Product review (5 stars): Perfect Indicator
Purchased this instrument to monitor the humidity in our closets and walk-in closet in our home.  Some of the rooms within our house have more mildew than others.  Took comparison readings of the different rooms and closets.  Tried the heating rods in the closets to determine whether these rods help in lowering the relative humidity.  Tried running the central A/C system on DRY mode in one of the bedrooms to see whether the A/C works in lowering the RH (relative humidity) and it does.  Love the large digital readout and simplicity of use.  Moved the instrument among the closets in different rooms of the house to get an idea of the humidity in these areas and to confirm the likelihood and severity of moisture, possibility of mildew development.
It's only been about a week of using this meter, but I think it is essential in attempting to control the RH and mildew within your home.  Concerned about the electrical consumption of whatever mildew device I utilize, so trying various other processes to see if these work before resorting to a dehumidifier.  The hanging Damp Rid fragance free collects a lot of liquid in its pouch, but the RH in the closet has not decreased noticeably at all.  The heating rods do not lower the RH quickly and I may need to give this more time.  If you want to systematically work towards getting rid of your mildew/mold problems, you should seriously consider getting this instrument.