Answer: -If you want to add a power venter you already have to a water heater you want to buy, then you need to get a professional. Power venting is not a do-it-yourself project. You obviously have limited knowledge, and the wiring alone can be difficult. If you don't vent properly, the money you save will do you no good if you don't wake up one morning. -Some power venters are capable of venting two separate appliances, but the wiring and controls are not something for a DIY. I don't understand why you want to use a power venter. Do you have some special venting requirements? Before you answer, do some research on the venting requirements of a direct vent water heater vs. a power vent water heater. You should pay special attention to the height requirements. Some of them are too tall to replace a conventional water heater.