Electric Vs Gas Tankless Water Heater

Updated August 20th, 2022
This article contains affiliate links. If you click on these and make a purchase, we will receive a small percentage of the sale. However, this does not influence our editorial content. You can read our disclosure to learn more.

Being informed about these marvelous water heaters can make all the difference.

Hot water is a household necessity. And for the sake of comfort, cleanliness and convenience, every home should be fitted with a water heater.

Access to water is a fundamental human right, and hot water, especially in cold places, is not just a necessity but a non-negotiable. The entire family’s wellness will hang in the balance if this is not provided.

There’s an overwhelming variety of hot water heaters on the market. You can buy solar water heaters, water heaters that can warm or cool their surrounding spaces, and water heaters that simply use gas fumes from your existing gas system.

Tankless water heaters are highly popular: they’re wonderfully efficient, and surprisingly cost effective for long-term use. In this article, we’re going do an in-depth review of two types of tankless water heaters: gas and electric.

  1. We’re going to compare tankless gas and electric water heaters to see which is the most convenient, efficient and effective type to install in your home.
  2. Then we’ll cover exactly why tankless water heaters are such an excellent buy if you’re needing to install a new water heater.
  3. And right at the bottom of this article, we’ll let you know about our current favorites on the market.

Electric vs. Gas Tankless Water Heater: Our Review

Electric and gas tankless water heaters may be similar in some respects… but they tout some significant differences, too. Here, we’re going look at aspects like installation costs, running costs, flow rates and environmental impact… and figure out which heater is the best buy for your household.

Initial Cost

Purchasing a gas tankless heater will take a much heftier bite out of your bank balance than investing in their electric counterparts. They can cost twice as much.

Electric tankless heaters are also relatively painless to install. They require some basic wiring and plumbing, and no vents are needed. Installing gas tankless heaters, on the other hand, can be quite an involved process.

Non-condensing gas systems need a robust, high quality venting system for feeding the fuel burning process, and for getting rid of fumes. Gas lines often need upgrading in order to accommodate a tankless gas water heater, too. The home’s existing structure generally ends up needing alterations in order to safely install a tankless gas water heater. If you add the cost of the initial purchase to the plumber’s fees and the cost of installing vents and working on the gas lines, gas tankless water heaters can end up requiring an unpleasantly hefty initial outlay of finance.

Lowest initial cost: electric tankless water heater.

Running Cost

In most parts of the world, gas costs less per unit of energy output than electricity.

However, this is not true everywhere, so be sure to compare gas and electricity prices in your area if you’re not sure. Gas prices also fluctuate more dramatically than electricity prices… and are expected to rise in the future.

While gas usually costs less according to power output, electric tankless water heaters are more efficient than gas types. Gas offers an 80-85% efficiency, while most electric tankless heaters tout a stunning 98-99% efficiency. This means that less energy is lost during the heating process if you’re using the electric type. This helps to offset the higher unit cost of electricity.

Overall, for most regions, it’s hard to come to any definite conclusions about which type of heater is cheaper to operate.

Lowest running cost: inconclusive, unless you live in a region where gas is pricier than electricity – then the electric tankless heater costs less to operate.

To be sure, make it a habit to check natural gas rates in your area before deciding to purchase anything. A little research will help reduce your electricity cost in the long haul.


Electric tankless water heaters are small. They can be a third of the size of the gas version, and they can be installed in closets or other small spaces.

In some ways, this is an advantage. In other ways, the modest size and cost of the electric tankless water heaters has significant drawbacks.

When it comes to tankless water heaters, heating ability is measured by GPM: how many gallons per minute of hot water the heater can produce. In a moderate climate, an average-sized household requires around 8 GPM of hot water to cover its needs. Electric tankless water heaters top at a flow of 8 GPM; some offer as little as 3 GPM.

A tankless heater’s GPM is affected by the climate in its location: if the water is frigid when it enters the heater, it’s going to take longer to warm, and heater will ultimately have a lower flow. So, if you’re an average- to large-sized household, and you live in an area where the weather can get particularly icy, there’s a good chance that the small, cost-effective electric type won’t work for you.

Gas tankless water heaters, on the other hand, tend to provide 8 GPM and above. A good unit can provide hot showers to a house full of people in the dead of winter. And there are propane-fueld models available for those who don’t live in places where inbuilt gas systems are available.

If you want a reliably hot shower, a gas-fueled tankless water heater is your best bet.

Most effective: gas tankless water heater.

Environmental Impact

Above, we dug into the energy efficiency of the two types of tankless water heaters we’re reviewing here, and how this affects running costs. Really, this deeply affects the environment, too. The fossil fuels used in so many USA power plants are a finite resource, as is the natural gas used to light up stoves and heaters. It’s crucial to use as little as possible of these resources when we’re running appliances.

