7 Types of Water Heaters Explained

While winters can be entirely fun and enjoyable, we cannot overlook the woes of the chilly weather conditions. That’s why an efficient water heater is an absolute necessity.

There are several different water heater models available on the market, and it’s important to choose something that’ll perfectly meet your needs. So, to make things easier for you, we have put together a list of 7 types of water heaters and explained everything that you need to know about them.

Also, you can look for models with specific features to streamline household chores and any other application that demands warm water. Overall it’s the experience that counts as you’d want a machine that does the job without fail.

Without further ado, let’s get down to business.

Types of Water Heater

Traditional Storage Tank Water Heater


Storage tank water heaters are standard in most homes, and they can run on a variety of fuel types. These tanks are mainly designed for domestic purposes and, as such, are quite reliable.

How Does A Storage Tank Water Heater Function?

This system allows you to store water that needs to be heated. Therefore, the bigger the tank, the more water it can hold. Hence, the tank’s size is critical to the overall efficiency and functionality as it determines the quantity of hot water available at once.

These units typically come with superior insulation that keeps the water warm even after the heater is turned off. Also, they feature 2 valves, where one controls the temperature while the other maintains pressure.

The former opens when the water temperature reaches 120°F, thereby releasing the heat and moderating the temperature level. Meanwhile, the pressure control valve opens to bring down the pressure after it reaches about 150 PSI.

  1. Tankless Water Heater


As the name suggests, this water heater system functions without a tank. The unit includes coils that heat up when filled with water. The coils instantly transfer the heat to the incoming water. This mechanism allows you to access warm water on-demand.

Such a system is suitable for large families as it takes negligible time to heat water. You can choose from the different sizes available and find something with the right capacity. Small size heaters may struggle to cater to a large family. You’ll end up getting cold or lukewarm water. However, with these units, you can also use gas as a power source.

On the contrary, if you’re opting for a larger system, you’ll need a gas line, providing sufficient power to run the heater. Likewise, you can also find larger models that run on electricity, but the heavy power consumption will spike up your bills. Therefore, it’s going to be quite expensive if you’ll be using the heater frequently.

What Type Of Maintenance Is Required?

While tankless water heaters are convenient and efficient, they do require some basic upkeep. A yearly cleaning session is a must to avoid corrosion. Over time, the heater parts develop mineral scale deposits, which could impede proper functioning.

Some heater components are difficult to clean, so you might want to hire a professional for a thorough job. The right maintenance will extend service life, and you can use it for at least 8 to 10 years.

Advantages Of A Tankless Water Heater

A tankless water heater is an excellent option for homeowners looking to reduce energy consumption. Since it provides warm water almost immediately, you don’t have to wait or run the machine for long. Therefore, it’s convenient in homes with multiple users, providing hot water throughout the day.

Downsides Of A Tankless Water Heater

Buying a larger model could increase operational costs as, in that case, you’ll need a separate gas line. The installation and the renovation work simply adds to the overall expenses.

  1. Heat Pump Water Heaters


Also known as hybrid electric water heaters, the heat pump water heaters are the way to the future. If you’re looking to cut down on your bills, we recommend installing one of these units. It reduces power consumption as it does not generate heat directly but adopts a unique mechanism to get the job done.

How Does The Heat Pump Water Heater Work?

As mentioned earlier, the heat pump water heater has a special mechanism that’s unlike any other systems on this list. Long story short, it traps heat from either the ground or air and then uses it on the water.

Therefore, the unit consumes electricity only when the heat from the air or ground is transferred to the water. It’s unlike any other system where the appliance runs on electricity entirely.

Long story short, it uses about 60% less energy compared to other conventional water heater models. However, with these units, the heat pump is placed above the water heater, so you’ll need a vertical space of about 8ft to install the system.

What Type Of Maintenance Is Required?

Like conventional storage-tank water heaters, this machine, too, includes a tank, meaning it has to be cleaned regularly. We suggest undertaking general inspection and cleaning at least twice a year to maintain proper functioning. That should be enough to ensure hassle-free operation for several years.

