In January last year, Google agreed to buy Nest Labs, a start-up company making thermostats (and, more recently, smoke detectors) for $3.2 billion. It’s an astonishing amount of money, particularly for a business that was only started in 2010. The success of the Nest ‘smart’ thermostat was based on it replacing traditional central heating programmers, which consumers find difficult to set up and, more important perhaps, it’s ability to learn. The Nest thermostat is a beautifully designed circular control that learns the pattern of temperatures that you set over time. Within a few days, it programs itself to repeat the pattern.