I think that's a good idea. And if you stuck the pipe outside of your window facing towards the ground, you would lower the risk of water entering your computer seeing as rain falls, but then again, there's always water vapor. I think a filter at the end of the hose should do it though. I want to try that. Would adding more hoses to more fans make your PC even cooler? I'm thinking it will but I'm not sure.
-Dan The Man