Advantages Of A Hybrid/Pump Water Heater

When it comes to return on investment, the heat pump water heater ranks higher than traditional options. It’s highly energy-efficient and the ideal system to lower your utility bills.

Downsides Of A Hybrid/Pump Water Heater

All things considered, the hybrid water heater is not a practical option in areas with extremely low temperature. This is simply because it derives heat from the air or ground around it.

Therefore, it’s best not to install the machine in your basement or any place inside your house that experiences freezing conditions. Lastly, these models are among the most expensive options available on the market, which could be an issue for some buyers.

  1. Condensing Water Heater


This is another option that scores high on energy efficiency, delivering a smart heating solution to users. This heater taps the extra gas fumes inside your home and uses it to warm up the water.

How Does The Condensing Water Heater Operate?

These systems are also commonly known as condensing boilers. That said, condensing water heaters are suitable for homes that run on natural gas as a primary source of power.

As for its operation, this system can capture heat from flue gas and then store it for pre-heating the water which enters the boiler. Therefore, it can take care of your needs without increasing the power bill.

It comes with a tank, just like every other traditional water heater. The only difference is that the condensing system traps the hot exhaust gas expelled through the flue, using it as an energy source. Thereafter, these fumes are passed through the coil placed at the base of the unit.

The coil is intuitively positioned in the bottom to heat the incoming cold water. We suggest investing in this model if your household requires about 55 gallons of hot water or more. Compared to other water heaters on our list, this unit has a low energy consumption rating. Nevertheless, make sure to buy the right size and capacity based on your family’s needs.

What Sort Of Maintenance Is Essential?

This model also comes with a tank, just like the other water heaters. So, you should ensure that you get the tank cleaned at least once a year. And, the same goes for the gas import valves that should be maintained well.

Advantages Of A Condensing Water Heater

For homes that depend on natural gas, this water heater model is undoubtedly the most energy-efficient choice. You’ll get abundant hot water as the unit comes with a high capacity tank. Thus, you won’t be running out of hot water soon.

Disadvantages Of A Condensing Water Heater

The main issue with these systems is the lack of compact size. Therefore, it’s only feasible if you have a requirement of 55 gallons or above. Furthermore, any house that does not depend on natural gas has no use for such machines. In that case, it’s best to settle with a conventional storage-tank water heater.

  1. Combined Space and Water Heating System


The combined space and water heating units are suitable for homes with low requirements. The low demand is mainly because of limited air leakage, sufficient insulation, and proper use of the space. As the name suggests, these specialized units are perfect for your household water and space heating, allowing you to cut significant expenses.

How Does A Combined Space and Water Heating System Work?

Also called the ‘combi’ system, this model is the perfect replacement for your outdated water heater and forced-air furnace. To explain further, it combines an optimized hydronic air handler and a high-efficiency water heater to enable this dual function.

The air handlers feature large coils that support heat transfer for rapid and efficient space heating. Usually, the fan coil is installed with the ductwork, facilitating high performance from the get-go.

Meanwhile, the small pump included in the system circulates water from the boiler and the fan coil. So, if you want radiant or floor heating, you can distribute the warm water via the in-floor piping.

When buying the ‘combi’ water heater, make sure to get the right size so you can make the most of the two functions. Since the unit’s operation is different when used for heating water and space heating, the results may also vary.

What we mean to say is that the performance of the space heating component should not be used as a standard to measure the viability of the water heater function, and vice-versa.

What Sort Of Maintenance Is Involved?

Preventive maintenance of the heating system goes a long way in extending equipment life, reducing power bills, and limiting the chances of malfunction. It not only ensures safer operation but also saves you from costly repairs. That said, we suggest getting in touch with an expert at least twice for professional inspection and cleaning.

Benefits Of A Combined Space and Water Heating System

Let’s just say that the ‘combi’ system has the same level of gas consumption as a separate high-performance water heater and natural gas furnace used simultaneously. Therefore, you can save money and avoid the hassle of buying and maintaining two individual systems.

