unknown user wrote:

Just curious, are you a high school student that happen to be doing
a science project on this subject?

Possibly. Are you a nubile senior with similar interests? :-)

...some "proper software" for an $8 Casio FX-260 calculator: ventilate
when RoRie^(9621(1/(460+To)-1/(460+Ti)), ie RoRie^(9621(1/(460+To)-1/530)
if it's 70 F indoors. For example, if it's 70 F with 80% RH indoors and
80 F outdoors, ventilate when Ro0.8e^-0.336 = 0.57, ie the outdoor RH
on the $20 Radio Shack display is less than 57%...

That's a Clausius-Clapeyron approximation.

Nick