At a site examining living in a sealed environment, they stated the
average person exhales and perspires approx. 4 1/2 gallons of water per
day.

I don't think so. That would mean that you have to drive 4.5 gallons
per day. Even in the desert, I only drink 1 gallon per day at the
very most. I believe the 4.5, but the units have got to be wrong.