I would like to model the whole floor but it's not really required for what we're using it for.
Our company installs Building Management Systems, which control the heating & cooling and manages the energy usage of a building. We use various manufacturers and software packages to do this.

I'm working on a project at the moment LSE 'London School of Economics'. I've put a link to one of the floors there so you can see what I mean.

https://www.dropbox.com/s/7me7c6ox2xf7f ... r.png?dl=0

Cheers.