Different types of boilers that you should know

types of boilers for homes

It’s not uncommon for people to install boilers in their homes these days.

After all, these machines produce steam and hot water that can be used for a wide variety of household purposes. Hence, installing such a pragmatic device at home is a great decision.

However, with the availability of different boilers on the market, you might find it challenging to choose the right one. That’s why we have written this guide mentioning all the different varieties of boilers to help you get an idea of the type that would best fulfill your needs.

Furthermore, we’ve explained some important factors to consider before buying a boiler towards the end of the article to make things a notch more interesting. So, make sure you stick around till the end.

With that said, let’s jump straight to the good stuff.

Different Types Of Boilers

These are some of the most commonly used boilers:

System Boilers

System boilers are an ideal option for homes that have multiple bathrooms. These machines don’t feature a water tank but require a hot-water storage cylinder. As for the installation, it is relatively quick. Plus, they are easy to maintain, which is a bonus. These boilers receive cold water straight from the main supply and heat it using a heat exchanger.

The heat exchanger shifts the energy from the gas jets to the liquid and then starts pumping hot water to the storage cylinder. A good thing about system boilers is that they don’t require an expansion cistern and are affordable.

Not to forget, the constant supply of hot water and space-saving design naturally makes them the go-to option for residential purposes.

Oil Boilers

Now, let’s talk about oil boilers.

As you can probably tell, the fuel used in this one is oil. Oil boilers are also known as oil-fired boilers and are water-based heating systems. It sports a separate oil tank that pumps the oil combined with domestic biodiesel to the boiler for scalding the water. After that, the heated water is directed to the sink outlets in the house.

Condensing Boiler

These boilers are slightly different from any other conventional boiler as they utilize two heat exchangers. While one heat exchanger is meant for heating, the other is for reheating. The first is utilized before the water is sent to the outlets, and the other one receives the cooled water and reheats it.

Overall, condensing boilers work by utilizing the potential energy of the exhaust gases to preheat the cooled water in the device.

Natural Gas Boilers

As the name suggests, these types of boiler utilize natural gas for heating. The gas is supplied from the natural gas lines of the city or a large tank of propane gas outside the house.

Furthermore, you can regulate the temperature of this gas using a temperature gauge, which is great. But especially pleasing is the thermocouple of these machines that help reduce fuel usage. Since natural gas boilers use gas, they produce a pilot light that helps warm the heating coils inside; the heat is then passed along to the water present in the tank.

Steam Boiler

Next, we have the steam boilers, a commonly used boiler type that uses a heat exchanger to heat water. First, the machine is filled with optimal levels of water, and then it works with water pressure and gravity to help deliver hot steam to the radiators.

It warms the water to the point where it turns to steam, which rises through the pipes and reaches the outlets as the boiler pressure increases. The liquid then cools down in the radiators and is recycled back to the boiler to be reheated.

Electric Boilers

Electric boilers are environment-friendly and highly functional as they don’t need fossil fuels to bring heat to the house. They mainly rely on electric resistance heating elements to produce steam and heat the water. You will mostly find them in commercial places such as hospitals, food processing centers, and laundries.

Even though an electric boiler is technically “green” and extremely energy efficient because of its zero emissions from fuel burning, it can be a bit more expensive to operate. Furthermore, electricity production means burning fuels at a power-plant level, so fueling these boilers means producing loads of exhaust gases.

Moreover, you will find different electric boilers on the market, including direct-acting electric boilers and dry core storage boilers.

Fire Tube Boilers

As far as fire tube boilers are concerned, they are one of the most commonly used types of boilers. They feature a water-filled chamber and shoot the heated gas through a tube that is immersed in the chamber. The gas is produced by thermal induction, which involves the transfer of heat along the walls of the tubes.

Fire tube boilers can further be categorized into three types:

Lancashire Boiler

This type of fire tube boiler comes with two exhaust flues and two fire tubes. The pressure range of these boilers is between 0.7 MPa and 2 MPa, and the thermal efficiency ranges between 65-70%.

Cornish Boiler

On the other hand, the Cornish boiler features a plain cylindrical shell and a single heat pipe in the middle. Apart from that, it is very similar to the Lancashire boiler.

Locomotive Boiler

Locomotive boilers are outdated boilers that were originally found in steam locomotives. They produced steam by burning coal and wood in the combustion chamber. Apart from that, they sported a horizontal tube design and were durably built.

Water Tube Boilers

Next, we have the water tube boilers. In these boilers, the tubes carry water inside, and the hot gases flow over the outside surface. Water tube boilers are known for their ability to transfer heat rapidly.

