Electric VS Gas Tankless Water Heater

When building a new house or renovating an old one or changing the old tank style water heating system, we get confused. Which one to pick gas or electric? Therefore, we concentrate on electric vs gas tankless water heater comparison with our options.

Sometimes, we don’t have a say about choosing. Because, we have only one power source with no alternatives. In addition, we can’t buy the one we like. There are many reasons and areas where we can’t have both gas and electricity power source.

However, if you have both options available, then you can compare gas vs electric tankless water heater to get the best according to your needs. We are here to elaborate the benefits of both types tankless water heating systems and the shortcomings you may face using them.

Tankless water heaters usually use either gas or electricity power source. You can decide the gas option into 2 types propene or natural gas. Although, electric and gas models have different designs with similar working procedure. However, natural gas and propene systems have similar design and working mechanics.

Moreover, manufacturers always offer both propene and natural gas models. Many new models can support both natural gas and propene as their power source without changing the design or settings.

Electric VS Gas Tankless Water Heater: Which is Better?

You can’t just decide a better option between these two. Both has their own strength along with some weaknesses too. However, one thing is sure, they are both good and works better than the vintage tank storage water heaters.

You have your own needs and requirements. You have to choose according to your circumstances, not other says or recommended. Moreover, the one good for another family may not be good for your own house.

Choosing a water heater is an important task. Therefore, you should choose based on budget, power source, installation complexity and cost, regular hot water demand and most importantly your personal choices or preferences.

However, after considering all these, if you can’t make a decision, then your best option will be contacting a professional. Even if you make a decision, please consult with a professional before buying. After considering all your requirements and options, the professional will guide you towards the best tankless water heater for your house.

Gas VS Electric Tankless Water Heater: Consideration Factors

While comparing, electric tankless water heaters are visually, technically and functionally different than gas tankless water heaters. Their only commonality is the end products and purpose. That is to say, both are water heaters and produce hot water.

We have consider the below points and factors are important to choose the right water heater. Please read till the end to get all your questions answered. Also, don’t forget to ask a professional after making primary decision.

Unit Price

Without any debate, we can say gas systems are more expensive than electric. They are larger and installing take more efforts and money too. Therefore, based on unit price, electric systems are the best choices. Lets compare:

Gas Tankless System

  • A regular gas tankless water heater usually cost around $1000-$1500.
  • If you add more functionality or features, that will increase cost too.
  • Condensing gas water heaters are expensive than non-condensing system. However, installation cost is higher for non-condensing ones.
  • Condensing heaters don’t use venting. Moreover, have superior designs and functionality. That’s why they are expensive.

Electric Tankless System

  • The regular price range for electric tankless water heaters is $500-$1000. Comparably less expensive than the gas systems.
  • The most sophisticated electric model will cost less than same output gas models.
  • Same price electric models will produce more hot water than gas models.

Installation Cost

Installing a tankless water heater isn’t a piece of cake. Its complicated and required expert hands. Moreover, if you want the desired output while ensuring 100% safety protocol then you must hire a professional.

In addition, many manufacturers ask or recommend clients to use their certified professionals only. The warranty will depend on it.

You are investing a large amount for the heater and installing it. Therefore, you must ensure it is installed perfectly and most efficiently. That will ensure optimal output and better service life.

Gas Tankless System

  • Gas systems have complicated design comparing with electric, therefore installing requires more cost.
  • Although, buying non-condensing system is cost effective but it needs complex and specially designed venting system. It will increase installation cost.
  • This venting system requires category III stainless steel that is really expensive to buy. Thus, increasing the cost.
  • Most times, existing home gas lines and venting aren’t compatible or match with gas tankless water systems. To make them compatible or adding new one will cost more.
  • You have to make change to the current gas lines and venting system. That is an extra cost comes with the new gas on demand water heating system.

Electric Tankless System

  • Electric heaters have simpler design and easy to install process. Therefore, reducing the installation cost drastically.
  • Electric tankless water heaters are smaller size and compact design. So, you can install it on the wall or floor while leaving extra spaces.
  • In addition, electric systems aren’t using any combustion. Therefore, you will need no venting for it.
  • Because of electric systems small size, you can easily install it in closet or other small places. You can also use this compact water heaters on RV where all space counts.
  • Electric tankless water heaters usually use large amount of electricity. Your current home power system may not work well with it.
  • You have to upgrade the power system to be compatible with the electric systems and that can increase the installation cost.

Energy Cost and Efficiency

While operating the water heater, the overall operating cost is based on the fuel or energy cost and how efficiently it is working. We will discuss both the cost and how you can make a decision accordingly.

Energy Cost

Based on the prices of gas for last few years, it costs lower than the average cost of electricity. However, it isn’t true for all states. Because, the price of gas varies in different places. There are some regions where gas prices are higher than electricity price.

For the volatile nature of gas prices, it fluctuates a lot. Moreover, according to the price increase trends, gas price will get higher every year for the foreseeable future. On the other hand, electricity prices will be more stable and will not increase much.


