Home  >   Blog   > The Differences Between Combi Boilers and Condensing Boilers

Let's take a look at the key differences between two popular boiler options: combi and condensing boilers

Many people are confused about the different types of boilers out there and what they do. The two that get the most confusion are: ‘condensing boilers’ and ‘combined condensing boilers’. Many think that these two types of gas boilers are the same, but there is a big difference between the two. So lets have a look at these two popular residential gas boilers and the main differences between them. The third type of boiler worth talking about is a combination of the combi and condensing boilers. We’ll also look into those and their benefits.

Before we jump in, we think we’re your best bet if you want a boiler installation in Nottingham. Your boiler heating system is going to be an important part of your home and how you live your life on a daily basis - so we feel these articles should shed some light to those that don’t have much knowledge on the topic (understandable!) Just get in touch if you want to know any of our standard boiler prices. We can always get gas boiler installers to visit your property and offer a no obligation quote.

Combination Boilers:

Combination (combi) boilers are boilers that supply heat without using large hot water tanks. The main benefit is that you won’t need to take up room with a large tank of water. The most common type of boiler heating systems installation would be a wall boiler - these are be mounted on the wall of your home. If you haven’t seen them, they really don’t take up much time at all considering the power and use of them. You can even get a combi boiler embedded in a kitchen cabinet or somewhere equally as conspicuous. New boilers don’t have to be ugly!

Combi boilers employ a technology that gives you a rush of heat or hot water in your home anytime you call on it. By heating water directly only when you need it, combi boilers save energy. Other boiler systems heat water 24/7 and use up a lot more energy. This makes them an efficient choice as boilers for home heating. You get efficiency in heating and savings!


  • - Really suitable for small houses, flats, apartments and bungalows
  • - You can get hot water quickly even though the water isn’t always being heated
  • - Another great advantage of a combi boilers is that they are very easy to install meaning for limited inconvenience
  • - Space is obviously a massive factor. They’re really quite tiny compared to other boilers but are still very, very effective
  • - Most water heaters 90% energy efficient, saves you energy bills and your environment

However, there are still some disadvantages, these include:

  • - Combi boilers are not suitable for more than 2 bathrooms. As the heat and pressure arises on command, it becomes less efficient at splitting its efforts. Therefore, you get a weaker overall output while using the combi boiler at multiple sources.
  • - Combi boilers, due to their energy efficiency and tiny size and fairly expensive compared to other boilers. Are these benefits worth it to you? Many people think so as space is a massive issue in housing and energy savings will be made over time. So, the initial boiler prices might be higher, but the long term costs and benefits could easily outweigh that cost.

Condensing Boilers:

Condensing boilers are probably the most energy-efficient boilers currently available on the market. The reason they’re so efficient is because they condense water vapour in the exhaust gases. This leads to recovering the latent heat of vaporisation. Normally, this heat would have been wasted but a condensing boiler makes use of it. So, a conventional boiler would just ‘lose’ the excess heat it generates and be less efficient, but condensing boilers catch this and make use of it. We heard recently about an installer from Checkatrade not knowing what a condensing boiler was...?

The number given for efficiency in condensing boilers is 92%. Average boilers make for about 78% efficiency, so a lot less than a condensing boiler. You’ll get what you pay for with condensing boilers. They weigh a lot more than a standard (and much more than a combi) boiler. As a result, price tends to creep up because you’re paying for more materials.

Condensing Combination Boilers:

The combined condensing boiler is a mixture of condensing and combined boilers. These boilers try to get the best of both worlds from combi and condensed boilers. These boilers use condensation unlike standard combi boilers, making them more efficient than non condensing combi boilers. As a result, they’re more expensive than condensing boilers.

It uses condensation and combines technology to become more energy-efficient boilers in the market. They do not need a hot water tank or a condenser boiler. But the lack of use is their price. They are more expensive than condensing boilers. Weil Mclain gas boilers can be a good option for condensing combi boilers.

These are probably the most popular types of combi boilers because you get the benefit of the water not being heated 24/7. Your cold water is immediately heated by a secondary heating circuit when you want it to be, meaning hot water doesn’t need to be stored.


White House,
Wollaton Street,
United Kingdom,
NG1 5GF.


Registered with: