Econ mode, or Energy Saver mode, is a setting that works similar to central AC. The room air conditioner will turn off once the set temp is reached; the fan then cycles on (for 20 sec.) every 10 min to sample the air temp. If the room temp is above the set temp, the compressor will turn back on.
Is Eco mode bad for AC?
Eco mode runs the compressor at a slower rate. The motor uses less energy when the pressure in the condenser is reduced. The reduction in overall cooling capacity is offset by the increase in efficiency. You can use less power by changing the compressor speed.