I've been considering LP instant hot water, but still haven't figured out how I'm going to vent the thing. After doing a little research, I've come to the conclusion that you need at least a 3 inch exhaust with either a slight downward run or an upward run with some type of elbow or means for draining off the water generated from burning propane. If electric is the way to go, I'm not convinced because to the tremendous draw. I'd have to fire up the jenny just to take a shower or do dishes