Just to make sure humidity stays stable, humidity fluctuates quite a bit seasonally here and it would be nice to not have to constantly add or remove insulation and water bowls to make sure it stays right. That and most decent thermometers cost as much if not more than that Hygrometer, so I was just wondering if it was decent or not. And if I were to decide to go the arduino route, most of the sensors have both thermometers and hygrometers in them :-/

(*)http://www.sercc.com/climateinfo/historical/avgrh.html
and my apt. is below ground level... I've seen humidity as high as 80% inside to as low as 30% in winter... it was a pain when i was doing a research paper on the effects of humidity on radio signals :/