Older versions of the Ecostrad Accent iQ beep after turning on, beep twice to signal the infrared panel is ready to pair with sensor and then beeps to confirm connection to sensor. This heater also beeps when commands are sent from the app, including when adjusting temperatures, setting timers, and turning on/off.
The thermostat clicks but otherwise the heater is silent. There are no expansion noises, except for a short while after first use.
Newer versions are the same except there is only one beep after the panel turns on.