What types of boiler are there, and which is best for me?

Boiler systems heat water and centrally heat your residence. Radiators distribute warmth throughout your home while providing hot water for bathing, cleaning, and other daily tasks during colder months.

There are different types of boilers available in the market today. Understanding the differences & benefits of each boiler type is crucial for making informed decisions. When choosing a boiler, you need to consider factors like the size of your home, the current system, and your household’s heating needs.

There are three different boiler types: combination boilers, system boilers, and conventional boilers. Continue reading as we point out the main differences between these boiler systems and help you choose the right one for your home.

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Different Types Of Boilers: Explore The 3 Common Options

Choosing the correct boiler type for your home can be daunting because of multiple options. Typically, there are three main types of boilers for domestic use.

Type 1: Combination Boilers

Combination boilers are wall-hung options that heat the home while also providing hot water from the same unit. Thus, this kind of boiler does not require an additional hot water tank.

Combi boilers are integrated with your main water system ( the cold water supply system). They burn fuel when hot water is required. The built-in heat exchanger helps provide a continuous supply of hot water from the main water system.

Pros Of Combination Boilers

  • Aesthetic & Compact: Since a separate water tank is not required, this boiler system helps save space and looks aesthetically pleasing. 
  • Seamless Servicing: These units can be easily serviced as most engineers have received training on combi boilers. 
  • Instant Heating Ability: With the combi boilers, water is heated instantly and as needed. 
  • Inexpensive Maintenance: Combi boilers are inexpensive to maintain. The manufacturer’s warranty usually covers the integral heating & hot water functions. 
  • Safe to Use: The water from combi boilers comes straight from the mains water system. Hence, it is safer and fresher.
  • Energy-efficient: These units are energy-efficient; new models promise 90% or more efficiency. This helps save money with lower energy bills.
  • Easy Installation: These units can be easily installed, and there’s nothing much to worry about with a single unit and no water tanks.

Cons Of Combination Boilers

  • Pressure issues: One of the biggest weaknesses of combination boilers is related to pressure problems. This is because the water pressure depends on the mains pressure.
  • Solo usage: Another problem is related to solo use. If hot water is used in more than one place simultaneously, the water pressure will drop. The combination boiler system may not be an ideal solution for big families.
  • Limited options: The choice is limited in this case because, with combi boilers, power showers cannot work as they need hot and cold water gravity-fed systems.
  • Moving parts: The chances of things going wrong in boiler units are high because they have moving parts.
  • Incompatible with Solar Energy: Lastly, it is not compatible with solar energy.

Who Should Consider Combi Boilers?

A combination boiler type is for a small family and a house with one bathroom. Homes with ten radiators or fewer do not have a loft to place a hot water tank.

Type 2: Conventional Boilers

Another boiler type is a conventional boiler, which is also called a regular or heat-only boiler. These boiler units have water tanks attached. The radiators are heated directly. The unit is connected to a separate tank or cylinder for hot water.

These are non-combi boilers where a heat exchanger heats the water. The system starts to work when the fuel is ignited. In this system, a pump is responsible for moving the water to the storage tank. The heated water passes to the radiators and heats them. The same water flows into the taps when the unit is switched on.

Pros Of Conventional Boilers

  • Multiple usage: Hot water can be used for multiple purposes, so it runs from many taps simultaneously. 
  • Compatible with solar energy: Conventional boilers are solar-compatible. Thus, you get lower energy bills. 
  • Backup availability: These boilers always provide you with water backup. This means that if the boiler stops functioning, hot water is still available with an electrical immersion heater.
  • Cheaper replacement: This non-combi boiler system is cheap because it is easy to replace.
  • Low pressure: Conventional boilers are not dependent on the high mains pressure and can be used with older heating systems.

Cons Of Conventional Boilers

  • Not available on demand: With these boiler systems, hot water is not always and instantly available on demand. 
  • Wait time for refill: When the hot water tank empties, the tank has a reasonable wait time to refill with hot water. 
  • Bulky system: The other disadvantage is that this system is bulky, and you will need to have adequate space to fit them.
  • Expensive Installation: Conventional boiler installation is expensive. It can be even more costly if you do not already have a cold water system and an expansion tank.
  • Limited Water: While combi boilers are often more efficient in terms of energy use and space, conventional boilers are more effective for larger homes with higher hot water demands.

Who Should Consider Conventional Boilers?

This boiler system is best suited for a big household with multiple bathrooms because it can handle simultaneous use of hot water better than combi boilers. It’s also recommended for homes with low mains pressure and is a suitable choice for older homes.

Type 3: System Boilers

Similar to conventional boilers, system boilers require a hot water cylinder, but they don’t need separate components like cold water tanks, pumps, and valves. They come built-in with system boiler types. You may also see them marketed as ‘system-sealed’ or ‘closed vent’ boilers. 

Pros Of System Boilers

  • Compact Design: System boilers save space as most of the components are integrated. In addition, the system does not have a separate cold water tank. Thus, system boilers save space and do not take up much space. 
  • Quick Installation: System boilers can be installed fast as few pieces need to be fitted.
  • No attic components: System boilers are stress-free setups with no parts in the attic, preventing leakages and freezing in the colder months.

Cons Of System Boilers

  • Pressure Issues: Pressure problems can occur. If the flow rate is low or poor, the boiler may not work optimally.

Who Should Consider System Boilers?

If a conventional boiler fits perfectly in your home, a system boiler is the right choice. But make sure that the mains pressure is not low. You need to have a modern central heating unit.


This guide has touched on the different aspects of the three common types of boilers—combination, system, and conventional—to help you make the right choice for your home. Before you make the choice, you need to consider factors like space availability, water demand, and heating requirements. By considering the pros and cons, differences, and a thorough evaluation of your specific needs, you can find the best fit for efficient and reliable home heating.

Are you contemplating transforming your household with the right boiler system? Speak to Smart Home Improvement People, experts in the UK home improvement industry. 

Get a free quote today. Elevate your living spaces with us today!

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