I use 1.5gal of distilled water per night between 3 humidifiers. I purchased this distiller in an effort to bring the distillation process home for various reasons. The distillation process took about 3 hours, and dropped my tap water PPM from 673 to 19. My tap water is run through a whole house filter and softener. I was expecting 0PPM after the distiller. I will try my fridge water next, and then my RO to see if the PPM drops further. 4 stars because I was expecting ~0PPM. Otherwise the machine itself worked well on the first try. I need it to generate 46 more gallons to break even on my purchase compared to buying distilled water from the store. I hope it lasts at least that long.