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Navien NCB System Boiler

The Navien NCB System is a highly efficient and reliable boiler, perfect for homes with a high demand for hot water.

Energy-efficient and easy to use, the Navien NCB System boiler is a condensing unit available in a range of heat outputs to meet your needs. It has excellent features, such as its touchscreen control, and uses natural gas or LPG straight out of the box to suit your requirements. Ideal for homes with high hot water demand, the NCB System with total siting flexibility boasts an A efficiency rating and could help to save you money on your energy bills. 

How Much Does this Boiler Cost?

The Navien NCB System is available with a 20kW, 23kW, 28kW, or 33kW output and will set you back anything between £719 and £942, but you also need to add on the installation cost. System boiler installation costs vary enormously, depending on where you live, the installer rate and the work involved. If you get a fixed-price quote from different local and national installers, you can compare prices for a new boiler and the installation. 

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

This system boiler from Navien is compact and lightweight but requires a separate cylinder for storing hot water, meaning it will take up more space than a combi boiler. Most people keep the hot water cylinder inside an airing cupboard. The NCB System is suitable for small, medium and large-sized homes with more than one bathroom and high demand for hot water.  

Before purchasing the Navien NCB System, you must determine the correct size/output for your requirements. As a general rule, the more radiators, taps, showers and baths you have, the more powerful boiler you need. If you’re unsure, consult with a qualified heating engineer before making your decision. 

Is it a High Efficiency Boiler?

It is. The Navien NCB System is an A-rated boiler with a 92% efficiency rating, so it should help reduce your carbon footprint and energy bills if your current boiler is old and inefficient. This system boiler is also endorsed by the Energy Saving Trust. 

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

Yes. The boiler’s compact dimensions, flexible flue lengths and IPX5 rating mean it can be installed almost anywhere in your property, including on the wall or inside a standard kitchen cupboard. It comes complete with integrated and secondary stainless steel heat exchangers to prevent corrosion and extend the boiler’s life, as well as a stylish touch-type control panel to give you full control of heating and hot water temperatures. The boiler also benefits from a full-text display and an ECO function that allows water and energy savings.

How long is the Warranty on this Boiler?

The NCB System comes with a 7-year warranty. That means that Navien will rectify any manufacturing defect that occurs within seven years of the installation, as long as your boiler is serviced yearly by a qualified heating engineer.  

Summary of Important Information

  • Expect to pay between £719 and £942
  • Heating output of 20kW, 23kW, 28kW, or 33kW
  • 20kW and 23kW unit dimensions: 695mm (H) x 440mm (W) x 358mm (D)
  • 28kW and 33kW 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

Like all system boilers, the Navien NCB System requires more space than a combi boiler because it requires a hot water storage cylinder. But it is more powerful than a combi and can meet the needs of a household with a high demand for hot water. Below are the pros and cons of getting this system boiler installed. 


  • Considerably cheaper than some other boiler brands
  • Suited to small, medium and large-sized homes with multiple bathrooms
  • 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
  • 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


  • Requires separate cylinder
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