Alternative solution in case money doesn't matter that much and in case you already have 1-wire environment installed: google for "OW-ENV-THPL"
There are multiple sensors available, with THPL being the one who has the most sensors (i.e. Temperature, humidity, barometric pressure, light intensity (lux)). There are other sensors available with only T + Rh which cost less.
Yes, those sensors aren't exactly cheap, but installation and readout is quite easy.
One more drawback regarding 1-wire: owfs in combination with a DS9490R busmaster is quite unstable, so you have to take care of this instability in your readout scripts.