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Tankless Water Heater Buying Guide


Content: (click the links below to be taken to each section on this page)
What is a Tankless Water Heater?
How do Tankless Water Heaters work?
Selecting a Tankless Water Heater
Tank Water Heater Vs Tankless Water Heater
Tankless Water Heater Installation and Maintenance
Tankless Water Heater Manufacturers
Tankless Water Heater Benefits and Advantages
Tankless Water Heater Videos
Tankless Water Heater Savings Calculator
Find Tankless Water Heater Installers
Tankless Water Heater Comments

What is a Tankless Water Heater?

water heaters Tankless Water Heaters, also called Instantaneous or Demand Water Heaters, provide hot water only as it is needed. Traditional storage water heaters produce standby energy losses that cost you money. We do not leave our homes heated while vacationing. We only heat our homes when there is a demand for heat. In the same way, a Tankless Water Heater is used only when there is a demand for hot water.

How do Tankless Water Heaters work?

Electric Demand Water Heater Tankless Water Heaters heat water directly without the use of a storage tank. Therefore, they avoid the standby heat losses associated with storage water heaters. When a hot water tap is turned on, cold water travels through a pipe into the unit. In an electric Tankless Water Heater an electric element heats the water. In a gas-fired Tankless Water Heater a gas burner heats the water. As a result, Tankless Water Heaters deliver a constant supply of hot water. You don't need to wait for a storage tank to fill up with enough hot water. Typically, Tankless Water Heaters provide hot water at a rate of 2 – 5 gallons (7.6 – 15.2 liters) per minute. Typically, gas-fired Tankless Water Heaters will produce higher flow rates than electric Tankless Water Heaters. Some smaller Tankless Water Heaters, however, cannot supply enough hot water for simultaneous, multiple uses in large households. For example, taking a shower and running the dishwasher at the same time can stretch a Tankless Water Heater to its limit. To overcome this problem, you can install a “whole house” type Tankless Water Heater or install two or more Tankless Water Heaters, connected in parallel for simultaneous demands of hot water. You can also install separate Tankless Water Heaters for appliances—such as a clothes washer or dishwater—that use a lot of hot water in your home.

Other applications for Tankless Water Heaters include the following:
Tankless Water Heater Dishwasher Application Tankless Water Heater Bathroom and Kitchen Application

For homes that use 41 gallons or less of hot water daily, Tankless Water Heaters can be 24% – 34% more energy efficient than conventional storage tank water heaters. They can be 8% – 14% more energy efficient for homes that use a lot of hot water, around 86 gallons per day. You can achieve an even greater energy savings of 27% – 50% if you install a Tankless Water Heater at each hot water outlet.

Selecting a Tankless Water Heater

Before buying a Tankless Water Heater, consider the following:
  1. Fuel Type
  2. Location, Size and Demand
  3. Application
1. Fuel Type

The first thing that you'll need to decide when selecting a Tankless Water Heater is the fuel type. You will need to select between an Electric Tankless Water Heater (like Eemax Tankless Water Heaters or Stiebel Eltron Tankless Water Heaters) or a Gas-Fired Tankless Water Heater (like Rheem Tankless Water Heaters).


If you plan to purchase an Electric Tankless Water Heater, consider the Electrical Requirements:

Voltage

Many retailers sell units that will accommodate 110V, 120V, 208V, 220V, 240V, and 277V.


Amperage

Different Electric Tankless Water Heaters will have various requirements in amp draw. You will want to ensure that you can support the electrical demands of your Electric Tankless Water Heater.


Circuit Breaker

You must ensure that you have a circuit or circuits that will support your Electric Tankless Water Heater. It may be necessary to put your Electric Tankless Water Heater on its own circuit or circuits.


You should consult with a qualified, licensed electrician for more information.



If you plan to purchase a Gas-Fired Tankless Water Heater, consider the Gas-Type and Venting Requirements:

Gas Venting

You will first need to identify whether your gas type is Natural Gas or Propane. It is imperitive that you examine your current gas line to ensure that it will meet the requirments of your new Gas-Fired Tankless Water Heater. The requirements of the Tankless Water Heater may exceed that of your existing tank-style water heater.

Next, you will need to consider venting requirements for your specific installation scenario. There are a few important things to keep in mind when purchasing the gas venting accessories for your Gas-Fired Tankless Water Heater.

Be sure that you purchase Category III stainless steel (UL1738 certified) venting for your Gas-Fired Tankless Water Heater. "Type B" venting accessories are not acceptable. Also, be sure to check local building code to ensure that your specific needs will be completely met.

Additionally, many Tankless Water Heater manufacturers offer gas venting "kits". It is recommended that customers evaluate the needs of their specific installation to ensure that they will be getting all of the necessary gas venting accessories. Depending on where you will be installing the Tankless Water Heater, a pre-made kit will probably not meet your needs. Ensure that you measure out the vent route and consider where the discharge will go through the wall or ceiling, consider the necessary clearances, and consider ample access to air for combustion, then buy the appropriate gas venting pieces. *Note: Gas-Fired Tankless Water Heaters may still require a minimal electrical connection. Be sure to review installation requirements for the units you are considering for purchase.



