Tankless water heaters are not a new concept. In fact they’ve actually been around for over 100 years, and the concept was actually invented by an Englishman (Maughan) in the late 1870s, calling it an (Instant Water Heater).

Edwin Ruud took it step further and innovated water heating for homes in about 1889. He went on to form the Ruud Manufacturing Corporation.

Unlike a traditional (tank) style water heater, the tankless water heater, also known as instantaneous or on-demand water heaters, provide an endless amount of hot water without a storage tank.

We all have a basic understanding of how they must work, and without getting into the nuts and bolts, or the scientic stuff, here it is in common terms.

·         Incoming (cold) water travels through a pipe into the unit, and either a gas burner or an electric element heats the water.

·         Outgoing (output) hot water is delivered to the outlet (faucet).

·         When no hot water is needed the tankless water heater is in the (off) position. Unlike conventional    water heaters, tankless water heaters are very efficient because they do not have standby losses incurred by continuous use of energy to maintain water in a tank to a set temperature.

Tankless water heaters also free up space because of their relatively small size, which can be particularly useful for small homes, apartments, cabins or in crowded kitchens, allowing them to use the area for more productive and profitable use.

In addition, tankless water heaters tend to have longer service lives than tank-based water heaters. A standard tank water heater will have an average life of 10 years, whereas the tankless water heater can last 20 years or longer.  Condition of the incoming water, i.e., (hard, high in minerals) or water with sediment can reduce the life of a tankless water heater, just like it would a standard tank type. Therefore using protections such as water conditioners, or sediment filters can extend the life of your heater greatly.

One drawback of tankless water heaters is that although they theoretically provide endless hot water, most units, particularly electric units, provide heat more slowly than conventional tank water heaters.  Gas tankless water heaters seem to have a bit better performance than electric.  That being said, the size of the unit (gas or electric) plays a large role in the output performance.

Because tankless water heaters don't have the losses associated with tanks, their energy factors are normally higher. Energy factors for gas tankless water heaters typically range from around 0.78 to 0.88, compared with 0.58 to 0.67 for a conventional gas tank and as high as 0.89 for an ultra-efficient gas tank heater

The term "energy factor" characterizes the efficiency of both tank and tankless water heaters. The energy factor is the portion of the energy going into the water heater that gets turned into usable hot water under average conditions. It takes into consideration heat loss through the walls of the tank, up the exhaust flue, and in combustion. The higher the energy factor, the more efficient the heater.

Now one of the most common questions heard is; “How do I know what tankless water heater is best for me?” That’s not an easy question to answer and some of the factors to consider are:

1.      What is my incoming water temperature and pressure (PSI)?

Incoming water temperature plays a significant role in the performance of any tankess water heater. The colder the incoming water, the lower the (rise) in output temperature will be.

PSI (Pounds per square inch) is the measurement of water pressure. All tankless water heaters require some PSI, but that number varies heater by heater. Know your PSI before you buy!

2.      What is the greatest demand needed at any given time?

What is your estimate of (hot) water being used at any given moment?  Example:

My low flow shower head puts out approximately 1.6 gallons per minute (GPM) and my kitchen faucet will need 1.0 GPM, there for assuming I may need to use both faucets (the shower and sink) at one time, my demand or need will be 2.6 GPM.

Therefore, the minimum output my new tankless water heater will need to deliver is 3.0 GPM.

3.      What about venting my tankless water heater?

Venting is only an issue if you’re installing a gas tankless water heater. Electric tankless water heaters do not require venting.

Venting a gas tankless water heater should be completed by a professional plumber/electrician and comply with your local codes.


There are many different brands, styles and sizes of tankless water heaters. It is always best to consult an expert in the field of tankless water heaters before you move on to the next step.

That being said, when you do make the change from traditional water heating to tankless, you’ll never go back. You see, there’s just no good reason in today’s economy to waste money storing hot water.

You don’t let your car run in the garage in case you need to go to the store later in the day, right? Why would you let your hot water tank run day and night, waiting for you to need hot water?

Start saving today!

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