High Efficiency Boilers and Water Heaters
These boiler all produce 88% to 95% efficiency. Some can be utilized as water heaters or pool heaters as well. Higher efficiency boilers such as the KN are condensing boilers requiring Cat. II or IV venting. Non-condensing high efficiency (such as the RBI Futera III) will condense in the vent, so Cat. II or IV is still recommended, however these boilers must maintain a higher return temperature to care for the heat exchanger.