Is it really a problem? An ESP8266 (which is not the most efficient thing, but is very cheap) uses about 0.5W while transmitting, much less most of the time.
For reference, I have some smart outlets that I measured using a while ago, pulling about 0.05W on average from the wall, or 36Wh a month. That's about as much energy as making 500ml of coffee or charging a phone 2-3x.
not sure if its a problem in reality, radios are the second most power consuming subsystem of my laptop at idle. (first being screen due to the backlight).
For reference, I have some smart outlets that I measured using a while ago, pulling about 0.05W on average from the wall, or 36Wh a month. That's about as much energy as making 500ml of coffee or charging a phone 2-3x.