How Condensing Tankless Water Heaters Work

A condensing water heater utilizes the burnt exhaust gases to preheat the cold incoming water. This process also cools the exhaust gas temperature. Exhaust temperatures in conventional heaters usually run 310F to 360F. Condensing water heater exhausts usually run between 95F to 130F. This temperature reduction allows the use of PVC rather than the more expensive Category III vent pipe.