A. O. Smith announces the addition of X3 scale prevention technology to its full line of residential condensing gas tankless water heaters. Designed with both consumers and contractors in mind, X3 Technology prevents scale buildup in a tankless unit, eliminating the need for routine descaling maintenance, tripling the expected lifetime of a unit and enabling it to run at like-new performance and efficiency. X3 Technology means the end user never has to descale a tankless water heater again – alleviating maintenance time for contractors and reducing ownership costs for homeowners. The units use up to 199,000 Btu/h of natural gas to deliver a continuous supply of hot water to residential applications, A. O. Smith points out.