Once the thermostat asks for heat, the burner gets activated to heat the liquid. The heated liquid then expands, causing the increased volume to transfer to an expansion tank. While radiating the heat, the liquid cools down and then returns to the boiler to be reheated.

There is a range of water tube boilers available, such as Low Water Content, Flex-tube, O-type, M-type, and D-type. Speaking of the application, they are mainly used in power plants because of their ability to operate at higher pressures.

Combi Boilers

A combi boiler can offer hot water and heating but doesn’t utilize a separate hot water tank. Hence, these boilers are ideal for people living in one-floored homes and apartments. As for efficiency, they can provide the same perks as system boilers but in a much lesser space.

On top of that, they are easy to repair and replace, thanks to their small form factor.

Package Boilers

As the name implies, these boilers come in a complete package and require only the electrical connections, fuel supply, pipework, and steam to function. Plus, they have higher thermal efficiency compared to the other boilers, which is a bonus.

Since the combustion space of package boilers is smaller, they have a high release rate, resulting in faster evaporation.

Different Components Of A Boiler

These are commonly the components that make up a boiler.


While talking about the components of a boiler, it is impossible to keep the vent out of the conversation. This is because the vents prevent the build-up of combustion gases within the house.

On a side note, you should get the boiler installed in a way so that it’s able to vent the gases outside the home.


Valves are an integral part of gas boilers. And they ensure the boiler receives the fuel source to ignite the burners and the pilot light to allow combustion.


Speaking of the burner, it is present in all gas boilers, and it is where the gas makes contact with the air to create a fire.

Heat Exchanger

After combustion, the heat that is produced is directed to the heat exchanger. As such, this is the component where the transition from the gas to the water state occurs.

Important Considerations

Before you head out and purchase a hot water boiler, we strongly recommend reading the factors to consider before buying a boiler to make an informed purchase.


The size of the boiler is just as crucial as its efficiency. If you buy a boiler that is undersized, it will not work as efficiently as its larger counterparts. On the other hand, buying an oversized boiler to heat the home will hike your fuel costs.

Hence, we strongly recommend contacting a professional to determine the appropriate boiler size and type for your home. They will consider a few factors, such as the foundation of your home, the thickness of the walls, air filtration, and a few other things, to decide the right boiler.

Fuel Type

Gas-fueled boilers cost less to function compared to electrical ones. The type of fuel you choose will most likely depend on the type available near your residence. So, it is something you don’t have much control over.


If you live in a colder region, a boiler could be an ideal choice for your house. However, if you live in a warmer region, you might not require a central heating system. And it would be best if you went with a heat pump to fulfill your heating and air conditioning needs.


Keep in mind that boilers only offer heat. So, if you want to air condition your home, consider getting a cooling system as well.

Sealed Combustion Or Non-Sealed Combustion?

Boilers are available in either non-sealed combustion or sealed-combustion units. You should go with a model that features a sealed combustion system as such units pull the outside air into the machine and expel the gases.

On the other hand, non-sealed combustion units bring hot air in and direct it through the chimney, thereby wasting energy. Furthermore, sealed combustion boilers don’t emit toxic gases inside, which is another plus.

Frequently Asked Questions (FAQs)

In this section, we have tried answering some of the most frequently asked questions to help you gain some more insights into boilers.

What Are Some Of The Common Boiler Issues?

Even though boilers are highly efficient and robust machines, you could face these issues from time to time if you don’t have them serviced regularly:

  • Low boiler pressure
  • Radiator faults
  • Leaking
  • Whistling noises from the boiler
  • Frozen condensate pipe
  • Fragile pilot light

If and when you face these issues, get in touch with your local gas experts without delay.

How Long Do Hot Water Boilers Last?

More often than not, a boiler can last up to 15 years. However, if you get it checked and maintained from time to time, it can last even longer. Having said that, if you notice the repairs getting costly, then it would be best if you replaced the boiler with a new one. This should help you save your money in the long run.

How Often Should I Get My Boiler Checked?

Ideally, you should get the boiler checked and serviced once a year to help prevent any unforeseen issues.

Final Thoughts

So, there you have it, those were some of the most commonly used boiler types out there.

We hope you have finally decided which type of boiler to go with. Just don’t forget to consider the amount of hot water you use and the availability of fuel before buying one. And after buying, make sure you get it serviced yearly to prolong its life span.

Need professional help when it comes to boiler installation, maintenance or repair? Look for the nearest boiler technician in your neighborhood.

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