Furthermore, this model prevents spillage from the natural draft appliance, thanks to the direct or powered combustion vent.

Negatives Of A Combined Space and Water Heating System

The initial cost for this machine can be a burden for some users. Other than that, the installation is quite a task, as not all professionals are familiar with this system.

Therefore, the installation of this specialized system is not comparable to the standard method of setting up power vents or condensing water heaters.

  1. Combined Space And Water Heating System With A Hydronic Boiler

Unlike the previous option, this combined space-water heating appliance comes with a hydronic boiler instead of a water heater. It’s a compact, user-friendly and energy-efficient system for a home if you’re aiming to reduce energy consumption and the number of necessary appliances.

These systems are available in different configurations. While some models allow you to heat space and water simultaneously, with others, the functions can be executed one at a time.

How Does A Combined Space-Water Heating System with a Hydronic Boiler Operate?

These types of heating devices are alternatively known as segregated heating systems or combi-boilers. They use a hydronic boiler, which acts as a heat source, and the energy is transferred to the water, usually via a heat exchanger.

You’ll be surprised to find out that in certain countries, there are rules that state the need for a double-wall heat exchanger for such heating techniques. Basically, this ensures there’s no cross-contamination between potable water and water in the boiler heating loops.

You can opt for the latest combination boiler model that offers full-energy saving power along with a tankless design. This makes sure that there is no chance of unnecessary water heating when you’re away.

Additionally, the system includes a flow control valve that maintains a constant temperature level irrespective of the incoming water temperature. Meaning you can enjoy an abundant flow of hot water with the right temperature setting.

What Type Of Maintenance Is Required?

Like in most other cases, you should undertake annual inspection and cleaning sessions to ensure that the boiler is in top shape. Besides, the flow control valve and auxiliary pump connections should be properly maintained to prevent the occurrence of corrosion and mineral accumulation.

Benefits Of A Combined Space-Water Heating System?

Generally, these heating systems have a lifespan of around 10-15 years, depending on the overall maintenance and use. Also, it has a compact, space-saving design with built-in parts for auxiliary pump connections, outdoor reset control, and recirculation function. Thus, you don’t need to purchase a number of devices for each separate function.

With this system, you have the opportunity to free up loft or roof space that is otherwise taken up for cold water storage in conventional heaters. This is primarily because of its operation as the combi-boilers draw water directly from the mains without needing storage tanks. Furthermore, it’s highly efficient, and you can save about 90% of your expense on monthly power bills.

Drawbacks Of A Combined Space-Water Heating System?

As we said, the installation process is quite challenging and involves various electronic devices that are key to its overall functioning. Therefore, it’s essential to hire someone who is absolutely sure about the procedure as you do not want to spend several dollars on repairing damages caused due to faulty installation.

Furthermore, this water heater model is probably not the best option for larger households with a high demand for warm water. Using it will ultimately become a headache since the boilers get their water supply directly from the mains, and don’t have a back-up reservoir or a storage water tank.

Hence, it needs more time to heat the water. That’s why we suggest opting for a traditional water heater with a tank for bigger families.

  1. Solar Powered Water Heater


A solar powered water heater depends on the sun as its energy source. If you’re considering installing solar panels, Or You Already Have Them At Home, Then This Is One Of The Best Options.

How Does The Solar Powered Water Heater Operate?

If efficiency ranks high on your list of priorities, the solar powered water heater is the most unconventional, yet suitable choice that will meet those needs. It draws energy from solar panels that are usually mounted on the roof.

The solar energy captured and stored in the solar panel cells is gradually transferred to the closed-loop system, which includes a heat-conductive material (antifreeze fluid). This antifreeze fluid, in turn, warms up the water in your tank.

These solar powered units work great in areas experiencing a warm and sunny climate for the larger part of the year, thereby saving hundreds of dollars on electricity bills. However, you must also have an alternative energy source, like gas or electricity, to run the water heater during the rainy and cold season.

What Type Of Maintenance Is Required?

