By Chris Baraniuk Imagine a building that tells you – before it happens – that the heating is about to fail. Some companies are using machine learning to do just that. It’s called predictive maintenance. Software firm CGnal, based in Milan, Italy, recently analysed a year’s worth of data from the heating and ventilation units in an Italian hospital. Sensors are now commonly built into heating, ventilation and air conditioning units, and the team had records such as temperature, humidity and electricity use, relating to appliances in operating theatres and first aid rooms as well as corridors. They trained a machine learning algorithm on data from the first half of 2015, looking for differences in the readings of similar appliances. They then tested it on data from the second half of the year – could it predict faults before they happened? The system predicted 76 out of 124 real faults, including 41 out of 44 where an appliance’s temperature rose above tolerable levels, with a f...