I bought this for the heated humidifier of CPAP device. It takes about 30 minutes to heat the water to 100 degrees Celius and then 3 hours to distill a gallon of water. Since I can buy distilled water for about 90-95 cents per gallon, there is only about 60 cents saving (considering the price of electricity here in West. PA is about 12 cents per kw and it takes about 2.6 kw to make a gallon of distiller water.) The advantage for me is that I don't have to haul a gallon of water to my car and then to the second floor of my house and that I don't throw away a gallon plastic jug. I have used it 4 times with no issues. I would suggest that this be plugged into a GFI socket since water and electricity do not mix well.