I have used the Archimesh addon to create a window. When I try to use the auto hole I get the walls must have thickness error message. I ran the solidify modifier to create the thickness and still get the error. Any suggestions where my problem may be?
Also, is there a better way to create multiple window without creating one and duplicating it numerous times? I can do it with the array modifier but it will not cut the holes.
i think a better way to create window using boolean generate in modifier properties. and about the hole have you try select faces to deleted it.
I hope it answers your question. 
Also worth having a look at box cutter add-on. Since I started using it it has been incredibly useful at times.
For example using box cutter here I would draw out the shape or grid, and then press v and scroll the mouse - which duplicates the boolean shape as many times as needed.
E.g. - this took a few seconds to create.
