I have decided, as a arrogant geek, to build my own home ventilation and heating system, and will try to do this as my little project. I have always been annoyed with the lack of good ventilation systems at work, so I accept building my own is arrogant.

Does anyone know about a device I can interact with that allows me to get temperature and humidity that I can interact with using C#?

I cannot get it from the Internet because I need to get the humidity from my server "room", so I can control the dehumidifier there. Similar with temperature, outside is not that important. It would be a huge plus if the sensors had some sort of wireless access.