Does such a device exist - boiler monitor

[Torquey]

I'd quite like to know how often by combi boiler fires up for central heating purposes.

If I have my thermostat set to 16 degrees 9am - 5pm I'd like to know how often and for long the boiler is in action for during that time. Likewise - I'd like to know how long the boiler has to work to get the house from 16 degrees up to 20 degrees on an evening.

I thought about some kind of USB/RS232 thermometer attached to a radiator and a laptop to take a reading every 5 minutes, then plot it on a graph in excel! I'm surprised there's nothing more simple though.

I know theres not many benefits to this except maybe showing how well insulated your house but it would satisfy my curiosity. Does such an item exist? Maybe I'm not searching for the right term!

[Torquey]

Thanks for this. I didn't expect a Nest to do this. I was thinking of getting a Nest or Hive in the near of future but this might hurry me along now.