Electric vs Gas Tankless Water Heaters

Gas Versus Electric: Tankless Water Heaters 

Tankless water heaters are all the rage nowadays. Everybody is wanting one whether or not they truly know why. They are also known as instantaneous water heaters, due to the fact that they heat the water instantly. People want tankless water heaters for 2 main reasons; they provide hot water instantaneously and you don’t run out of hot water before you are finished with your shower. But, before jumping in feet first, be sure to do your research.

How Do They Work?

First off, lets figure out how a tankless water heater works. Tankless water heaters heat water directly instead of having water stored in a storage tank. When water is run through it, cold water goes through a pipe and into the unit. The cold water travels over an electric heating element or over a gas burner which in turn heats the water as it exits the water heater.

Therefore, you have a constant supply of hot water for whatever task you may be needing it for. Generally speaking, tankless water heaters stay turned off and are activated when the sensor senses a flow of water going into the unit.

Disadvantages: What Are They?

There are a couple of disadvantages to tankless water heaters that need to be addressed. For one thing, there is a greater delay in receiving hot water. Because the water is not already heated in a tank you have to wait longer for the heating element to get hot enough to heat the water passing across it.

Secondly, there is not a great range of heating source options. You can use electricity, natural gas or propane. Because of the fact that you can use electricity, you can also use solar power. Tank systems can use other heating sources such as geothermal heating, ground coupled heating exchange, central heating and district heating.

Thirdly, there is quite the variation in how hot the water can get. Not only does it depend on how cold the water is to begin with, but it also depends on how fast the water is flowing over the heating unit. The faster the water is flowing, the less time the water has to heat while traveling back out of the pipe.

Another disadvantage is that if a large number of homes in the area have tankless water heaters, then it is likely that the energy usage cost will rise during specific hours of the day. Lastly, if you have an electric tankless water heater and the power goes out then you are also left without hot water, whereas with a gas tankless water heater you could still have hot water regardless of the electricity being out.

What Kinds of Tankless Water Heaters Are Out There?

There are two different kinds of tankless water heaters; Gas and Electric. Gas tankless water heaters can run on one of two things; natural gas or propane. Normally a company will not produce separate units for them both, but instead a single unit can run on either the natural gas or the propane that is needed.

What Do I Need to Know Before Deciding?

There are pros and cons to each one; electric and gas. To properly gauge which one is better suited for you and your situation you need to look at the pros and cons of each one and ask yourself a few questions:

Standard Tank Water Heaters

A standard tank water heater is a tank that holds a large amount of water. They can hold as little as 23 gallons and as much as 80 gallons. Water goes into the tank and is heated by an electric coil or a flame produced by gasses. The water then exits the tank through a pipe to go to whichever part of your house you need it for, whether it be your kitchen sink or your shower.

You only have as much hot water as your tank can hold. So, if you have a 23 gallon tank then you only get 23 gallons of hot water before your water will run cold and you have to let the water heat back up. This is one reason many people have been turning to the tankless water heaters     

How Much Does it Cost?

Let’s delve into a few very important things that you need to consider; a tankless water heater is going to cost a fair amount of money. For an electric one that will heat enough water for an entire house will cost you up to $700. Whereas a gas one able to handle the same load will cost you at least $1000, if not more.

These costs do not include the cost of installation either. The cost of installation of any tankless water heater is quite expensive. Tankless water heaters have very complex systems and venting requirements and in most cases existing gas lines cannot be used. This means that all new gas lines will have to be installed as well. And unless the gas unit is a condensed one then it will need to have a great ventilation system installed as well.

How Efficient Are Tankless Water Heaters?

Efficiency of gas versus electric is quite drastic as well. Gas tankless water heaters usually top out their efficiency at around 85%. Alternatively, the electric tankless water heaters tend to be at least 98% efficient. Although natural gas tends to be cheaper in most areas, due to the efficiency of the electric tankless water heaters, they tend to be more worth it in the long run.


Electric tankless water heaters require almost no maintenance and upkeep. The only thing you have to do as maintenance is clean the filter and flush the unit annually.

Gas tankless water heaters have to be maintained yearly by a certified and trained technician. Not only do the technicians have to make sure that the gas is combusting properly, but the unit also has to be cleaned regularly due to mineral build up. General maintenance does not need to be performed by the licensed technician.


When there is a problem with the unit, gas tankless water heaters tend to be easier to fix and due to how simple they are they also have a longer life. The lifespan of the average tankless water heater is 20 years, because they are built to be repaired and have individual parts replaced as needed. But, due to the simplicity of design of electric tankless water heaters they tend to have a much longer lifespan than that of a gas unit.

Lifespan Factors

There are a few different factors that affect the life of a tankless water heater. Acidic water, hard water, installation and maintenance.

Should I Choose an Electrical or Gas Tankless Unit?

Electricity is available everywhere, unlike natural gas or propane. This could have a large impact on whether you decide to go with either an electric or gas tankless water heater.

Another factor could be how old your house is. Not all homes have a new enough electrical system to support an electric tankless water heater. More often than not, it is required that a house have a minimum of a 208 volt electrical system.

Will it Meet My Needs?

How much water does your house need? The tankless water heaters output is measured by how many gallons per minute, or GPM, that a unit can put out. In most cases 8 GPM is the standard for an average sized family.

An electric tankless water heater delivers up to 8 GPM and the gas units are capable of producing much more than the 8 GPM. The temperature outside tends to affect the GPM of a tankless water heater.

The colder the water the lower the output. Gas tankless water heaters generally perform much better in colder weather than their counterparts do. For larger families the gas unit is usually the better buy.

Environmental Impact

Electric and gas tankless water heaters also have different impacts on the environment. Many people have increased concerns regarding global warming, greenhouse gasses and the burning of our very precious fossil fuels. Greenhouse gasses are gasses in our atmosphere that absorb and then emit radiation. These gasses eat away at our ozone layer which then depletes the amount of protection we receive from the sun.

We generally do a lot of research into the items we buy and use to make sure that it will have as little impact on the environment as possible. Although electric tankless water heaters have almost no impact on the environment, gas tankless water heaters tend to have quite a large impact on it. Gas units produce greenhouse gasses and burn fossil fuels which in turn has a great impact on global warming and the erosion of our ozone layer.

The Facts


Which is Better?

Ultimately the decision is yours as to whether or not electric tankless or gas tankless water heaters best suit your needs and wants. Both definitely have advantages and disadvantages.

The great thing about tankless water heaters is that they are more energy efficient than your typical tank water heaters. They are also distinctly more compact and provide a constant flow of hot water. But, in the end the electrical tankless water heater would be easier to maintain and they have a longer life span compared to the gas tankless water heaters.

Gas tankless water heaters are definitely better for you if you live where the climate is colder seeing as the gas can heat the cold water better. Make sure, whatever you do, that you have a professional install and maintain your tankless unit.

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