2. Location, Size, and Demand

When deciding which Tankless Water Heater to purchase, you will also need to consider where you will need hot water. Are you looking for a unit that will heat the water at one bathroom sink (single point application), an entire bathroom (multipoint application), or an entire house, apartment, or condo (whole house application)? It is important to recognize the number of fixtures that will require hot water. Each fixture will have its own demands. The chart below illustrates the typical flow rates (demand) for some standard fixtures:

Typical Flow Rates in Gallons per Minute (gpm)
Fixture TypeLavatoryBathtubShowerKitchen SinkPastry SinkLaundry SinkDish-washer
Flow Rates0.52.0 – 4.01.5 – 3.01.0 – 1.51.5 – 2.52.5 – 3.01.0 – 3.0

The flow rate is especially important, since Tankless Water Heaters will generate a temperature rise based on the flow rate demanded.

For example, a Stiebel Eltron Tempra 12, running on 240 Volt power, will raise the water temperature by 54°F at 1.5 gpm, 36°F at 2.25 gpm, and 27°F at 3.0 gpm, above the ambient incoming water temperature, up to 125°F.

A larger unit, like the Stiebel Eltron Tempra 36, running on 240 Volt power, will raise the water temperature by 92°F at 1.5 gpm, 92°F at 2.25 gpm, and 82°F at 3.0 gpm, above the ambient incoming water temperature, up to 125°F.

Temperature Rise Based on Flow Rate, Up to 125°F
Flow Rate1.5 gpm2.25 gpm3.0 gpm
Tempra 1254°F36°F27°F
Tempra 3692°F92°F82°F

This means that if you are using a 1.5 gpm shower and a 1.5 gpm kitchen sink simultaneously, a total demand of 3.0 gpm, the Stiebel Eltron Tempra 12 will raise the temperature 27°F, whereas the Stiebel Eltron Tempra 36 will raise the temperature 82°F.

Cool (Northern) Climate, Warm (Southern) Climate Next, you should look at your ambient incoming water temperature. If you live in a cold climate, like New York, your incoming water temperature will likely be much lower than if you live in a warm climate, like Florida. Your best bet is to find out how much temperature rise you will need in order for your hot water to reach the desired heat. If the ambient incoming water temperature for your shower is 65°F, you are using a 2.0 gpm shower, and you want to raise that temperature to 115°F, you will want to look for a Tankless Water Heater that will provide at least a 50°F temperature rise at 2.0 gpm (115°F - 65°F = 50°F). However, if you anticipate additional simultaneous demand, such as the hot water from a sink being used while someone is showering, you will need to add the sink's gpm to the shower's gpm in order to determine your overall gpm demand and then find the temperature rise necessary to meet your overall needs.

Incoming Water
60° F
Incoming Water
2 gpm Shower
2 gpm
Shower
Desired Output Water Temperature
110° F
Desired Output Water Temperature
Tankless Water Heater that produces a 50°F temperature rise at 2 gpm
You will need a Tankless Water Heater that produces a 50°F temperature rise at 2 gpm


3. Application

You may have a specific application in mind for your Tankless Water Heater. Here are a few examples of the different models and their functionality for a specific application:

Electric Point of Use Tankless Water Heaters
A single point application is one where only one fixture will require an Electric Tankless Water Heater. Here are some examples of Electric Point of Use Tankless Water Heaters:

Eemax Single Point Electric Tankless Water Heaters
Stiebel Eltron Point of Use Electric Tankless Water Heaters
Chronomite Instant-Flow SR Electric Tankless Water Heaters

Eemax Flow Controlled
The "Flow Controlled" range of water heaters from Eemax are ideally suited to serve two points, like two sinks, in close proximity. Here is an example of Flow Controlled Electric Tankless Water Heaters:

Eemax Flow Controlled Electric Tankless Water Heaters

Thermostatic
The Thermostatic Tankless Water Heater serves as a booster for temperature loss from long pipe runs, dishwashers and sanitation. Thermostatic units are good for applications where precise temperature control is essential; such as schools, hospitals and laboratories. Here are some examples of Thermostatic Electric Tankless Water Heaters:

Eemax Thermostatic Electric Tankless Water Heaters
Stiebel Eltron DHC-E 8 Electric Tankless Water Heater
Stiebel Eltron DHC-E 10 Electric Tankless Water Heater

Eemax Series Two
Eemax Series Two units are ideally suited for residential showers, entire bathrooms, smaller houses, condos, summer cabins and apartments. They will also accommodate industrial boosters, higher flow rate applications such as wash down stations and higher flow rate accurate temperature control applications such as photo labs. Here is an example of Eemax Series Two Electric Tankless Water Heaters:

