I don't understand why it matters how long it takes - it's not as though you have to do anything whilst it's running.
I suppose if your house is configured so you have to sit in the same room it might be noisy, but I put mine on after dinner (at which point we move to the sitting room) and empty it in the morning while the kettle's boiling, so whether it takes ten minutes or three hours just doesn't matter.
What would be the worst figure of speech if you took them literally?
French school children on strike