So, because the electric tankless water heater has an incredible efficiency of 98-99% (that means that nearly a 100% of the fuel used effectively heats water), it’s definitely the more sustainable option.

On top of that, gas tankless water heaters release greenhouse gasses – made as part of the combustion process – into the environment. So, the gas types are adding, however little at a time, to our current climate change problems.

Least negative environmental impact: electric tankless water heater.


To keep on functioning at full capacity, and to meet safety requirements, gas tankless water heaters require relatively rigorous maintenance. They should be inspected every year by licensed professionals, who can make sure they are still combusting safely and effectively. They tend to get a build-up of mineral scale, which needs to be flushed regularly, and the water inlet screen also needs to be cleaned often (though you can do this bit yourself). If something is wrong with the unit, troubleshooting and repair can take a ton of time and expertise, as these types are quite complex.

Electric heaters, in contrast, are wonderfully easy to maintain: the inlet filter needs a clean whenever it becomes clogged, and once a year, the system needs a flush. Repair is generally straightforward, too, as these units are simpler in design.

Easiest, most cost-effective maintenance: electric tankless water heater.


It’s tough to decide which type of tankless water heater makes for a better buy. Both have strong benefits and significant drawbacks. Here’s what we think: if you can get away with installing an electric unit, you should. Overall, it’s way cheaper; it’s far easier to maintain; it’s environmentally conscious, and takes up very little space.

If you think an electric tankless water heater won’t cover your hot water needs, though, don’t hesitate to install a gas unit. The fastest way to fall out of love with your new purchase would be subjecting yourself and your family to mediocre, lukewarm showers.

Gas Tankless Water Heater: Pros and Cons

Pros Cons
High GPM

 Can service large households in cold weather

 Lower unit cost for fuel (in most locations)


 Installation can require home renovations

 Less energy efficient

 Releases greenhouse gases

 Requires rigorous maintenance

 Should problems occur, troubleshooting can be complex

 Takes up space

Electric Tankless Water Heater: Pros and Cons

Pros Cons
Relatively inexpensive

 Environmentally conscious

 Space saving

 Very little maintenance

 Generally easy troubleshooting and repair

 Doesn’t require venting

 Energy efficient

 Not powerful enough for some locations and households

 Electricity is often pricier per unit of power than gas

Benefits of Using a Tankless Water Heater

There are so many kinds of water heaters on the market… and yet, tankless water heaters remain highly in demand. Here’s why.

  • They’re more energy efficient than most water heaters that use a tank, as hot water on standby constantly loses heat.
  • They save money when it comes to operating costs.
  • They last longer than many other water heaters.
  • Parts are easily replaceable.
  • They take up very little space compared to a heater with a tank.
  • You can have hot water instantly, any time.

Our Favorite Water Heaters

Buyers are currently loving these tankless water heaters. They have excellent reviews online and are going at killer prices.

Gas Tankless Water Heaters

These small gas heaters may not service a large household, but they run on tiny amounts of fuel and come at a steal of a price.

    1. Rinnai V Series HE Tankless Hot Water Heater

    1. Marey GA10LP Power 10L 3.1 GPM Propane Gas Tankless Water Heater

Electric Tankless Water Heaters

These models are slick and smart.

    1. Stiebel Eltron Tankless Water Heater

    1. ECOTOUCH Tankless Water Heater

Portable Tankless Water Heaters

These units are ideal for using in an RV, and can make for a luxurious camping experience.

    1. GASLAND Outdoors BS158 1.58GPM 6L Portable Tankless Gas Water Heater

    1. Eccotemp L5 Portable Outdoor Tankless Water Heater

Mini Tankless Water Heaters

These nifty little units are perfect for heating water for the washing machine, or for installing in the pool house.

    1. 3000W Mini Electric Tankless Instant Hot Water Heater

    1. Rheem 240V 2 Heating Chambers RTEX-18 Residential Tankless Water Heater

2 Replies to “Electric Vs Gas Tankless Water Heater”

  1. I like how you stated that tankless water heaters take up much less space compared to other types of heaters. Since I live in a small and cozy condominium, I feared that I might have no alternatives to the bulky and large heating appliances that other full-fledged houses have access to. However, after reading your article, I now know that looking for a local plumber that can get me a tankless water heater is the way to go so it can fit into my space.

  2. The part of your article that mentioned how little space tankless water heaters take up was really helpful. Living in a condominium limits the kinds of appliances that are available to me, so I figured I should research ones that I can use even in a small living space like mine. With that in mind, I’ll look for any plumbers in the area that can help me get one of these tankless units right away.

Leave a Reply

Your email address will not be published. Required fields are marked *