You will rely less on radiators
At full cooking temperature, a programmable AGA heat-storage cooker radiates up to 1.5kW per hour and up to 1kW per hour in slumber mode. This energy usage is very similar to a medium sized household radiator, which emits up to 1.5kW per hour.
This means that an AGA cooker gives off enough heat to keep most kitchens warm, even in winter, which means you're likely to never use the radiators in that room. This will compensate for the energy an AGA uses and could even save you even more.
There are also a number of ways to potentially link an AGA cooker's warmth into natural airflows in the home. Some owners link up their heat-storage cooker to a heat recovery system to make use of the residual heat. This shows you that AGA has the capacity to be central to new home energy management systems.