August 2007
The Truth About Tankless

Storage space is something just about everyone wishes they had more of in their home, but when it comes to water heaters, that may not be the case.

Ready to toss your old water heater? Be sure to do your research before picking a new one.

Tankless water heaters, also called demand or instantaneous water heaters, offer an alternative to the traditional natural gas storage water heaters. But they aren't for everyone.

Tankless water heaters only come on when there is a demand for hot water, making them more energy efficient in some cases. When you turn on hot water, cold water travels through the tankless unit where a gas burner heats the water. When you turn the hot water off, the unit shuts off. With storage models, standby heat loss occurs because water stored in the tank is heated periodically in order to maintain the temperature, even if no hot water is used.

The flow rate from a tankless water heater is limited, which means some cannot supply enough hot water for multiple uses at once. If someone is taking a shower at the same time a load of clothes is being washed in hot water, the hot water may be insufficient; it can also take a long time to fill up a bathtub. You can install a whole-house type tankless water heater or install more than one tankless unit; single tankless water heaters (or point-of-use) can be installed for specific appliances that use a lot of hot water, such as dishwashers or washing machines.

A tankless water heater may be a good option for a one- or two-person household or a vacation home, but can be inadequate for a larger household and everyday use. Also keep in mind that energy savings may be offset by the fact that there is hot water on demand--this can cause people to use more of it.

Although tankless heaters are sometimes more energy efficient, those models with a constantly burning pilot light can offset any savings. If you use one that has a standing pilot light, turn it off when it's not in use for more energy savings. You can also choose one that has an intermittent ignition device, which lights the pilot light only when needed.

Energy efficiency can also be offset by mineral buildup in the unit caused by hard water. Proper maintenance is key to preserving the efficiency of a tankless water heater.

Tankless water heaters are available for indoor and outdoor applications and can be purchased at home improvement stores, but should be installed by a licensed contractor.

They can be used in new construction or in existing homes. However, when retrofitting an existing gas water heater, have a licensed contractor look at your gas line to determine whether or not it meets the requirements for a tankless water heater—the gas requirements are generally much larger than for a storage water heater, so it is possible that upgrades will be necessary in order to install the unit.

Tankless water heaters require direct venting, so have the space checked to see that venting is possible. Retrofitting for a tankless water heater can be costly if several upgrades must be made.

Generally, tankless water heaters cost about two times as much as conventional storage water heaters. However, some sources say they last about twice as long. Because tankless water heaters do not store water, they are less inclined to corrode.

Both tankless and storage water heaters have their advantages in certain applications, but it is important to determine what best fits your needs. Have a qualified contractor evaluate the type and size of unit that you'll need based on your peak demand.

So, when it comes down to it, the truth about a tankless water heater is that you must do your research before deciding if it's right for you.

Read other articles from The Walton EMC Gasette:
10 Ways to Maximize Your Hot Water Efficiency
Read other articles from The Walton EMC Gasette:
Safety First: Have the Water Heater Know-How
Read other articles from The Walton EMC Gasette:
Gas Up the Stove
This month's recipe features Summertime Ice Cream Dessert