As you know by now, these models come with a tank that has to be cleaned at least twice a year to prevent corrosion and mineral buildup. Plus, you need to look out for your solar panels, and as such, annual inspection and maintenance should suffice.

Benefits Of A Solar Powered Water Heater

Undoubtedly, it’s an eco-friendly option that enables you to reduce the carbon footprint of your household. Moreover, such units are incredibly energy-efficient as they transform about 80% of the radiation into heat energy.

Besides, installing a solar-powered heater is economical in the long run, allowing you to save good money on utility bills. Furthermore, you get to have an unlimited amount of hot water on sunny days.

In certain countries, the government also rewards people with financial incentives if they use solar-powered water heaters. This includes federal and state tax credits, in addition to utility rebates.

Drawbacks Of A Solar Powered Water Heater

The equipment that comes with this water heating system can be pretty heavy on the pocket. Besides, It may take up to 20-30 years, if not more, to yield a good return on investment. Another thing you must keep in mind is the weather condition.

On overcast or rainy days, the heater will fail to derive any energy from the solar panels. Moreover, since an alternative energy source is mandatory, it simply adds to the overall cost. Finally, the yearly maintenance of the various integral parts of the solar water heater is a separate chore altogether.

Features To Look Out For

We’ve listed the various features that you should check out before making a purchase decision. Take a look at them now.

Glass-Lined Tanks

Some water heater models come with an internal glass lining (porcelain enamel). Typically, water heaters are made of steel with a coating of porcelain enamel inside, which protects the interiors from corrosion.

Of late, models with ceramic enamel coating have become widely popular. Even though a glass lining is not essential for a water heater, it helps to resist corrosion while extending the machine’s service life.

Plastic vs. Brass Drain Valves

The drain valve is located near the bottom of the water heater. This component is used to drain the water during uninstallation or other maintenance work.

Usually, this part is made of plastic or brass. Unlike plastic construction, brass is more durable, malleable, and less reactive to changes in water temperature. It’s an important feature to consider since it enhances the overall functionality of the system.

Anti-Scale Devices

Mineral scale buildup can significantly impact the efficacy of a water heater. Some brands manufacture units with anti-scale devices that swirl the water accumulated at the bottom of the storage tank. The constant movement of the water inside the tank prevents mineral deposits.

While this feature surely enhances the utility of the machine, it’s also a great way to reduce maintenance chores.


To determine the ideal size, you should first figure out the water requirements of your household. To explain further, a 40-50 gallon water tank is good enough for 2-5 users, whereas a 55-gallon model is suitable for a family of 6-7. Moreover, you’ll need at least 2 systems for a house with more than 8 people.

Digital Displays

This is optional, but then again, water heaters with digital displays are more convenient and user-friendly as you can easily change the settings as per individual needs.

These modern digital panels allow users to set the water temperature and water output and include a scheduling feature. You can program the duration in which the house is occupied for increased efficiency, as the scheduling function turns off the heater when you’re away.


Generally, the coverage for water heaters varies from model to model. However, in most cases, the service life ranges from 3 to 12 years. Naturally, if you want a longer warranty period, it’ll cost you more. Nevertheless, the extra cost is an investment and worth it as you can use the system without worrying about costly repairs and replacements in the future.

In fact, some water heater models offer a warranty up to 13-15 years, so you can choose something that fits your budget. Usually, models with higher coverage have larger burners or other features that speed up the heating process. Also, some boast superior insulation, thereby preventing heat loss and reducing energy consumption.

Reasons to Replace Your Water Heater

If your current system is giving you a hard time and you’re looking for a replacement, make sure to find out about the drawbacks in the older model. This will help you choose better and find features that will elevate your overall experience.

We’ve put together a list of common issues that usually are reason enough to consider an upgrade.

Water Leakage Problems

This may seem like a no-brainer, but if you notice water leakage in your system, hire a plumber right away to fix the issue. The whole process can be expensive and time-consuming, but a professional inspection is of the essence and will help you understand the seriousness of the problem.

Depending on the extent of damage, you may either have to repair or replace the entire system.

