeutic effects. The warm-up time varies depending on the size of the space inside the sauna and the outdoor temperature. The warm-up time in a small sauna is relatively short, about 10 minutes. On the contrary, when the sauna is larger, the warm-up time is slightly longer, about 15-20 minutes. In addition, when the ambient temperature is low in the winter, the sauna may take longer to warm up because it needs to overcome the lower ambient temperature. This will require an additional 5-10 minutes to warm up the sauna than on a warm summer day.