OK I have put a 25 watt bulb in the bator. Last night, I turned the light and fan on. I took all air plugs out(there are 2), and I didn't add any water, just to see how low hum. goes without water. I stuck the temp. probe in my homemade water wiggler(plastic snack bag with water in it) and temp. climbed steadily from 60*F. to about 95*F in a few hours. Hum. went down to like 20% so I added water in the bowl and it went slowly back up to about 30-40% But then i had to go to bed, so I shut it off. I never saw what the max. temperature or hum. was, but I will test it again! How's it sound so far???