Tankless Water Heaters – What’s The Big Deal?
As energy supplies tighten and fuel costs increase, tankless water heaters are gaining attention in some areas because they do not require the storage of hot water. Tankless water heaters are certainly appropriate in some situations, particularly in point of use applications, but all factors should be carefully weighed before replacing a storage (tank-type) water heater with a tankless (instantaneous) water heater as the central hot water supply for a residential application.
A few of the positive attributes that tankless water heater manufacturers promote are: significant energy savings, small & compact, easy to install and an unlimited hot water supply.
It is true that tankless heaters are generally small, compact, wall-hung units. How easy they are to install is dependent on the situation. Installation during new construction would be straight forward. On the other hand, installation in a-retrofit situation could be quite expensive.
The installation of an electric tankless water heater usually requires two 50 amp, 220V circuits. An electrician would be needed to see if additional power is available for the tankless heater.
Gas tankless water heaters are complex appliances with modulating gas and air flows, and sometime with modulating water flows. These complications lead to initial homeowner purchase costs in the range of $500 to $1200. In addition, these units typically require annual servicing by a trained technician. These quotes are for the product only; installation would be an additional cost.
The manufacturers of tankless water heaters stress that their units provide an unlimited supply of hot water. That is true, as long as you do not exceed your tankless model's ability to heat water. In a storage water heater, the amount of hot water immediately available for use is not dependent on the flow rate or the inlet temperature.
Because tankless units heat the water as it is used, the energy requirements placed on the heater depend on both the amount of water being used (flow rate) and the temperature increase required for that water. Obviously, large flow demands, very cold ground water and elevated hot water temperatures place larger demands on the tankless water heater.
Tankless water heaters do have some advantages. They are compact and are easy to drain; consequently, they could be ideal for applications where space is a premium or in small vacation homes. In addition, they could serve quite effectively in point of use applications. However, their use as the central source of hot water in a residence should be carefully considered. If a customer regularly runs out of hot water from his storage water heater, the most cost-effective solution is the purchase of a larger, correctly sized, high-efficiency storage water heater.