The nerd in me needed to know this would be cost effective before I decided if it were worth my purchase. I was paying $1 - $1.50 per gallon of water from the store. Where I live, electricity costs about 3.5-4 cents per KWH. It costs me about 10 cents in electricity cost to produce one gallon of distilled water. For the amount of distilled water I need to produce, it will take me about 8 months in savings difference for this thing to actually start saving me money. For me it's worth it. I suggest you look over your utility bill to learn your own KWH charge. Multiply that charge by about 3 to determine your cost to produce a gallon. If you're from California, where costs may be 34 cents per KWH (sorry California friends), this purchase may not make sense for you -unless you have other reasons for producing your own distilled water. Or, perhaps you have solar panels and electric costs are very low for you. Anyway, I hope this is helpful.