TECHNICAL QUESTIONS T-1: How is venting accomplished I see no stack in the pictures thanks -Bob Jan-11-09 A: From 4"- 5" vent pipe you can go straight up or 90 degree out the wall with a rain cap on it. This unit is in the garage and is on for such a short time, it hasn't been vented yet. We have never noticed any fumes. It is always best to go ahead and vent anyway. T-2: Does the on demand tankless hot water heater allow for setting of temperature? If so, what is the range available? A: It have 3 ways to set the temperature: by water flow, a summer and winter setting and a low > high knob. T-3: Where does one get the vent and wall flue? How much do those typically run? A: You can get a 4"- 5" twin wall galvanized pipes and a rain cap from a home improvement or hardware store for around $25. T-4 What is the thickness of the heat exchanger? A: T-6 What are the heating coils made of? A: www.cozyhotwater.com