Stay clear of Takagi T-K4U-OS-NG Natural Gas Whole House 190000 BTU Outdoor Whole House Tankless Water Heater ratings

Takagi, T-K4U-OS, Whole House, Natural Gas, Tankless Water Heaters, Gas/Propane Featuring a power vented flue this tankless water heater uses sealed combustion and is fully modulated, making it perfect for domestic hot water systems. It can also be used with water storage tanks, recirculation systems, hydronic heating systems, radiant floor heating systems, and/or combined domestic & heating applications while complying with Ultra-Low NOx regulations, lead free standards, and being Energy Star Qualified.Features:Energy Star QualifiedOverheat Cutoff Fuse and Built-in Freeze ProtectionEfficient, Durable and Easy to InstallStronger than Standard Copper and More Resilient Against ErosionComplies with Lead Free StandardsIncludes Built-in Temperature Controller and Diagnostics3 or 4 Inch VentingUp to 8 Gallons Per MinuteAcceptable for up to 4 ShowersElectric Ignition HRS35 copper is an alloy that is 99.5% pure copper with a .5% mixture of other elements, this alloy is much stronger and harder than the standard C1220, which is the copper. HRS35 has 8 times the tensile strength of standard copper Energy Star is an international standard for energy efficient consumer products originated in the United States of America. It was created in 1992 by the Environmental Protection Agency and the Department of Energy. Devices carrying the Energy Star service mark, such as computer products and peripherals, kitchen appliances, buildings and other products, generally use 20%A30% less energy than required by federal standards.Following the South Coast Air Quality Management District (AQMD) , several other AQMDs have adopted regulations to require residential water heater (<75, 000 Btu/hr heat input) NOx emission to be less than 10 nanograms per joule of heat output. The South Coast AQMD also requires that tankless water heaters to have NOx emission less than less than 14 nanograms per joule of heat output or less than