3.  Could your mask leaking significantly?

If you know that you filled the chamber the night before, check the humidifier setting.  On some machine models this can be changed accidentally.  So, if complete water evaporation is a new problem, make sure you haven't inadvertently increased the setting. 

When a mask leaks excessively, water from the humidifier evaporates quickly.  It is very common to not even be aware that one's mask is leaking this much!  If you are unsure about your mask fit and you do not have a bed partner complaining that you are making too much noise at night, consider having your machine data downloaded.  Of course, not all machines record mask leak.  In that case, schedule a fitting with your local CPAP equipment provider.

Many people report just the opposite--it seems that no water is being used and they wake feeling very dry.  Again, the setting may have been changed accidentally.  The lower the setting, the less water that will be used up.  Another factor to consider is the humidity level of the room in which you are sleeping.  Dry environments will use more water, humid environments less.  If neither the setting on your machine has changed nor the environmental humidity, you will need to make sure your humidifier is actually heating the water.  You can check this by turning on the machine and turning up the humidifier setting while placing your hand on the metal plate at the bottom.  If you do not feel the metal getting warmer, your humidifier may be broken.

Please feel free to give us a call if you are having any trouble with your machine, humidifier, or mask!