Electric vs Gas Tankless Water Heater: What’s the Difference?

Are you interested in getting a tankless water heater for your home? Torn between an electric and a gas model? Settling for one may not be easy, especially if living in a locality where both options are available.


According to the U.S Dept. of Energy, a water heater is responsible for about 18% of energy use at home. Therefore, ensuring that you have the most efficient heater can save you a lot of money every month.

Different water heaters come at different prices. This means that when choosing between an electric and gas heater, you also need to factor in the cost.

In this post, we compare electric and gas water heaters to help you make a wise buying decision. Read on to learn more.

Electric Water Heaters

Electric water heaters use a heating element to heat the water. These heaters take up less space than the gas water heater. Also, since they don’t produce harmful gases, you don’t have to purchase expensive water heaters.

Electric tankless water heaters boast high-efficiency ratings and deliver roughly 8 gallons of hot water per minute. They have a long life span and are safer than gas in case of fire.

 A tankless water heater might not be the best deal for a big household but works great for a couple or single persons. And, if living in a place that experiences frequent power outages, an electric tankless heater might not be the best option for you.

Gas Water Heaters

Gas water heaters use natural gas to heat water. They deliver a lot of hot water instantly – produce more hot water than electric heaters hence ideal for bigger families.

And unlike with electric heaters, where you can’t have hot water in case of a power outage, you can have hot water even if the power goes out when using a gas water heater.

These heaters have a long lifespan but require regular inspections by a professional. They are also prone to mineral buildup and thus require flushing from time to time.

Electric and Gas Tankless Water Heaters: Key Points

Upfront Cost

To get the difference in price right, you need to factor in the cost of the water heater and the installation price as well.

Gas water heaters are slightly expensive than electric models. A high-quality gas tankless water heater costs roughly $1000 upfront.

Should you choose to get the non-condensing model, you’ll pay less upfront fees but more on installation.

Condensing tankless systems don’t require venting but since they come in sophisticated designs, expect to pay on them.

Electric tankless water heaters are less expensive than their gas counterparts are. You can actually get a high-quality one at $500.

Ease of Installation

Electric tankless water heaters are easier to install, resulting in less expensive installation costs. They are smaller than tankless gas units and require no ventilation.

Thanks to their compact nature, these water heaters are less complex than gas units and can be installed in closets.

And as aforementioned, these systems don’t require venting; hence cheaper to install.

On the other hand, gas tankless water heaters are more complicated and expensive to install. Venting these systems is never easy since many homes’ existing venting ducts and gas lines are incompatible with the units.

Therefore, you’ll have to pay for extra home modifications to accommodate the venting and gas requirements.

Operating Costs

The overall operating costs of a tankless water heater are determined by the cost of fuel and how efficiently the unit in question uses the fuel.

Although the fuel price is usually lower than that of electricity, it’s subject to fluctuations. While the cost of electricity remains relatively stable, gas prices increase significantly.

One thing to note is that most regions experience high gas prices, a fact that makes tankless gas systems more expensive to operate.

Electric tankless water heaters have an efficiency rating of 98 to 99%. Therefore, case of high electricity costs, the efficiency of these systems offsets the high fuel prices.

Hot Water Output

Electric tankless water heaters deliver up to 8 gallons of water per minute of hot water. Gas tankless systems can deliver over 8 GPM and thus the best for larger households.

Note that the temperature of the incoming water highly impacts the output of both systems. The warmer the incoming water, the higher the GPM and vice versa.

Fuel Prices

When purchasing a tankless water heater, you need to consider the impact of future fuel price fluctuations on electric and gas units.

For instance, you need to note that gas prices fluctuate from region to region. And even when gas prices are low, there’s no guarantee that they won’t increase in the future.

Electricity prices aren’t subject to frequent fluctuations.


To keep your water heater operating at its peak, you need to clean it regularly. And while electric systems require minimal maintenance, their counterparts need more maintenance.

You need to get a licensed electrician to inspect your gas tankless water heater to ensure that it’s working as required.

Gas tankless systems are also prone to scale buildup hence the need to check on them.


Electric tankless water heaters have a very long lifespan (more than 20 years) thanks to their simplistic design. Warranty varies from brand to brand, but most boast a 5 years warranty on parts a 1-year warranty for labor.

On the other hand, gas systems come with a 5-years warranty for parts, a 10-year warranty on the heat exchanger and 1-year for labor.

