My digital thermostat also measures humidity. After I sprayed last night, it jumped to 99% LOL. I checked it this morning after it had time to settle, and it was still around 70%, but I'm just not sure how accurate my humidity reader is. I'm going to cover the lid with a piece of cardboard with foil over it. I plan on cutting a hole about 1/2" wider than the CHE so it can still do its thing and cut holes on each side for air flow and see how that works out once I get my thermostat installed. I will post pictures of this "marvel of engineering" once I get it made ;P