Heating: How warm and when?

I just read this explanation on Barbican Talk of how the "background" underfloor heating level is set in the Barbican.  The heating system is active from 1st October to the 30th April.

The temperature used is an average temperature not just of the previous night but also the previous day, and results in a computation being done (automatically) as to how much charge to put into the system. Where the temperature is just above 15C, then no charge goes in, because nominally the system was designed to provide "background heating" up to 15C in people's flats. If it is only slightly below 15C, this results in fairly insignificant amounts of charge going in (e.g. just half an hour all night), which does not accumulate any useful heat to discharge during the day. Floor pads really need to get several hours of charge to accumulate enough heat to warm a room.

As the temperature drops, as winter advances, many flats appear to end up with more charge than they need to achieve a comfortable temperature, and we see their occupiers rolling open the windows in the depths of winter, to cope.