Nasal vs. Full Face water usage

I'm interested in whether there is a substantial difference in water usage based on what kind of mask a patient uses. My sister uses the same machine as I and we both use nasal pillows, yet uses 4 times as much water. She links a standalone humidifier downstream of her CPAP and still runs out of water in 6 hours. I know part of it is personal comfort level, but I'm wondering if it might be due to mouth leaks. I hope to get her set up with SleepyHead over Thanksgiving, but I'm trying to get a step ahead in what I might be looking for.

If you have watched your leaks, as you change from a full face mask to a nasal mask or pillows, I'd be interested in your observations!!

Thanks!!

KW

I'd say it sounds like mouth leaking/breathing. Same thing happens to me on nights when I blow out my mouth tape - I use up nearly all the water in the tank. On normal days, I only go through a tiny fraction of the water even when the humidifier heater is on and the air is dry.

When I use a FFM, I usually don't go through more water compared to the nasal mask, unless my jaw falls open. And for mouth breathing with the FFM, the pap-cap helps keep my trap shut. I do tend to get more leaks in general with FFMs, but that's probably because I have a slightly receding jaw, so the bottom part of the masks tend to leak more. The pap-cap helps with the leaking too, but not on all masks (e.g. I couldn't get the UMFF or the Quattro to work for the life of me, but the Quattro FX has been working well).

Lately I've started mouth-taping while wearing a FFM. Strange, I know, but it works.

What machine is she using? What is her pressure setting? What type of stand alone humidifier is she using?
Excessive leaks will use more water as well as higher pressures used will consume greater amounts of water even if leaks aren't a factor.