I also suggested that Colin add a humidifier in that room. If the RH was 20% in here, my nose would be bleeding and I'd need a gallon of water a day. That's cause of all the holes I have in me.
Thing is, the greater the difference in RH on the outside and inside of the humidor, the greater the vapor pressure differential.
Vapor pressure is odd in that it isn't a direct relationship. You can't math it with a formula, you need a chart.
The greater the differential in vapor pressure, the greater is the force at which your humidor will expel water vapor.
You'd think it'd be the same across the board, but it's not at all.
Think of it this way...
If the RH inside a mayonaisse jar is 72% and the RH outside is 73%, the vapor pressure variance will be very slight, so the water vapor in the jar will move out and mix with the surrounding air calmly and slowly when the lid is removed.
If The RH in a humidor is 72% and the room RH is 20%, the vapor will rush out of the humidor with a force much like air runs out of a balloon when you let it go.
Realistically, even in the type of situation Colin has, a nice, tight humidor (no leaks) should lose a couple ounces of water each winter season if you open it twice a day.
That figure is generous, I did the math till I was blue in the face when I developed HCM beads.
Obviously, a few leaks are to be expected.
But if a guy is cranking out a quart of water a week, there's a HUGE problem. Math and RH/temperature/pressure relationships bear it out very obviously.
It's why it's so easy to help guys figure out what's going on.
Math + Nature = You got a leak. Period.