How to calculate the efficiency for a tankless water heater? You may or may not know. Therefore, we will describe it with simplest term. How much hot water is produced and delivered for a single unit of energy cost is the efficiency rate of a heating unit.

If you get gas vs electric tankless water heater efficiency comparison, then electric ones are better. Mostly, electric water heating systems efficiency is around 100% where gas has less than 90%. In other words, gas systems waste more energy than electric systems while producing same volume of hot water.

Gas Tankless System

  • Gas prices are lower so they cost less as price basic for overall energy cost.
  • Moreover, gas prices fluctuate more often. So, month to month energy cost will vary.
  • Some regions have higher gas price. So, those regions gas systems have more energy cost than electricity.
  • Top quality gas tankless water heaters efficiency rate is between 75% to 85%. Therefore, the energy waste will be 15% to 25%.

Electric Tankless System

  • Electricity prices are higher than current gas prices. So, electric tankless systems have expensive energy cost while operating.
  • However, electric systems has a efficiency rate between 95% to 99% so waste less energy. Therefore, the waste will offset the overall cost difference.
  • Some regions electricity prices are lower than gas prices. In those regions, electric systems are more cost effective.

Output Capacity

The water output measured by the number of gallons hot water delivered in every minute or GPM (Gallon per minute). According to research and statistics, average family uses 8 GPM hot water at a time. However, it isn’t a sure rate for you.  So, you must evaluate and determine the average water usage of your family before being sure.

If you calculate wrongly, then you can run out of hot water while using. Moreover, it will become a regular and painful problem for your household. Shower or bath or dishwasher or washing machine takes a lot of water at a time. Therefore, calculating is a major step while choosing a tankless hot water heater system.

The base water temperature also controls the hot water producing rate. Meaning, if the incoming water temperature is low, then the heater will take more time to heat the water to the desired temperature.

So, electric vs gas tankless water heater comparing situation, often gas systems do better at delivering hot water when the volume is large. However, if the desired delivery output is between 3 GPM to 8 GPM, then both work similarly. When, the volume is larger than 8 GPM, gas systems work better than electric.

Gas Tankless System

Gas tankless water heaters are better for large volume of hot water delivery (8+ GPM).

For larger family or family with high volume hot water needs, gas systems are better and more efficient.

When large volume hot water delivered regularly, the efficiency rate of gas systems get higher, meaning less energy waste.

Gas system works better in colder weather where the incoming water temperature is low.

Electric Tankless System

  • Electric tankless water heaters work better than gas systems when the desired output delivery is between 3 GPM to 8 GPM.
  • The output rate will vary depending on the incoming water temperature. The colder the water temperature the output rate will decrease proportionately.
  • In colder weather condition, electric systems works less efficiently comparing with gas systems.

Regular Maintenance

Whether you like it or not, you have to do regular maintenance to tankless water heaters to keep them in perfect condition. These systems require regular and full maintenance to maintain superior efficiency. Moreover, regular maintenance will ensure better and fuller service life expectancy.

Electric Tankless System

  • Electric tankless water heaters require less maintenance comparing with gas systems.
  • The inlet water filter needs regular cleaning. Yearly or monthly as the manufacturers recommend.
  • Lime scale build up is a common problem. To prevent it, you must flush the whole system regularly on yearly basis.

Gas Tankless System

  • Gas tankless water heaters need more regular maintenance than electric systems.
  • Licensed technician must examine the whole system yearly basis. The technician will check the combusting system and safety along with whole unit health signature.
  • Regular mineral scale increasing problem is common problem in gas systems. Therefore, you must clean the interior, and for that regular flushing is a must.
  • You can do the basic maintenance by yourself. However, its always better and recommended to get help from a professional.

Life Expectancy and Warranty

Tankless water heaters have better service life than regular tank storage water heaters. Regular storage tanks have leak and other problems after using for a few years. However, tankless systems can work without problem for 15-20 years.

You can easily repair a tankless system. In addition, you can easily change replace spare parts and these parts are available on most places. Whether its a gas or electric tankless water heater, it will last longer than any storage tank system.

However, there are some factors to consider when you are expecting better service life expectancy for your system. Some factors are easy to follow and maintain. However, some require regular maintenance and extra filter installations. But, without these factors, the service life will be shortened and sometimes the unit will not get any warranty.

Water Acidity

To prevent water contamination, chlorine and ammonia mixed with the water. However, this mixture will increase the water pH level. In other words, water becomes acidic. Its seriously unhealthy and harmful for your skin and hair.

However, the most impact of acidic water is on the home appliances and plumbing. Acidic water destroys and harms those. Plumbing and heat exchanger within the water heaters breaks down and gets ruined by acidic water.

Therefore, you must install a filter to remove the acidity from the incoming water to keep the heater safe and sound. If you have pre-installed faucet and shower water filter, you still need a whole house water system filter installed.

Hard Water

Excessive minerals within the water or hard water can increase mineral build up within the gas tankless water heater. You need frequent flushing to prevent the scale build up.

