Hi @speadie and @raym64 ,
thank you for the suggestions. You are right about the fact that many traditional thermostats simply give the control of fan to the furnace control board. However, there are more than hundreds of different control boards under different brands with different control logic. Some systems have layers of safety valves and sensors, and some systems do not have, many of our customers are getting the new thermostat to have better control of the old system. Without independent control of the fan and the furnace, our customers may have a very different experience with the same product caused by different HVAC boards. Some advanced features like turn off the AC earlier and use the remaining cooling or heating, or fan operation for ventilation purposes will be impossible if we give up the G wire control. We are actively collecting user feedback to improve the product experience. I feel like the solution could be giving the user the option to leave the fan to the furnace as an advanced setting