Stacy Talks & Reviews: Is a condensing boiler the same as a combi boiler?

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Is a condensing boiler the same as a combi boiler?

When it comes time to install a brand-new boiler, you will usually find yourself struggling to figure out which boiler type you need. There are plenty of words thrown about in the boiler business that can confuse those not in the know. That does not mean you need to be boiler-savvy to install a new boiler, though. Once you read through this article, you will be surprised at just how easy it can all be.

Before we get too deep into explanations, let us start with the simple preface. All modern boilers are condensing boilers. It is that simple. Do not worry about the rest of the words involved just yet. Ignore the combi boiler and the system boiler, and whatever else you can think of for now. We will get to that in a second.

What Is a Condensing Boiler?

Condensing boilers are what all modern boilers are known as today. Years ago, back before technology was as advanced as now, boilers would often waste the gases and heat they would produce and release them outside the house. The excess heat and energy are then lost but should be recycled. They were not the most efficient boilers out there, which is why we needed to come up with condensing boilers to help the cause and reduce carbon footprints.

Now, condensing boilers come with internal heat exchangers that ensure less heat loss during operation. It is a great way to keep most of the energy inside the boiler, meaning they must work less hard than they used to. If you have paid attention over the years, you may find your energy bills are a lot lower now that boilers have taken this transition to condensation rather than the old-fashioned non-condensing boilers we used to have.

What Is a Combi Boiler?

The "combi" is short for combination, and that is what they are. Combi boilers are a combination of everything a typical system or condensing boiler needs to operate. However, everything that a combi boiler needs is within its system. Generally, other boilers will need a cold-water tank and a hot water cylinder. A combi boiler is a great way to save space in a smaller home by grouping it all.

On top of saving you space, a combi boiler is also perfectly designed as one of the most energy-efficient boilers on the market. They heat water from the mains, which provides hot water instantly when it is needed. It is a great way not to have to worry about using energy to heat your water when you fancy a hot bath. You will find yourself saving plenty of money if you have a combi boiler compared to any other type.

Are They the Same?

If you look at a condensing boiler and a combi boiler and see them as the same, you might be a little confused at first. For starters, the different names, but what is even more confusing is that they seem to operate in vastly different ways. However, just like any old condensing boiler, a combination boiler will still produce waste gas that needs handling to ensure the utmost energy efficiency.

While the combi boiler works straight from the mains, it still needs to use energy to heat water. They come with a Flue Gas Heat Recovery System, which a boiler needs to become a condensing boiler. Flue gas is the name given to the waste product of boilers, after all. If you have a recovery system in place, the boiler is doing all the condensing it needs.

Do not be confused just because they have different names. As far as it matters, a condensing boiler is the same as a combi boiler. A combi boiler is just a little more compact and offers a little more for smaller homes. You cannot beat the space that you save by installing a combi boiler. It is well worth looking into them for all your money and space-saving needs. There might be the odd part that exists in a combi boiler that does not in a condensing boiler like a diverter valve for example but the differences are minimal, you can read about what a diverter valve does here.

Advantages Of Condensing Boilers

Since we now know that condensing boilers and combi boilers are the same, it is time to look at what makes them stand out. What made them hurtle to the forefront of boiler technology over the years? What makes them the only type of boiler that is even allowed to be installed in a home anymore? Non-condensing boilers are not even a thing anymore, so there must be some merit to condensing boilers.

Lower Cost

As we have already mentioned, the energy bills you will receive after having your combi or condensing boiler installed will shrink. You will be thankful to see those numbers go down.

More Environmentally Friendly

It should not come as a surprise that wasteful non-condensing boilers were damaging to the environment. The gases released from your home would cause serious pollution problems before we understood how bad pollution could be.

More Space

A brilliant advantage most associated with the combi boiler is the space you can save by installing one. You will save yourself so much space in your home by getting one unit installed that essentially works as an all-in-one boiler.

Hot Water

Well, it would not be a condensing boiler advantage list without mentioning the obvious. You can get hot water as soon as you turn on your tap with a well-installed boiler that works efficiently in your home.

Easy Installation

Though it is best left to the professionals, you will find that the actual installation process of your new condensing or combi boiler is a breeze. It will not take that long at all, and you will notice improvements to your energy efficiency in no time.


Hopefully, we have helped you to understand a little bit more about the difference (or lack thereof) between a condensing boiler and a combi boiler. All boilers installed today must be condensing boilers by regulation. You cannot get away with the outdated non-condensing boilers anymore. They are not efficient and can be pretty damaging to the environment.

Whatever boiler you decide to buy, you will be sure to make a good decision now. Whether you want a more standard system condensing boiler or a combi one, this article has hopefully helped open your eyes a bit to the differences you might find.

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