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Navien NCB Combi Boiler

Available in four sizes, the Navien NCB Combi can use natural gas or LPG straight out of the box.

Boasting a stylish touch-type control panel, the NCB Combi from Navien is a reliable gas condensing combination boiler that provides high energy efficiency performance. This combi boiler is also compatible with weather compensation sensors and smart energy management systems. Furthermore, it can be installed almost anywhere inside a property and run on natural gas or LPG, making it perfect for homes with or without mains gas.

How Much Does this Boiler Cost?

Navien’s NCB Combi comes with a 24kW, 28kW, 34kW or 40kW output and costs between £756 and £980 without installation. Combi boiler installation costs vary depending on where you live, the installer rate and how much work is required. If you want to find the best price for a boiler and the installation, you should get a fixed-price quote from different local and national installers. 

How will I know if this Boiler is Suitable for My Home?

Combi or combination boilers don’t require additional components, like tanks in the loft or a hot water storage cylinder in the airing cupboard, making them ideal for homes with limited space. They take water directly from the mains and heat the water you wish to use but can struggle to operate more than one tap at a time. The Navien NCB Combi is available in four sizes and is suitable for most homes with one bathroom. 

Choosing a new boiler in the correct size/output is a decision you don’t want to get wrong, so it’s best to ask a Gas Safe registered engineer to visit you in your home and make a recommendation. 

Is it a High Efficiency Boiler?

Yes. The Navien NCB Combi is 92% efficient with an A energy efficiency rating and is an Energy Saving Trust endorsed product. To maximise efficiency, you can have the boiler installed with an optional weather compensation sensor that enables it to run in condensing mode. 

Does this Boiler have a Good Range of Controls and Features?

It does. This combi boiler can be installed almost anywhere in your home thanks to its flexible flue lengths and IPX5 rating. It comes OpenTherm ready and has traditional stainless steel and brass components to prevent corrosion and increase your boiler’s lifespan. The NCB Combi from Navien boasts a 10:1 modulation ratio and comes complete with a blue touchscreen control to allow you to manage your heating and hot water temperatures. The touchscreen control also has an ECO button, which delivers water and energy savings and provides your Navien service engineer with details of how efficiently your boiler is performing. 

How long is the Warranty on this Boiler?

The Navien NCB Combi comes with a 7-year warranty to give you peace of mind that you’re covered should the boiler break down due to failure of components. 

Summary of Important Information

  • Expect to pay between £756 and £980
  • Heating output of 24kW, 28kW, 34kW or 40kW
  • Hot water flow rate of 13.8, 16.1, 19.5 or 22.9 litres per minute
  • 24kW and 28kW unit dimensions: 695mm (H) x 440mm (W) x 358mm (D)
  • 34kW and 40kW unit dimensions: 695mm (H) x 440mm (W) x 408mm (D)
  • Uses gas or LPG as its fuel source
  • A-rated for efficiency
  • 7-year warranty as standard

Pros and Cons

Before you rush to buy the Navien NCB Combi, it’s worth weighing up the advantages and drawbacks and getting some advice from a qualified heating engineer. You can find the pros and cons of getting this combi boiler installed below. 


  • Considerably cheaper than some other boiler brands
  • Suited to small, medium and large-sized homes with one bathroom
  • Class-leading flue lengths and IPX5 rating – siting flexibility
  • Easy to install, use and service
  • Built-in frost thermostat
  • Blue touchscreen control – gives you full control of heating and hot water temperatures
  • OpenTherm ready – gives instant access to the latest control technology
  • Integrated primary and secondary stainless steel heat exchangers – prevents corrosions and helps extend the lifespan of the boiler
  • Optional outdoor weather sensor – regulates the heating temperature according to changes in outside temperatures and enables the boiler to run in condensing mode
  • Self-diagnosis and error feedback feature – offers a quick troubleshooting guide
  • Provides maximum energy efficiency – reduce fuel bills and carbon emissions
  • Energy Saving Trust endorsed product
  • Great rating on Trustpilot – correct at the time of writing – February 2022
  • 7-year parts and labour warranty


  • None
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