Installing a water softener for the whole water plumbing is a better option than regular flushing. That is to say, yearly maintenance will be needed if you already have water softener and filter installed.

Proper Installation

Installing the water heater properly is a main requirements for getting optimal amount of hot water with highest efficiency. Moreover, proper installation will ensure highest safety.

Some manufacturers demand only their certified professionals installation to get their warranty. Others recommend highly trained and certified professionals to install the unit. That will ensure and guarantee highest efficiency and safety.

Yearly Maintenance

To increase and retain the service life, all tankless water heaters required yearly and frequent maintenance. Regular flushing will help to prevent lime scale build-up and clean the whole heater system properly.

Gas systems require expert level maintenance yearly and sometimes electric systems also need that. Better to get professional help than doing yourself. It will ensure superior performance along with better life expectancy.

Electric Tankless System

  • Average service life is around 20 years because of its simpler and superior design.
  • Average warranty period for electric tankless water heaters is 5-10 years. But, the warranty vary for parts and labor warranty usually 1 year only.
  • Warranty may require professional maintenance and installation.
  • If any problem occurs, its always easy to diagnose, find, troubleshoot and repair for electric systems.

Gas Tankless System

  • Usual life expectancy for gas tankless water heaters are around 20 years. However, it depends on the maintenance and water quality.
  • With complex design, you will always need expert help while servicing a gas system.
  • Regular warranty period varies from 8 years to 12 years. Moreover, separate parts have separate warranty period. Heat exchanger has the highest warranty, where other parts have 5-7 years warranty and labor only 1 year.
  • Without regular maintenance and bad water quality can seriously harm the life expectancy of the unit. Moreover, less regular maintenance can void the warranty too.

User Choice

The only purpose of gas or electric tankless water heater is to produce on demand hot water as much as needed. They may have different designs and settings. Their working procedures also different too.

However, it all depends on the user. Whether you want gas or electric system, it depends on your preferences only. But we can help you decide by telling what others usually do.

Electric Tankless System

  • If you consider safety above all else, then electric systems are better than gas systems.
  • Some people don’t like natural gas or propene and they hardly use them. For those people, electric systems are better.
  • If you want eco-friendly system, then electric ones are for you. They don’t use fossil fuels and do no emissions.
  • Electric systems are more efficient and less costly to buy and maintain.

Gas Tankless System

  • If you are changing from traditional storage tank water heaters, then gas is the better option for you. You already using one gas system, the new system is only tankless others are quite the same.
  • With a larger family with high demand of regular on demand hot water, then gas systems are for you.
  • Electric ones can’t provide more than 8 GPM hot water at a time. Moreover, the flow rate will be less on colder weather condition. Therefore, for more and frequent high flow hot water, gas system is better for you.

Energy Types

You are investing a handful amount to install a tankless water heater. In addition, with proper and regular maintenance and care, the system can run around 20 years or more.

Therefore, you must consider the fuel or energy source of the unit and how the price can fluctuate around that time. Otherwise, current cost efficient unit can become a white elephant for you after 5-10 years.

Electric Tankless System

  • Current electricity price is higher comparing to gas. However, according to research and trends the price will not go very high in next years.
  • Sometimes, old homes don’t have proper electric connection or capacity to install the high power using electric tankless water heater.
  • You may need to hire an electrician to upgrade the electric connection. You must remember, this will significantly increase the overall installation cost.

Gas Tankless System

  • Current gas price is significantly lower than electricity price. But the price fluctuate regularly and more often than electricity price.
  • In addition, some regions gas prices are equal or more than electricity price. You have to keep that in mind too.
  • There isn’t any guarantee the price for gas will be this low. Many economists suggest that the price will be 2-3 times more in the next 10 years only.


We all know gas is fossil fuel and it emits harmful substances in the air. Where electricity is 100% ecofriendly. It doesn’t emit anything and have no hand in global warming. Moreover, if you can spend the energy efficiently, it will save you hard cash along with environment also.

Electric Tankless System

  • Electric systems are highly efficient. Their efficiency rate is around 95% to 99%.
  • Based on the cost, this efficiency level is very good and will save a lot of energy and cash.
  • They doesn’t do green house gas emission or help global warming. In fact, it helps preventing global warming.

Gas Tankless System

  • Comparing with storage tank water heaters, gas systems are more energy efficient and better performing.
  • Their energy efficiency level is around 80% to 89%, not bad for any gas powered appliance.
  • However, these systems emit regular green house gases thus polluting the air and helping global warming.

End Words

As we have described previously, both are good systems. So, there is no clear winner between gas vs electric tankless water heater debate. You can pick anyone or none, it all depends on your situation and preferences.

Everyone has their own condition, preference and other important factors to consider. What is a good choice for your friend or neighbor can’t automatically be a good fit for you.

You should consider your preferences along with your home conditions and the volume of hot water you need. After that, consult with a professional for guidance. Then you can get a clear answer.

If you are currently using eclectic system, then its better to get new one electric too. However, if you have storage tank system, then converting into gas system is best for you. Do your calculation according to your circumstances then you will get the proper tankless water heater for your house.