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Tankless Water Heaters

Topic: A Word from an Expert

Tankless water heaters can provide endless hot water and avoid standby heat loss associated with traditional water heaters.

 

Tankless water heaters (a.k.a. "on demand" water heaters), are a very efficient way of supplying domestic hot water. A tankless water heater requires a gas line and an electrical source. As the name indicates, this type of water heater does not have a tank. For this simple fact, they are smaller and lighter than a conventional water heater, which allows them to be wall mounted. A tankless water heater operates only when a there is a need for hot water, which means it operates for shorter amounts of time and with lower gas usage then a conventional water heater.

 

Tankless water heaters are great and there is no question about it. However, they are limited in the amount of hot water that they can deliver at once. Lets take a closer look at the Rinnai R94LSi as an example.  It delivers 9.4 GPM (gallons per minute) at 35 degrees Fahrenheit of temperature rise and 4.4 GPM at 75 degrees Fahrenheit of temperature rise.

 

This brings us to two of the most important things that every homeowner should know before buying a tankless water heater:

  1. A hot shower requires the water to be about 110-120 degrees Fahrenheit. Lets keep this in mind. During winter in Chicago for example, an incoming water temperature from the city is around 40 degrees Fahrenheit. To bring this water temperature from 40 degrees to 115 degrees for a hot shower, a 75 degree rise is needed. Having said that, the Rinnai R94LSi will only deliver a max of 4.4 GPM during winter in Chicago. It all depends on what part of the country do you live in. If you live in Miami, for example, then the incoming city water temperature is much higher than in Chicago or in other northern parts of the country all year round. A simple rule is this: the warmer the incoming city water temperature is, the more GPM will you get out of the unit.
  2. What is 4.4 GPM? A regular shower head uses about 2.1 GPM. This means that at 4.4 GPM, two showers can be run at the same time with an endless supply of hot water. Problems begin when the two showers are used and someone turns on the laundry or dishwasher. When this happens, there will not be enough hot water to satisfy everyone's needs.

 

If a house has three or more bathrooms, a hot tub, a couple of the rain-type shower heads, and several appliances requiring water, the GPM to satisfy all of those needs at the same time is pretty high. To show a good contrast, let's say that eight people live in the house. If that's the case then there is a very good chance that one tankless water heater will not be enough. When this is the situation two, or even three, tankless water heaters need to be put together to work simultaneously to deliver the necessary GPM to suit everyone's needs.

 

The way of figuring out which tankless water heater to get and how many you need is based on your the number of bathrooms, types of appliances, number of people in the house, and their lifestyle. To make sure you get an accurate sizing estimate, speak with an expert by calling us at 866-554-HEAT (4328) today.

 

At eComfort.com we carry only the best in tankless technology, including Rinnai. Rinnai is the only brand of tankless water heaters that are made in Japan. Their superior quality and performance sets them apart from the competition. All of the Rinnai tankless water heaters can be vented through the wall or through the roof. Rinnai makes their own venting material, consisting of stainless steel pipe on the inside and a special high-temperature-resistant plastic coating on the outside. If a horizontal vent is more appropriate, then a standard horizontal kit is available. It consists of a 90 degree elbow and a 12 inch pipe with an outside wall termination. If 12 inches of pipe is not enough to penetrate to the outside, additional pipe extensions are available. However, if the unit needs to be vented through the roof, the distance from the unit's vent discharge to the roof need to be known. Once the vent height is known, appropriate vent pipe and accessories can be purchased. In addition to the vent pipe, a plumbing installation kit is a highly recommended item. It reduces installation time and provides immediate water shut off to the unit in case of an emergency.

 

Call eComfort.com at 1-886-554-HEAT (4328) or send an email to sales@eComfort.com if you have any other questions. We are here to help!

 

This article was published on February 10, 2009.

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