It is not only a matter of texture resolutions, but also of draw calls. If you have the entire housee as on emesh, you will always have a draw call for the whole house, no matter where you are looking at. Also you would need a really high lightmap resolution to capure enough details.
In your example, I would even split the pink part into smaller sections.
Give the walls some thickness and make them modular. Walls, window awnings, etc.
For the window sections, you could even choose a 1024 texture…
The only advantage of having it in one mesh is that the shading for all parts would be dertived from the same irradiance cache and thus be shaded continously…