stevendaryl said: The only problem is that now the vacuum chamber is full of water vapor. If you open the door to the chamber to get your clothes out, the vapor would condense again, getting your clothes wet all over.

This isn't the only problem. As @sophiecentaur pointed out, this isn't even a problem. Your main problem will be constructing a vacuum chamber that 1) is large enough to accommodate a standard dryer load, 2) strong enough to stand up to the forces on the walls of the chamber, and 3) light enough that you don't need a crane and floor reinforcements to install it in an upstairs laundry room. The three of these conditions together might be tricky.Aside from that, it's not a bad idea. You won't need to pull a very high vacuum, but it probably won't be as fast as you envision (as anyone who has tried to boil off solvent under vacuum can tell you). There's still quite a bit of water even in clothes that have been wrung out, but it's spread out over a large surface area, so that helps. The water will cool as it evaporates, meaning the evaporation rate will slow as the clothes get drier. The other issue is that water hydrates many types of fiber (cotton in particular), and dehydrating them completely might give you really bad wrinkles (this is why most clothes irons have a built-in steamer function).The most expeditious way to do this might be to combine a tumbler and optional heating with a low vacuum (say 0.5 atm). But then the question becomes: how much better is this than what we have now, and would people be willing to pay for the difference. Dryers are pretty cheap, and adding a pump might increase their cost by $100 USD or more, especially if you want to use an oil-free pump (probably a necessity since I doubt anyone wants to take their dryer to Jiffy Lube for an oil change).