Checking out some new tankless water heaters. Is a gas tankless water heater worth it? Many people say yes. Here are a few things to consider. -Most tankless water heater basic models are 80-82% energy efficient. This means is you bought 10 gallons of gasoline to put in your car it would use 8 gallons and the other 2 would be wasted energy out the exhaust. These models provide no real monthly energy savings over a standard gas tank water heater. If you looking for energy savings go with a more efficient model that operates at 90% plus energy efficiency and you will most likely have monthly energy savings over your basic gas tank water heater. -There is nothing "instant" about the hot water delivery from a tankless water heater! You will have to wait a little longer for a basic tankless water heater setup over your existing basic gas tank water heater. On a tankless the gas burner only lights when you turn on the hot water. There is no hot water sitting in a tank read