The short answer: Yes, this can be calculated, but it is complicated. Your BEST BET is to go with how the room feels to you. So, how does the room feel??? If the room feels stuffy or the walls are damp, the humidity is probably too high. 60% or higher is problematic of mold issues and uncomfortable. Or, 40% or lower is problematic - being too dry causing static discharge (bad for your PC), dry skin, and cracks in wooden objects (furniture, etc.)
That said, you might see what electronic gizmo is on the market at Radio Shack, for one. You will want a device that can measure relative humidity. Preferably, it should give you dry bulb temperature (i.e.: the temp we can feel and readily understand). If not too expensive, it wouldn’t hurt if it could measure wet bulb temperature, as well. (FYI: This device may be marketed as a digital hygrometer.)
Ok, now if you STILL want to calculate the actual flowrate of moisture off the dehumifier, this can be done BUT first: (a) You’d have a bigger challenge. Can you measure the airflow across the dehumidifier? I understand Radio Shack sells a hand-held anemometer, but I don’t know how accurately it can measure low wind speeds. Or, you might have to rig up a child’s pinwheel toy to take some empirical airflow data and convert to cfm, preferably. (However, a child’s pin wheel toy may offer too much resistance to turning at low flows. Try applying some petroleum jelly to the axle with a cotton swab, if possible.)
(b) Next, you need to measure both the dry bulb and wet bulb temperatures of the room you are trying to dehumidify.
© You’d have to learn how to read a psychrometric chart. Also, you need to understand the difference between relative humidity (%RH) and specific (i.e. an absolute measure of) humidity. FYI: The latter is sometimes called the humdity ratio. Often, this value is expressed in units of lbs moisture/lb dry air. But, ot can also be expressed as grains of moisture/lb dry air. To convert from grains of moisture to lbs of moisture, divide grains by 7000. (Yes, specific humidity is a small number when expressed in lbs moisture…hence, grains is a more convenient unit, at times.)
To learn this, you’ll have to consult either a thermodynamics book, mechanical engineer’s handbook, or HVAC handbook. Look for a book that gives examples with graphics to supplement the text since the psychrometric chart can be tricky to read correctly.
Hope this gives you some food for thought! - Jinx
