Out of interest, do you know how that was calculated? Obviously that's crazy regardless but is that over the course of a year with the aga being left on for half of it or just over the period of time that a regular oven would be used?
Dunno. I found it on Wikipedia.
ETA the consumption stats are pretty outrageous.
In a week an Aga will consume as much gas as a conventional cooker would in 9 months.
Just been nosing around on the interwebs. The energy consumption of a conventional oven and hob is 2.6% of that of an Aga. Which was an eye-opener.