Hlipka wrote a post on his blog detailing his continuous temperature monitoring build:
Two years ago, when we returned from our skiing vacation, there was a nasty surprise waiting for us: with outside temperatures of down to -20° (celsius), our heating system had shut down. At one point, the pilot flame went out, and without it the heater could switch on again. I don’t know the reason for that (and it hasn’t happened since then), maybe there was a drop in gas pressure. Fortunately the temperatures were not so low for the vacation of last year, but for this year I decided I would like to be able to handle this problem.
Since I cannot really alert the service technican automatically (maybe I could, but he wouldn’t get into the house anyway), I want to know at least that there is some kind of a problem. Some I need some kind of temperature monitoring.