Environmental Impact

Electric tankless water heaters are energy-efficient and don’t burn fossil fuels. They, therefore, don’t pollute the environment in any way(source).

Gas-fueled systems reach about 80% energy efficiency and emit greenhouse gases into the environment.

What Is the Difference Between Electric vs Gas Tankless Water Heater?

Feature Electric Tankless Water Heater Gas Tankless Water Heater
Upfront cost Expensive More expensive
Ease of installation Easy to install and less installation costs. A little difficult to install and higher installation costs.
Operating costs Low operation costs High operation cost
Energy efficiency More energy-efficient Energy-efficient
Hot water output Produces 8 gallons of hot water per minute Produces more than 8 gallons per minute
Fuel prices Not constant – are subject to fluctuations Rarely fluctuate
Maintenance Easy to maintain Require regular maintenance
Warranty 5 years for parts and 1-year for labor 5-years for parts, 10 years on the heat exchanger and 1 year for labor
Environmental impact Environmentally safe Emit greenhouse gasses into the environment.


Q. Which is better, gas or electric tankless water heater?

Electric tankless water heaters are better as they are more efficient than gas systems. They are also less expensive to install and easy to maintain. However, a gas-fueled system is the best if you have a large family as it has a high hot water output.

Q. What is the downside of an electric tankless water heater?

Electric tankless water heaters are more expensive to run. They also don’t have a higher hot water output hence not suitable for larger households.

Q. Are electric tankless water heaters worth it?

They are worth it. Electric systems use less energy saving and can thus save you hundreds on bills. They are also easy to maintain and eco-friendly.

Q. Can you run out of hot water with a tankless water heater?

The only time you can run out of hot water when using a tankless water heater is if you run out of water or fuel to heat it.

Q. Is it cheaper to have a gas or electric water heater?

It’ll depend on your locality. But generally, gas water heaters are cheaper to operate than electric.

Q. Do electric water heaters use a lot of energy?

Electric water heaters don’t use a lot of energy. They run for 3 to 5 hours per day which will cost you about $1.56 per day and $46.81 per month.
And if using a tankless electric water heater, the cost will be less since these only produce hot water on demand.

Q. Do tankless water heaters use more electricity than regular water heaters?

No, tankless water heaters are more energy-efficient than regular heaters. They can be 24 to 34% more efficient than regular models for homes that use 41 gallons of hot water daily.

Q. Should I turn off tankless water heater if the water is off?

You don’t need to shut off your water heater if the water is off as it is not made to heat continuously.

Q. Do gas-powered heaters need electricity?

Gas-powered water heaters don’t need electricity as they don’t use it as fuel.

Q. Do gas or electric water heaters last longer?

Electric water heaters last longer than gas water heaters.

Q. Why is tankless water heater installation more expensive?

Installation of a tankless water heater is expensive because the process involves a lot of activities. For instance, you have to remove the old system, install a new gas line or power outlet; you might also be forced to open some walls or ceilings to install gas lines, among other things.

Q. What size breaker do I need for a tankless water heater?

A standard tankless water heater requires a 40 to 50-amp breaker.

Q. How many amps does an electric water heater use?

Most electric water heaters use 18.8 amps.

Q. What size tankless water heater do I need for a family of 4?

For a family of 4, you need an 8 to 10 GPM gas tankless water heater or a 20 to 28kW electric tankless water heater.

Q. How many showers can a tankless water heater run?

A tankless water heater can run 2 or 3 showers simultaneously.

Q. What is one disadvantage of a whole house tankless water heater?

The main disadvantage of tankless water heaters is that they come with a high price tag. Some cost 3 times more than a tank water heater.

Q. What are the advantages of a tankless electric water heater?

Electric tankless water heaters are easy to install, compact, don’t require ventilation, more energy-efficient, have a longer lifespan and are environmentally friendly.

Q. What are the drawbacks of a tankless gas water heater?

Gas tankless water heaters require more maintenance and annual inspection, are prone to scale buildup and are hard to install.


Both electric and gas tankless water heaters work great when it comes to functionality. However, if yours is a small space, an electric system will suit you best. The units are compact enough to fit in tiny spaces.

Electric tankless water heaters also require minimal maintenance, are easier to install and less expensive.

Gas systems have their place too. Although their installation cost is slightly higher, the lower price of natural gas makes up for it. They have a high water output hence the best for large households.

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