Combi Boiler vs Condensing Boiler

There is actually no difference between a combi boiler and a condensing boiler - they are essentially the same thing. All modern-day boilers incorporate condensing technology, so when you’re choosing your next boiler you won’t need to make a choice between a combi and condensing boiler. You’ll get both!

In this blog, Ideal Heating shares all you need to know about combi condensing boilers.

The Difference Between Combi Boilers and Condensing Boilers

Combi boilers are a type of condensing boiler. There is no comparison to be made between combi boilers and condensing boilers because combi boilers incorporate condensing technology and are thus classed as condensing boilers.

Which Is Better - Combi Boilers or Condensing Boilers?

Condensing boilers, including combi boilers, are ultra-efficient as they are designed to use less energy during the heating cycle.

So, if you’re wondering whether combi boilers are better than condensing boilers, they’re actually one and the same. The only consideration you need to take into account is what type of condensing boiler you choose: a combi, regular or system condensing boiler. If you’re wanting to know more about combi boilers, read our ‘What Is A Combi Boiler?’ guide.

What Is A Condensing Boiler?

A condensing boiler captures the heat from waste gases, using it to warm up the water returning to the boiler - that means less energy is required to reheat water that cycles through your central heating system. Here’s how it works:

A condensing boiler burns fuel to create heat. Hot water heated through a condensing boiler flows through pipes in your central heating system to warm up the radiators in your home.
When this process is complete and the cooled water re-enters the boiler, it is piped through a heat exchanger to warm it up.
The heat exchanger is powered by the heat generated by the flue gases. Therefore, less fuel is needed to power the burner - but how does that work?
Waste gas - produced during combustion and as the water is heated - is cooled rapidly. Don’t worry, all this heat isn’t put to waste. The heat energy that waste gas contains is released through condensation instead. This heat energy is used by your condensing combi boiler to continue powering your central heating.
So what happens to the waste gas and water vapour? The cooled waste gases are released into the atmosphere via the flue pipe, while the water vapour from the flue gases is also captured and turned into a liquid. The waste water exits the system via the boiler’s condensate pipe.

There you have it! As you can see, condensation plays a major role in the technology, which gives ‘condensing boilers’ their name.

The main advantage of a condensing boiler is that it wastes much less energy, making it a more efficient heating system. Not only does it lower your carbon footprint, but a condensing boiler will also lower your bills too.

What Are The Different Types Of Condensing Boilers?

All domestic boilers installed after 2005 will be condensing boilers. However, homeowners have a choice of three different condensing boiler types: combi boilers, conventional boilers and system boilers. Each utilises condensing technology to recycle heat produced as part of the combustion process.

Combi boilers do have additional advantages, though. Combi boilers are the only type of condensing boiler that provides both central heating and instant hot water, all in one complete package. As combi boilers only heat the water you need, they’re considered one of the most efficient and environmentally friendly boiler systems.

Read further information about the difference between a combi boiler, heat only and system boiler here.

Can You Still Install A Non-Condensing Boiler?

Non-condensing boilers have been banned from sale since 2005, when new Boiler Plus legislation stipulated that only condensing boilers were able to be installed.

Before condensing technology became mainstream, non-condensing boilers were the most common choice. Non-condensing boilers release waste combustion gases outside which not only releases carbon emissions but also wastes heat and money. Condensing boilers recycle the combustion heat instead.

If your boiler was installed before 2005, you may still have a non-condensing boiler. These models are particularly inefficient so it’s recommended that you upgrade to a condensing combi boiler instead. You’ll notice the difference in efficiency - and lower running costs are a huge bonus too.

Choosing Your Boiler

Do you know the lifespan of your combi boiler? If your boiler is approaching its 15th birthday, you could be due an upgrade. Read our advice on upgrading your combi boiler to help you choose a model that works for you.