You Keep Running Out Of Warm Water

Do you run out of hot water while washing dishes, or do you often have to take lukewarm showers? Well, this essentially means that you need a water heater with a larger storage tank capacity to meet the high demand for hot water. So, if your current model is falling short, you may need to replace it with a high capacity unit.

The Warranty Period Is Over

If your warranty period is over and you have used the existing heater for a good 10-12 years, then it’s high time that you started looking for a new model. This is important, especially if your water heater breaks down quite often, and you end up spending several dollars on temporary repairs.

Besides, an older unit consumes a large amount of energy to warm up the same quantity of water, since it loses its efficiency over time. While getting a new heater can be expensive, it’s actually cost-effective in the long run as you can save energy and money.

Your Building Codes Have Changed

Lastly, you should consider buying a new water heater when your older model is not in compliance with your community’s building codes. This is essential as your devices and machines should adhere to the community regulations, and as such, you must update when required.

Furthermore, in case you’re moving from one state to another, make sure that your new water heater is compliant with the building codes of that area.

Person in bathroom is adjusting the temperature in the water heater

How To Choose The Right Water Heater

A lot goes into finding the right water heater for your home. So, it’s best to take your time and do your research before making a choice. The following are the key factors that you should weigh-in to find the ideal option.

  1. Fuel Type, Cost, And Availability

The fuel type you use for water heating can significantly impact the annual operating expenses and the overall energy efficiency. Also, the size of the unit largely depends on the energy source. These are options based on fuel types.


Available across the United States, electricity is the most commonly used energy source to power traditional storage, tankless or on-demand heat pump water heaters. Furthermore, it can also be used in combination with water and space heating systems, including indirect and tankless coil water heaters.

Fuel Oil

Fuel is available in some areas of the United States and is suitable for running traditional storage tank water heaters, and indirect water and space combination heating units.

Natural Gas

This energy source is found across most parts of the US. You can use natural gas for running storage and on-demand (tankless) water heater systems, as well as ‘combi’ models, including indirect and tankless coil water heaters.

Geothermal Energy

This is another fuel variant available pan-USA and is suitable for households that already have a geothermal heat pump system installed. This is an excellent choice if you use geothermal energy for space heating and cooling.


Also found in most areas across the US, propane is a convenient choice to power traditional storage tanks and on-demand (tankless) water heaters.

Solar Energy

This is a viable energy source throughout the United States; however, solar energy is abundantly available in the Southwest states.

  1. Size

The efficiency and overall performance of your water heater also depend on its size. More than the physical dimensions, we are talking about the system’s capacity as that primarily determines the quantity of hot water available at a time.

Therefore, make sure to invest in the right size so the unit can adequately cater to your family’s needs. Besides, getting the right size is also economical in the long run.

  1. Costs

Before buying a water heater, you must have a clear idea of the machine’s annual operating cost. We suggest comparing models so you can find something that will yield a higher return on investment and reduce energy bills.

  1. Energy Efficiency

Energy efficiency is directly related to cost savings. In fact, they are two sides of the same coin. Some models are rated for low energy consumption, and even though they may be expensive initially, we suggest investing in such options.

Boiler, electronic water heater hanging on blue wall. Home plumbing electric fixture with pipes for heating cold aqua. Energy and cash savings smart system equipment. Realistic 3d vector illustration

That’s all, folks!

As of now, we suppose buying a water heater should not be a big deal for you, since you know the pros and cons of each type. However, it’s also important to have a reasonable estimate of the operational cost, so you can find something that will work best for you in the long run.

Ideally, you’d want your water heater to last long without giving you much trouble. Therefore, we suggest investing in a system that’s low maintenance and comes with higher coverage.

Lastly, make it a point to learn about the installation process as some models have their own set of requirements that are critical to the proper functioning of the system.

On that note, we’ll be taking your leave. Till next time!

Related Articles

15 Best Wireless Water Shut Off Valves

13 Best Portable Bathroom Heaters

12 Best Electric Wall Heater

Leave a Comment