Everything You Need To Know About Tankless Water Heaters 

 August 17, 2020

By  Jacqui Cheng

If you’re in an area of the world where you have soft water, you may find that your water heater has given in long before its warranty. This is because this type of water is much harsher on water heaters.

That being said, if it has been a while since you last replaced your hot water tank, you will be happy to know that there are now a variety of more cost-effective and energy efficient types to choose from, and this includes tankless water heaters.

Because water heating equates to approximately 20% of a home’s energy costs in some parts of the world, it is important to choose a model that will not send your household bills skyrocketing.

While many modern models are more expensive than their earlier designed counterparts, they were created with the aim of being more efficient.

According to the new results of energy efficiency standards, water heaters that are 55 gallons or more could cut your utility bills by anywhere between 25 and 50% while those smaller than 55 gallons will only see a 4% boost in energy efficiency.

While it is important to consult a professional in order to not only understand the new regulations but also choose the best model for your home, we have created this comprehensive guide in order to help you with the basics.

In it, we will tell you everything you need to know about the various types of water heaters available, specifically tankless ones. We’ll tell you about the pros and cons of using a tankless water heater, and share some information on some of the best manufacturers in the industry today.

Lastly, we’ll give you some tips on how to maintain your tankless water heater and share some information on the installation process. So, without further ado, let’s get started.

What Are Water Heaters?

Water heaters are familiar mechanisms in most peoples’ homes across the U.S. and other parts of the world where it is colder or where hot water is needed for cleaning and cooking.

Traditionally, they come in the form of big metal cylinders or tall drums. These can be placed virtually anywhere in a home but are normally found in the laundry room, basement, a hidden cupboard, or in the bathroom.

While traditional water heaters are basically drums filled with water and equipped with a heating mechanism across the side or the bottom of them, newer models come equipped with a variety of interesting features.

No matter which type of water heater you look at, these huge mechanisms are amazing because they send hot water directly to your faucet with minimal effort.

While these appliances look simple, they come packed with a highly complex and intelligent mechanism that allows them to function as such, but we’ll go into that a little later.

The Various Types Of Water Heaters

As mentioned above, there are a huge variety of different types of water heaters now available to choose from, all of which come with their unique set of features and benefits. Here are some of the most common ones:

Storage Water Heaters

Storage water heaters, also known as storage tanks, are the most common type of water heater found worldwide. As the name suggests, a storage water heater stores hot water in an insulated tank until the water is used.

These tanks come with pressure-relief and temperature valves which open if either exceed the levels that you originally set. These types of water heaters can either use gas or electricity.

Gas ones are normally more efficient from both an energy and price point of view. That being said, they’re normally more expensive to buy in the first place.

Tankless Water Heaters

As the name suggests a tankless water heater does not have a tank. These water heaters heat water when you need it without having to reheat an entire tank to provide hot water.

These mechanisms can also be installed on a single point of use meaning that you can heat the water for your shower separately to that of your sink and so on.

Also referred to as on-demand water heaters, these mechanisms can be installed virtually anywhere in your home, including a closet or an exterior wall.

Combination Systems (Water And Space Heating)

Typically gas-fired, these types of water heaters provide heat to both your water and your space. Combination systems are particularly popular in multi-unit housing because they can provide metering for tenants for both space and water.

These systems are known for lasting longer because the water circulates more regularly thus reducing the amount of sediment on the bottom of the tank.

What Are Tankless Water Heaters?

As mentioned above, tankless water heaters are those that do not use a tank to provide hot water. These mechanisms give you an endless source of hot water in an energy and cost-efficient way because they do not heat a whole tank every time you need hot water.

One of the biggest reasons that tankless water heaters have become increasingly popular is because they provide an endless flow of hot water.

While some models need to be installed throughout your household at multiple point of uses, others come as part of larger centralized models giving you all the necessary hot water for your home.

While they are more expensive to purchase in the first place, the energy saving opportunities are huge meaning that they pay for themselves within just a few years.

Advantages Of Using A Tankless Water Heater

Tankless water heaters come with their own set of unique pros, here are the most obvious ones:

Endless Hot Water

Because tankless water heaters dispense hot water on demand and don’t need to reheat a tank to function, you’ll never run out of hot water.

They’re particularly useful for larger households and if you’re thinking of upgrading your water tank to a larger one, you may want to consider a tankless water heater.

Space Saving Design

A Tankless water heater is significantly smaller than more traditional units. These mechanisms are wall mounted and therefore do not have to be stored in your attic or bathroom. Some units can even be installed outdoors.

Higher Quality Product

One of the biggest advantages of using a tankless water heater is that it will last you nearly a lifetime. Traditional water heaters have a lifespan of anywhere between 12 and 18 years whereas tankless ones can go for anywhere between 20 and 30 years.

Because they are relatively new, tankless water heaters are designed with the highest quality materials and components, thus making them less likely to leak or rust.

More Energy Efficient

Traditional gas water heaters operate at less than 70% of their ability whereas tankless ones operate at more than 80%. Aside from this, a tankless water heater does not waste energy heating, reheating, and cooling water in the tank.

