App: Switching between Fahrenheit and Celsius You can switch between Fahrenheit and Celsius using the settings icon on the Ember mobile app. Related articles App: Updating your Ember Ember Mug: What is the Charging Coaster Voltage? Travel mug: Can I use it without pairing to a phone? Travel mug: Can my Ember be used to warm up drinks from room temperature? Travel mug: Will it keep my drink cold too?