The self-storage industry has three times the footprint than McDonald’s.
Or:
The self-storage industry has three times the footprint of McDonald’s.
The self-storage industry has three times the footprint than McDonald’s.
Or:
The self-storage industry has three times the footprint of McDonald’s.
The first needs a fix:
The self-storage industry has three times more footprint than McDonald’s.
The other is correct and - as Professor Lawler says - simpler.
Z is OK, and quite common. Using three times more just raises the question of whether you're talking about 3X or 4X, plus it requires comparative syntax, which is very fussy.
– John Lawler
Apr 24 '15 at 18:18