Personal experience. I have a ResMed AirSense 10 with the 90 watt brick, 1-1.5 Amp input at 115 volts with 3.75 amp output at 24 volts.
I run the unit through a ProWatt 2000 inverter and use the humidifier every night.
Average use is 7 hours per night. Battery bank drop per night is about 22 Ah. This includes inverter and conversion losses.
Not a big power hog in my book. Easily made up by the solar power system.
Yes, I could buy a 12 - 24 booster, turn off the humidifier and save 10 or 12 Ah per night, but at this point no need.