Thank you, sokoloff, Jon Bon, and Enough! It's a plastic hose, and DH is thinking to rearrange some of the furniture so it vents as directly as possible outside. The weather stopped being hot so we haven't had to use it yet (we have since installed a window unit in the main room, so the whole apartment should be comfortable when summer rolls around). Hopefully this solution holds up, if not, I'm sure we'll tinker some more!