Essential Mode is available in the Embr Wave app starting May 9, 2019. If you have automatic updates enabled on your phone, you should see the latest version the next time you open up the app! If you don't have automatic updates enabled, find Embr Wave on the App Store or Google Play Store and get the update there.
To use Essential Mode: Just tap the Modes button on the bottom of the main screen and select Essential Mode for cooling or warming.