Low Cost and Effective Battery Operated Humidity Monitor

With the ever temperate temperature of the SF Bay Area, I've never been concerned with dealing with high humidity. Since moving into our home a few years ago and successfully removing several inches of water in the low dirt crawlspace, I wanted to know if having a vapor barrier installed in crawlspace would benefit both structure and health of the house. Before calling a few contractors for crawlspace quotes, I wanted a baseline of the humidity and temperature of the house. From what I read online, you want the humidity to be less than 60% to reduce the chance of living with mold and mildew.

I found on Amazon a highly rated and simple ThermoPro branded humidity monitor. I've previously purchased a ThermoPro meat thermometer which I used to perfectly roast a Prime Rib, so I trusted the brand. The device is well built and easy to use. I ended up purchasing the ThermoPro TP49 Digital Hygrometer. By placing it around different rooms of the house, I got great baseline numbers, which I snapped a smartphone photo which registers the room (via the photo background), time (via the photo metadata), and temperature and humidity (via Photo of the ThermoPro).

Below are some of my notes of the ThermoPro TP49 in no particular order:

• The numbers are large and easy to read.
• Low cost, only $8.
• Requires one included AAA battery, which is suppose to last 18 months.
• There is no backlight, but that's okay since it's only used indoors.
• Love the ability to hang on the wall, table top stand with stable legs, or magnetic back (to the fridge).
• One button on the back to toggle between Fahrenheit and Celsius.
• It's not inter-connected, but I don't need that for my needs.
• There are three faces which indicate "Dry", "Comfort", "Wet".

Easy Ready Faces:

• Dry: < 30% humidity and any temperature
• Comfort: Between 30% - 60% humidity AND between 68 - 79 degrees Fahrenheit 
• Wet: >60% humidity and any temperature
• No face: Between 30% - 60% humidity AND NOT between 68 - 79 degrees Fahrenheit 

Improvement Suggestions:

• I wish they printed the conditions for the three faces on the back cover (it is published in the paper manual, but that's going to be thrown away). I ended up writing mine in with a sharpie.
• I wish the faces are clearer. Both the "Dry" and "Wet" faces look similar with a horizontal line for the mouth
• I wish the "Comfort" could be utilized between a wider temperature range. Even if the humidity is between 30% and 60%, if the temperature isn't between 68 - 79 degree Fahrenheit, no icon is shown. I rarely set my thermostat to 68 degree Fahrenheit.

Note, if you are interested in larger monitors which can communicate additional data points from both indoor and outdoor (wirelessly connected monitors), this is not the ideal product. For my personal needs, I didn't need all the other data points for my project.