Last but not least, because of their lack of tank, your water heater will not lose its efficiency because it won’t fall victim to an overload of sediment.

Disadvantages Of Using A Tankless Water Heater

Here are some of the major disadvantages of tankless water heater:

Higher Upfront Cost

One of the biggest problems with choosing a tankless water heater is the initial upfront cost. They are significantly more expensive than their more traditional counterparts.

That being said, thanks to their long lifespan and increased efficiency, you can expect to make up the difference in energy savings.

Special Venting Requirements

Aside from their higher upfront cost, tankless water heaters have higher-powered burners. This means that they need special vents in order to fully function, something that only professionals know how to install, thus adding to the overall cost.

Hotter Water Than Necessary

Tankless water heaters tend to dispense water that is significantly too hot for most households. Aside from the higher costs, this means that you may need to install a cold water mixing valve to avoid burning yourself.

How Do Tankless Water Heaters Work?

As mentioned above, tankless water heaters do not use a tank to produce hot water in a home. They can come either gas powered or electric, both of which use a similar mechanism to function.

With a tankless water heater, once the tap is turned on to produce hot water, cold water travels through a pipe into the unit. Then, either an electric element or gas burner heats the water that passes towards your taps.

Simply put, the boiler heats the water that warms your home, that water then heats the coil, thus producing hot water throughout your taps.

The Difference Between Gas And Electric Tankless Water Heaters

Despite the fact that many do not have the luxury of choice because of a lack of electrical power or access to natural gas or propane, others can. Unfortunately, making a final choice can be challenging.

There is no simple way to choose between these two types of tankless water heaters, a key reason why we’ve provided you with a brief comparison of the two below:

Electric Tankless Water Heaters

Electric tankless water heaters offer good quality, virtually instantaneous hot water and normally cost anywhere between $500 and $1000 per unit’ although some can be more expensive.

Aside from their moderately low price, electricity costs are known for being more stable and are cheaper to run than propane models in some parts of the world.

In order to install one in your home, you must be able to confirm that you have the adequate electrical services for the model you choose.

They typically offer a flow rate of up to 8GPM in warm climates and anywhere between 3 and 3.5GPM in colder climates and during the winter months.

They have a lower carbon footprint because they do not emit any greenhouse gas emissions and because of their small size, they are more sustainable to manufacture and dispose of once their lifespan is up.

Electric tankless water heaters do not require any maintenance and can be installed virtually anywhere in your home because they do not need any venting.

Gas Tankless Water Heater

Slightly more expensive than their aforementioned counterparts, gas tankless water heaters cost anywhere from $1,000 and upwards per unit depending on the brand and model you choose.

In addition to their higher initial cost, they do require a certain level of venting which further increases the overall cost of your device as you’ll have to pay a professional an installation fee.

Not only this, before you can install your system, you will have to confirm the gas line size, the venting options, and the fresh air supply.

While the above is true, natural gas is slightly cheaper to operate at the moment despite projections saying that these prices are likely to rise. These devices do also produce greenhouse gases and tend to increase the world’s reliance on fossil fuels.

Lastly, gas powered tankless water heaters do require annual maintenance in order to live through their expected 20+ year lifespan and they have a flow rate of 8GPM or more in warm climates.

Tankless Water Heaters And Energy Efficiency

While the initial cost of a tankless water heater is higher than traditional models, these devices are extremely energy efficient. In fact, according to Energy.gov, homes that use less than 41 gallons on a daily basis can be more efficient by anywhere between 24 and 34%.

For homes that use more hot water, approximately 86 gallons per day, tankless water heaters can be more efficient by anywhere between 8 and 14%.

And, if that’s not enough, by installing a tankless water heater at each hot water outlet, you’ll be able to save anywhere between 27 and 50% on energy.

Lastly, a tankless water heater can last more than 20 years without any maintenance whatsoever if you opt for an electric model.

Plus, the parts are very cheap meaning that despite the larger initial financial investment, you’ll have a product that will last you a short lifetime without incurring you any additional fees along the way.

Reputable Tankless Water Heater Manufacturers

Now that you know everything you need to know about tankless water heaters, here is some information about some of the most reputable manufacturers in the industry:


Founded all the way back in 1920 by Hidejiro Naito and Kanekichi Hayashi, Rinnai is focused on providing households across the world with comfortable lifestyles through heat.

With innovation and improvement at the forefront of the company’s ethos, Rinnai creates quality products through in-house design, engineering, and manufacturing.

Thanks to Rinnai’s passion for customer satisfaction, the company has continued to produce some of the most unique water and home heating gas appliances in both the commercial and residential sectors.

All Rinnai’s factories are ISO 9001 and ISO 14001 certified allowing them to distribute quality products across North America. Plus, you can find the company’s products in Canada, all of which have been approved by the Canada Standards Association (CSA).


The family founded company was started by brothers Donald and Richard Rheem in California in 1925.

Since it’s beginnings, Rheem has been manufacturing a huge variety of products, some of which include household appliances, semi-conductors, and musical instruments, among others.

