First of all, we would like to say that the heat loss is very equal with good insulation, and the door is used only when baking bread, that is, after removing the embers. Otherwise, the oven is always up and the door is hardly needed. Model "FVR" is available only with pre-set door and model "TOP" is available only with fixed ceramic door. It is not possible to change them, because they are two different models and it does not fit dimensionally. The model "Indirect" is also available only in one version.