Well first of all if it’s going to have more than 30 square meters of floor area then you could be looking at needing planning permission to build it and that is going to add something to the Orangery Cost.
In terms of size, once you are over the 30 square meter limit, you can have any size orangery that your space will accommodate.
It’s no good knowing what the average size conservatory is if you don’t have room to build one that size.
Having said that an average size would probably be over 3000mm x 4000mm
Average orangery size is going to be larger than that of the average conservatory because in general, they are more substantial constructions, more like a traditional home extension than a conservatory.
And with that substantial nature comes a substantial price range. Most mid size orangeries will start from around £20,000 and then get up to even £100,000 for a “mega-orangery”
Get your cheque book ready!