Today, Rheem is the largest manufacturer in North America of heating, cooling, water heating, pool and spa heating, as well as commercial refrigeration products.

Rheem has won a huge variety of awards, including the 2015 Hot Product Award by Green Builder Magazine, the 2015 Finalist position at the Golden Mousetrap Awards, and the 2015 AHR Expo Innovation Award Honorable Mention by Software, just to name a few.


For more than 100 years, Bosch has been one of the leading global suppliers of services and technology in the Industrial Technology, Consumer Goods, Automotive, and Building Technology sectors.

With foundations dating back all the way to 1886, Bosch now has more than 300 subsidiaries in more than 150 countries. Since its beginnings, Bosch has been building products with the aim of improving its customers quality of life.

Bosch produces a huge variety of heating systems, including tankless models, both point-of-use and electric. Bosch Thermotechnology is committed to creating innovative and efficient products that work together as integrated systems in a sustainable way.


With more than 60 years in the business, Takagi hot water solutions are sold by plumbing wholesalers and contractors alike. Dedicated to creating diverse and high-quality products, the company creates both residential and commercial tankless water heaters.

With safety, quality, customer support, and efficiency at the forefront of everything it does, the company is the first to specialize in tankless-only solutions in North America.

Not only was Takagi is the first company to offer a tankless product with a thermal efficiency rating of up to 95%, but it was also the first to offer a “direct vent convertible” and to utilize the air-fuel ratio rod to maximize safety.


With ETL certification to UL 499, EcoSmart is another company that produces exceptional tankless water heaters in North America and further afield. With a specific focus on water heating, EcoSmart is dedicated to producing and distributing quality green energy products.

In addition to the above, the company aims to save customers money through its patented self-modulating technology which is proven to have the ability to save customers a whopping 50% on their water heating bills.

Today, EcoSmart is available through a huge variety of retail partners in the West Hemisphere including ACE Hardware, Home Depot, True Value, Do It Best, and Orgill, as well as online retailers such as Amazon.

Installing A Tankless Water Heater

First and foremost it is important that you do not try to install a tankless water heater on your own if you do not know the basics of DIY.

With a gas tankless water heater, you first need to find out what the size of your gas main is from your gas company. You should also read all manufacturer’s instructions twice over before getting started.

Normally, tankless water heaters require a larger diameter gas supply line, as well as a higher voltage power supply if you’re opting for an electric model, and a larger diameter exhaust system.

These are the minimum requirements to take into consideration if you’ve opted to install your tankless water heater yourself. Once you have all the right tools and information, you must:

Prepare For Installation

Before you can start you must cut off the main incoming water line to the house. Also, disconnect the supply line from your old water heater and make sure you place a bucket underneath the pipe as leftover water will certainly fall out.

In addition to disconnecting the water and supply line, disconnect the heat source from the old water heater. For a gas or propane model, you must ensure the supply valve is closed. For electric models, simply unplug it from the outlet.

Check For Clearances

Once you’ve disconnected your old water heater, you must ensure you dispose of it according to your local legislation.

Not only this, you must make sure you have all the appropriate clearances to install your new tankless water heater according to state building codes as well as those in your area.

Mount Your Tankless Water Heater

Use the manufacturer’s instructions to mount your tankless water heater on the wall. With a gas model, you must ensure that you install the ventilation ducting. These normally require a larger or stainless steel flue.

Once appropriately mounted, connect the water and gas lines, or if you have an electric model, connect the water line and plug it in.

Final Checks

Once you have connected everything to all the mains lines, double check everything. Also, read through the manufacturer’s instructions one final time in order to light the pilot on the gas water heater and to ensure you have not forgotten any crucial steps.

Cleaning And Maintaining A Tankless Water Heater

Your tankless water heater will come with a clear set of manufacturer’s instructions that you should follow in order for your device to work as intended for the intended amount of time. That being said, here are some clear basic instructions you can follow for most models:

Prepare For Cleaning

Start by turning off the power source and removing the lid from the water heater with a screwdriver. Then, close off the water valves supplying the water. You should also remove the purge port valve caps located on each of the cold and hot water valves.

Use Vinegar Mixture

Once you have prepared your tankless water heater for cleaning attach lines to the valves- these are normally provided by the manufacturer. Then, open the purge port valves twisting them to the same position as the cold and hot valves.

From there, you can use undiluted white vinegar to clean your tankless water heater. Be sure to flush and drain the mixture as per your manufacturer’s instructions. Be sure to replace the purge port valves once everything is clean.

Clean The Filter

Once you’ve made sure that everything is tightened back into place, remove the filter and clean the screen with tap water. Then, screw it back where you found it.


As you can see, a tankless water heater is a complex device that can offer households and commercial establishments alike a mound of space and money saving benefits.

If you’ve decided that a tankless water filter is what you need, then we recommend you head over to our buying guide where we’ve highlighted some of the best electric and gas models on the market today.

Jacqui Cheng

Your Signature

Leave a Reply

Your email address will not be published.

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Subscribe to our newsletter now!