It's a neat hack but I have to wonder whether the hole through which you pass through the pipes leaks more heat energy to the outside than the fans take to run on an all-indoor system.

Plus, in the winter, you get "free" heating by running the machine completely indoors. Not actually free of course, but free as a side-effect of using the machine for other tasks. Had a friend who tried splitting his electrical service off into a cheaper heat-rate branch to run his bitcoin mining rigs and claimed they were the same as a space heater. I don't think the power company bought it.