Pros and Cons of a Tankless Water Heater

A tankless water system.

There are many pros and cons to a tankless water system. Here are some to consider.

Pro: Savings

The initial costs of a tankless system may be substantial. However, long term savings result from the on-demand design. Tank systems maintain a required temperature calling upon energy consumption more than a tankless system.

Pro: Unlimited Hot Water

Since hot water is produced on demand while passing through the heating coils, there is always an unlimited supply.

Pro: Less Space

Without the need for a storage tank, tankless water heaters take up less space and can be mounted in tight areas like inside a cabinet or on a wall.

Pro: Less Risk of Water Damage

Most water damage in a home usually comes from ruptured water tanks. Therefore, any water damage using a tankless system would have to be from faulty pipes.

Pro: Temperature Constant

Tankless systems employ temperature compensating valves that eliminate fluctuations caused by tank systems where pressure affects temperature. Most new tankless systems use a bypass and a mixing valve system to stabilize water pressure and temperature.

Con: Cost of Installation

This is a considerable factor especially when having to retrofit a home unit. When storing water heater units are replaced by a tankless system, electrical wiring or a gas pipelines usually have to be replaced with larger ones due to code requirements. Most gas-powered tankless systems require a much higher range for a modulating gas valve from as low as 10,000 to more than 1,000,000 BTUs. Electrical powered tankless systems will require wiring corresponding to 10 or 8 mm compared to traditional 10 or 6. In gas-powered tankless systems greater pressure and volume requirements must also be met.

Con: Heat Sources

These are limited to either gas or electricity denying the use of any renewable heat sources such as solar.

Con: Wait on Hot Water

The use of a tankless water system, although providing constant hot water, will have a delay, especially carrying to a far off faucets in the building. Since there is no standing hot water in a tank, the water heated on demand takes a few moments and then must travel.

Con: Intermittent Water is Cold

Due to the fact there is a short delay between when water begins flowing and when the system’s heat detector activates, sort periods of hot then cold water will occur. Once the water does start flowing in a continuous operation like a shower or washing machine, turning a hot water faucet on and off at one location may result in spurts of cold during each separate action. However, once water flow brings hot water it will continue indefinitely.

Con: Maintaining Shower Temperature

This can be a tricky task that will need a little practice. Since a shower operation calls for a longer timed flow of water, that flow will have a proportional effect upon the temperature – the faster the water flows through the heating coil, the less time it is heated. Therefore, a slower flow presents hotter water. This presents a need to adjust the water flow to find that “perfect” shower temperature that mixes hot and cold from a single faucet source.