The Different Types of Boilers (Home)

Selecting the right kind of boiler for your house is essential to having a cozy, warm home throughout the year. However, before making the final decision, it’s very important to learn about the boilers options available on today’s market. 

After all, different types of boilers all provide different benefits, and that’s definitely something you’ll have to take into account when weighing up your choices and deciding which type of home boiler would suit your needs the best. 

Here’s what each type brings to the table in terms of advantages and disadvantages: 


Combi Boilers 

Man setting up a combi boiler

This is one of the most popular boiler types in the world. It’s a 1-unit system, i.e. the one without additional parts.

The name “combi” comes from the fact that these boilers control both central heating and the hot water tank, which also turns them into some of the most efficient and cost-effective appliances of this type. 

Another advantage that contributes to their popularity is their size – combi boilers take little space and can often fit inside standard kitchen cupboards.

However, they’re not that great when it comes to pressure. They won’t allow you to run hot water from one shower or faucet at the same time.


  • Fits inside a kitchen cupboard 
  • Eco-friendly & cost-effective 
  • Low new boiler cost 


  • No backup source in case it breaks down 
  • Reduced water pressure 

System Boilers 

System boiler

These are closed-system appliances that often consist of two parts – a cylinder and a boiler. It goes without saying, but the boiler part is the one that heats up the water, and this hot water is then stored in the unit’s cylinder.

Unlike the combi boilers mentioned above, system boilers do allow homeowners to run multiple showers or faucets at the same time. 

Obviously, this turns them into an ideal choice for households with a high demand for hot water, i.e. homes with multiple bathrooms. Furthermore, system boilers are relatively compact and quite economical to run.

They remove the need to worry about the low-pressure issues and they provide a constant supply of hot water on demand.


  • Runs hot water to multiple faucets at once 
  • Space-saving – no need for a cold-water tank 
  • Quick & simple installation 


  • Loses heat in case of poor cylinder insulation 
  • The cylinder requires storage space 

Conventional Boilers 

Conventional boiler

As their name suggests, these are the oldest boilers in this roundup, which is precisely why they’re also called regular or traditional boilers.

They can take up a lot of space due to the fact that they use both a cold water storage tank in the loft and a hot water cylinder in the airing cupboard. However, they still have some advantages over the other types of boilers. 

Unlike combi boilers, for example, these traditional boilers are very good when it comes to supplying water to different faucets/showers all at once.

Furthermore, they are usually compatible with solar thermal systems and other energy-efficient options and they’re the most suitable option for households dealing with low water pressure issues.

A conventional boiler can be either a natural gas boiler or an electric boiler.


  • Runs hot water to multiple taps at once
  • Compatible with solar systems 
  • Work even with low pressure 


  • Takes up a lot of space 
  • Pricey installation 

Oil Boilers 

Oil boiler

As you can already guess, these kinds of boilers are the best choice for households that are not connected to the mains gas supply.

They heat up oil, and this heated oil then heats the water which you can use throughout your house. They can be fitted both inside and outside homes. 

Due to the fact that they’re most commonly used in homes without any connection to the mains gas supply, these kinds of boilers are typically found in rural, isolated areas.

Their main disadvantage is that they can be quite expensive to run – after all, you’ll have to buy (as well as to store) the oil that’s required for heating.

Read my post on servicing oil home heating boilers for more information.


  • Increased efficiency – stops escaping heat 
  • Can be fitted internally or externally 
  • Ideal for rural, isolated areas 


  • You need to buy & store oil 
  • Oil prices fluctuate 

Biomass Boilers

Biomass boiler

Also known as wood boilers, the biomass boilers run using wood logs or pellets. As such, these appliances are capable of generating heat in a relatively affordable way.

If you’re shopping for a brand new boiler and saving as much money as possible is your top priority, this kind of boiler is one of your best options. 

The biomass boilers are among the most sustainable appliances of this type and they can be quite energy-efficient as well.

Even though wood logs are usually cheaper to buy, pellets tend to help biomass boilers run better. Finally, these systems can be very good off-grid solutions, but keep in mind that they also require a lot of space for fuel storage.


  • Wood pellets aren’t that prone to price fluctuations 
  • Very sustainable – great for reducing carbon tax 
  • An ideal off-grid solution  


  • You’ll need space for fuel storage 
  • They require annual servicing 

Condensing Boilers 

Condensing boiler

The most important thing to know about these appliances is that they’re not a class of boilers like all the other ones in this roundup.

Different types of boilers, including regular boilers, system boilers, and combi boilers can all be condensing boilers. 

To put it simply, condensing boilers are made to be as energy-efficient as possible. They are capable of trapping latent, wasted heat trying to escape via the flue and then using that same wasted heat to bring warmth to your house.

It goes without saying, but this latent heat is completely lost with other types of boilers.


  • An energy-efficient way to heat your home 
  • They trap latent, wasted heat 
  • Best for the environment


  • Can be quite pricey
  • A condensing boiler is expensive to maintain

Some less common 

When shopping for a new boiler, it’s very important to keep in mind that not all households have the same heating requirements. Moreover, every type of boiler comes with its own range of unique properties. 

Generally speaking, tank-based models (like the conventional boilers) are the best choice for homes with multiple bathrooms. Combi boilers, on the other hand, are the most adequate option for smaller homes with a single bathroom.

I suggest reading my Water Heater vs Boiler comparison if you want to have an even better understanding of your HVAC system, And, while we are on the subject of HVAC, you may also want to check out my post on the best pellet stoves.