I've worked at my current job (a .com) since February 2000 and we had a small telephone room on the corner of the building also used as a server room. This room had a window and management decided to placed a window unit in. It was about October when the unit would freeze up because of humidity. We got a dehumidifier and this solved the freezing up of the window unit but we had a new problem around December. The window unit wouldn't turn the compressor on due to some internal thermostat that makes it think that it doesn't need to cool. We then decided to buy a window unit with the digital display on the front. This worked but any type of small brown out or power blip would cause the unit to turn off. Since this had a digital on/off the unit would not come back on. Then we got a Falcon to monitor the temperature in the room and if it gets above 85 it would text message our cell phones. (The can be done via email.) About a year ago we moved to a new office and in the server room is a Liebert AC with the optional dehumidifier.

We also use an external service http://www.alertra.com/ to check our web servers to see if they are responding to http requests. We also use this service to check and see if the power goes out by pinging a box that doesn't turn back on when the power fails. We can have power go out for less than a second for no damn reason. If any of these fail it will also send a text message to our cell phones.

If you would like to know more we could talk over the phone. PM if you would like my phone number.