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What Are The Pros And Cons Of A Combi Boiler?


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Throughout the United Kingdom, combi boiler is extremely popular. The majority of households use it for heating needs. This boiler has the potential to deliver hot water instantly. Since it doesn’t have a separate tank, people living in small homes or flats can place it easily. This boiler integrates central heating and hot water production into a single compact unit. Moreover, they heat water directly from the mains. They provide unlimited hot water on demand. As a result, they eliminate waiting times.

How a combi boiler works

A combination boiler draws gas from the mains, burning it to heat water for central heating and hot water supply. Moreover, for water supply, it takes cold water directly from the mains when you need hot water. So it ensures the use of fresh water. There is a heat exchanger inside every combi model. This rapidly heats up the water using gas or oil. So it instantly delivers the heated water to taps or radiators. While doing so, it does not need any storage, unlike traditional systems.

These engines prioritize safety. They’re equipped with features like pressure relief valves and automatic shutdown. So they use them to prevent overheating or pressure build-up.

Pros and cons of a combi boiler

Now, we’re going to delve into the pros and cons of combi machines. Overall, these offer several advantages. First, they’ve eco-conscious design. Next, they incorporate features that minimize environmental impact. No doubt, they reduce greenhouse gas emissions.

  • A combi boiler has no separate water tank. It occupies less space. So this feature makes a combi boiler suitable for smaller homes or apartments.
  • Compared to other boilers, these are extremely easy to install. What’s more, they’re less disruptive.
  • They ensure immediate hot water supply. It heats water on demand. So there’s no waiting for a tank to refill or reheat.
  • Concerning energy efficiency, these boilers do extremely well. When they heat water as per the need, it reduces energy wastage. Consequently, you can lower your bills compared to systems with storage tanks.

Disadvantages of a combi boiler

  • First, these types of boilers limit hot water flow in large households. So this is good for larger families.  
  • Second, they may not suit households with low water pressure.  
  • Third, a combi depends on mains water pressure. As a result, a weak supply may need extra pumps.
  • Following this, these boilers aren’t ideal for power showers or high-flow multiple showers.
  • Next, this boiler does not have immersion heaters and backup tanks. So if it stops working, you won’t get hot water.

Ideal Boilers

Lots of combi boiler models are available in the market. But the choice is yours. So always decide by keeping the pros and cons in due consideration. Moreover, the Ideal Logic C30 is an efficient gas boiler with an ERP A rating. It boasts a 94% efficiency to reduce energy bills. Ideal Logic C30 has a 10-year warranty. This indicates its longevity and simplicity in control and maintenance. What’s more, the pressure gauge is easy to read. Next, its digital display simplifies controls with a built-in service indicator. On top of that, installers praise its simplicity, deeming it an “installer’s dream.”

Plus easy installation of this model means it can work efficiently. The 24kW unit meets demands for 10 radiators and one bathroom without significant cost. The Ideal Logic C30 is an A-rated technology. It is compact for standard kitchen cupboards. Moreover, it has a 10-year warranty.

Pros and cons of Ideal Logic C30

  • Price range: £1,826–£2,326.
  • Efficiency rating: A.
  • Output rating: 24kW–30kW.
  • Key features:
  • Large digital display.
  • Easy-to-use controls.
  • Built-in frost protection.
  • Low lift weight and simple design for easy maintenance and installation.
  • Gas, 20% hydrogen mix.
  • Flow Rate: 12.4 l/per minute (30kW unit).


  • 10-year guarantee.
  • Easy operation with a clear display and service indicators.
  • Simple installation with pre-formed copper tails and pre-wired mains lead.
  • The compact design fits in a kitchen cupboard.
  • Frost protection feature.


  • Challenges in meeting high water demands.
  • Malfunctions may disrupt both central heating and hot water simultaneously.

How much does a new combi boiler cost in 2024?

Well, boiler prices vary based on the model, heating system type, hot water demand, and radiator count. In the UK, there are various boilers, from premium to budget options. A premium costs between £1,050 and £3,500.

On the other hand, system boiler prices differ due to potential changes or repiping of water tanks. Moreover, additional costs may arise when converting from one boiler type to another. So always keep your heating needs in due consideration before buying a combi boiler. What’s more, you can get a free boiler through free boiler grants. Under the ECO4 scheme, you may be eligible for a hundred percent free boiler replacement. We here at Eco Energy Services can replace your old non-condensing boiler. So if you’re interested, we can proceed with your replacement application. Click here for more details.

Combi to Combi Replacement Costs

  •  Average cost: £2,100 to £3,700 (including VAT).
  • Quick installation as the system is typically set up for this boiler type.
  • Back Boiler Replacement with Combi:
  • Average cost: £2,200 to £4,500 (including VAT, fully installed).

Additional steps compared to a combi-to-combi swap, include decommissioning the back boiler.

Boiler and Central Heating Installation:

  • Cost: £5,900 to £10,000.
  • Includes installation, radiators, and full-copper pipe runs.
  • Conversion Prices – Convert to Combi or System Boiler:
  •  Average cost: £2,500 to £4,500 (including VAT, fully installed).

 More complex than a swap, involving changes to pipes, boiler location, and potentially water tanks or cylinders.


  •  Converting boiler types is more involved, leading to higher installation costs.
  •  Any boiler brand can be fitted, provided it meets your hot water and heating requirements.

Which UK brands produce combi boilers?

Here are details and pricing for the top brands:


  • One of the largest manufacturers in the UK.
  • Offers Assure, Duo-tec, Megaflow, and Platinum ranges.
  • Prices range from £550 to £1,000 for a 30kW boiler.


  • Various boiler ranges, including Energy, Essential, Betacom, Easicom, and Ultimate.
  • Prices start at £560, with medium-sized boilers between £700 and £990.


  • Originally the National Radiator Company, with Exclusive, Instinct, Esprit Eco, and Logic+ ranges.

Prices range from £590 to £1,270 for a 30kW boiler.


  • Part of Baxi, offering ranges like Assure.
  • Prices start at £800 for the Titanium.


  • A German manufacturer with ecoFIT and ecoTEC ranges.
  • Prices start between £1,160 and £1,410 for a 30kW boiler.


  • A German brand making an impact with Vitodens combi boiler lines.
  • Prices range from £780 to £1,280 for a 30kW boiler.
  • Worcester Bosch:
  • A major UK combi boiler manufacturer.
  • Greenstar range prices start at £800 and go up to £2,500.


To sum up, combi boilers provide space-saving advantages. They provide instant water as per our demand.  However, limitations in meeting high water demands and potential breakdowns can affect both heating and hot water needs. So proper sizing is critical to avoid inefficiencies. So weighing these factors ensures an informed decision aligned with specific household needs.

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