The last thing we want as a business is for anyone to convert their cooker and then be disappointed so I thought I'd keep a note here of the drawbacks I have noted in the past and any that come up from customers over time. Lets get started, its not a huge list thankfully!
The main one that I always note is the power cut issue. If you are very rural and suffer extended power cuts regularly then an 'Electrikit' converted cooker may not be for you. The ovens, being super well insulated, will stay hot for several hours in the event of a power cut but the hotplates will cool down quickly and if you are without power for more than a few hours then you'll be eating salads! You can run the cooker from a generator if you have that capability. The ovens draw 1.8kw with the hotplates a further 1.4kw each so you don't need a generator the size of Wales or anything!
The 'wasted' heat issue. Converted Agas do give out less heat than many traditional cookers. Technically this is a feature not a bug as heating a room with an Aga is the most expensive way imaginable to do it (short of burning £20 notes in your wood burner!) so just turn on the kitchen radiator or get one installed to compensate and save a fortune! Converted Agas are still very warm to lean against and dry washing on - you just won't heat a barn with one like some old traditional cookers!
The 'why won't my marmalade boil' issue. This is a very recent one that has come up in the last few days and it comes down to this. The hotplates use a combination of heat storage (they are big pieces of metal) and an electric element below to respond to heat loss. If you pop your enormous marmalade pan on the hob it will 'use' the stored heat quite quickly and then the element will kick in to do its job. At 1.4kw though its just not big enough to directly heat a huge quantity of thick marmalade above unless the lid is on. In this case you will need to make the marmalade in smaller batches (normal size pans). Our conversions share this issue with the recent smaller TC electric cookers. [Update... A recent conversion customer has reported that marmalade works perfectly in a 14 litre stockpot from John Lewis. The key would appear to be pans with very flat bases - this goes for all Aga range cookers to be honest!]