Water Heaters – Tankless Vs. Tank


With all the talk about going “Green” these days, the debate over tankless vs. tank type water heaters is becoming more a factor in making a decision when replacing that old rusty klunker in the garage.

Let’s discuss some of the issues involved in making that decision. A tankless water heater, sometimes erroneously referred to as an “instantaneous”, costs about double the cost of a tank type. It does, however, take up much less space as they are typically mounted on the wall and are about the size of a medium suitcase.

When replacing a tank with a tank, you can usually connect to the existing vent, gas piping, water piping, and relief line without too much problem. Replacing a tank water heater with a tankless water heater will involve new venting with stainless steel pipe, and rerouting the gas and water piping to the tankless water heater unit. Since the tankless fires at around 200,000 btu, the gas line usually has to be upsized. Depending on the model, the tankless may require electrical wiring as well.

Although the tank fires at a much lower rate using much less fuel, it does so throughout the day even when hot water is not being used so that it can maintain the set temperature. The tankless only fires when hot water is needed. The water stored in the tank also loses heat through the outer jacket. The tankless doesn’t store water so it can never run out of hot water.

Your plumbing contractor can give you much more information on this debate. There are also many internet sites that delve into the different issues to help you make an intelligent decision. What may be right for one application may not meet the needs of another.