DIAGNOSIS The capacitive touch layer is malfunctioning. This can be caused by a software glitch, a faulty screen, or static electricity.
FIX Perform a hard reset. Press and hold the Menu button for 10-15 seconds until the screen goes blank and the Emerson logo reappears. This reboots the system without erasing your schedule or Wi-Fi settings. Test the screen responsiveness.
IF THAT DIDN'T WORK A persistent screen protector or a buildup of static charge can interfere. Remove any aftermarket screen protector. Power down your HVAC system at the breaker, remove the thermostat, and briefly touch the metal terminals on the back to discharge any static. Reinstall.
HEADS UP If the lag is worst in very dry conditions, it is likely static-related. Using a humidifier can help. If the problem persists after a reset, the touch digitizer may be defective and require service.