Eemax Series Two Electric Tankless Water Heaters

Whole House Indoor Use
Larger Whole House units are designed to serve an entire house, apartment, condo, or cabin, where multiple points of use will exist. Here are some examples of Whole House Electric Tankless Water Heaters for Indoor use:

Eemax EX280T2T Series Three Electric Tankless Water Heater
Stiebel Eltron Tempra Series Electric Tankless Water Heaters

Whole House Outdoor Use
Larger Whole House units are designed to serve an entire house, apartment, condo, or cabin, where multiple points of use will exist. Here are some examples of Whole House Electric Tankless Water Heaters for Outdoor use:

Rheem Outdoor Gas-Fired Tankless Water Heaters

Tank Water Heater Vs Tankless Water Heater


Tank Water Heater Vs Tankless Water Heater


Tankless Water Heater Installation and Maintenance

Proper installation and maintenance of your Tankless Water Heater can optimize its energy efficiency.

Proper installation depends on many factors. These factors include climate and local building code requirements. You should have a qualified, licensed plumbing and heating contractor install your Tankless Water Heater.

Do the following when selecting a contractor: Be sure you contractor first consults the manufacturer’s installation and instruction materials. Manufacturers usually provide the necessary installation and instruction manuals with the product. Your contractor should also contact your municipality for information about obtaining a permit, if necessary, and about local water heater installation codes.

Many Tankless Water Heaters have a life expectancy of more than 20 years. They also have easily replaceable parts that extend their life by many more years. In contrast, storage water heaters last 10 – 15 years.

You should consult the manufacturer's website or literature, such as the manual, for detailed warranty information.

Periodic water heater maintenance can significantly extend your water heater's life and minimize loss of efficiency. Read your owner's manual for specific maintenance recommendations.

water heaters


Tankless Water Heater Manufacturers

There are many manufacturers of Tankless Water Heaters, including those below:

Eemax Tankless Water HeatersEemax Tankless Water Heaters

Stiebel Eltron Tankless Water HeatersStiebel Eltron Tankless Water Heaters

Chronomite Tankless Water HeatersChronomite Tankless Water Heaters

Rheem Tankless Water HeatersRheem Tankless Water Heaters

Bosch Tankless Water HeatersBosch Tankless Water Heaters

You may also want to review Gas Venting accessories for your Gas-Fired Tankless Water Heater:

ProTech Systems

Dura Vent

NovaFlex

Dundas Jafine

Broan-Nutone

Tankless Water Heater Benefits and Advantages

There are a lot of great reasons to invest in a tankless water heater over a tank water heater but these are the advantages that we feel are the most important in helping you to make an informed decision.

Endless Supply of Hot Water

By far the best reason to have a tankless water heater is for the endless supply of water that it provides. If you have ever run out of hot water during a shower, then you will understand why this is so important. A tankless water heater provides the fix for you as the water can continue to run for as long as it is required. In heavy water use houses this will mean the entire family can take showers, one after another, without having to wait for the water to refill.

Save Money and Energy

Tankless water heaters are much more efficient than normal tank water heaters when it comes to energy usage as they do not waste energy during stand by times. Installing one in your house can lead to a decrease in your energy bill right away, which in turn usually leads to less money you have to shell out each month on your bill. Tankless water heaters can be a more expensive upfront investment, but over the course of its life, the energy savings should pay you back the extra money spent and more.

Save Space

If you are investing in an electric tankless water heater then you can often enjoy a lot of extra space. Electric heaters are usually a fourth of the size of a tank water heater. If the heater is in an indoor closet, that space can go to storing more clothing and household items and if it is in the garage then the possibilities are endless on what you can use the extra space for.

Less Rust

Another benefit of a tankless water heater is that it is less likely to rust. Since the water is not stored in the tank it has a lot less chance to rust and pollute the water supply. Investing in a good tankless water heater, more often than not, will save you the hassle of having to replace the heater due to rust.

Tankless Water Heater Videos





Tankless Water Heater Buying Guide Video



Chronomite: How to Install a Electric Tankless Water Heater



Considerations when Installing a Tankless Water Heater



Eemax Tank Water Heaters vs Tankless Water Heaters



Eemax Tankless Water Heater Savings



Eemax: How to Install a Tankless Water Heater



Everclens Tankless Water Heater Cleaning Kit



Rheem Tankless Water Heaters - How to Select the Right One

Tankless Water Heater Savings Calculator


Estimate Your Savings!


Monthly Utility Bill:
Estimated Savings*
Electric Tankless Gas Tankless
Monthly
Yearly
Click Here for Federal Tax Credit Information
* These numbers are based on normal household water use and can vary dependent on the type of water heater and the amount of use.


Find Tankless Water Heater Installers


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Tankless Water Heater Comments



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