Confused about window airs?

Ok so here is the deal. I am thinking that instead of buying a industrial van to just buy 2 window airs or one. Ok so I can get two 5,000 btu window airs for 100$ a pieace. Ok so that would mean 200 for the both. And a 10,000BTU is 245$. Ok so now that we got that. Will the two 5,000 btus cool as if I had a 10,000Btu already? I am so lost when it comes to stuff like this. I dont want to waste more money on a 10,000 btu when I could buy two 5,000btu's...