Consider Whole-Home Gas Tankless if you: Want to replace your existing gas water heater before it fails. Are building a new home or conducting a major remodeling project. Often run out of hot water. Have limited space and need a water heater that doesn’t take up much room. Want a water heater with a longer lifetime Are willing to pay more upfront to reduce water heating bills by about 30%. Have a large enough natural gas line in your home (typically at least 3/4″) plus space to install the necessary venting. Are willing to take on additional maintenance tasks or schedule a regular maintenance check every few years.