BathroomExhaust fans run continously?
I suppose it's at least half an answer, so moving from comments:
If the fans are wired to run that way your house may well be built to a high standard of air-sealing, and the fans running (possibly with a heat recovery ventilator involved) may be an important part of maintaining good indoor air quality - at which point the power to run them is not a &quot;waste&quot; and the heat/cold required to adjust the air they replace is far less than that required in an older house with random air leaks.
In that case, turning them off may cause major indoor air quality problems.
The above is the only case I'm aware of where bathroom fans are set to run continuously as a deliberate design part of the HVAC.
A mechanical vetilation requirement evidently was integrated into IRC circa 2012
As for the other half of the question, the linked document notes a minimum efficency for bathroom fans of 2.8 cfm/watt and a maximum ventilation rate for them of 90 cfm, leading to a maximum power draw (per fan) of 32 watts, or roughly 282 kwh/year. Or it could be as low as 31 kwh/year for the minimum sized bathroom fan (10 cfm) or even lower if the fan is more efficient than the minimum required efficiency.