First off do you mean digital thermometers? A thermometer tells you the temperature, a thermostat is something you hook up to a heating source to controls the heat it outputs.
I知 not sure what you mean by air vent but I知 guessing it痴 a thermometer with no probe, which is very inaccurate as its just measuring the air temp. If I知 wrong and just not getting what kind of thermometer you are using please post a picture. You are going to want a thermometer with a probe and have that probe contacting the surface of what you are trying to get the temperature of. Even with those though they have a margin of error and will only give you an approximant temperature. For a accurate temperature reading you need a inferred thermometer. Something like this: http://tempgun.com/products/pe1/

For the humidiy you can try sealing up a few of the holes you made, adding a bigger waterbowl or adding a humity hide (a hide with moist Sphagnum moss)