The smarter way to replace your boiler

  • Get FREE Quotes today
  • Compare quotes & save money
  • Over 5,000 engineers across the UK
Tell us about your job
Get Free Quotes

Baxi 800 25kW, 30kW or 36kW Combi Boiler

The Baxi 800 Combi is a compact and easy to install combination boiler suited to small, medium and large-sized homes.

Built right here in the UK, the Baxi 800 Combi boasts quality brass components and is small enough to fit inside a standard kitchen cupboard. It comes with a market-leading warranty, can be connected to smart controls and is available in three heat outputs to appeal to homes of all shapes and sizes. Designed with both the installer and homeowner in mind, this combi boiler also meets modern energy efficiency standards and is compliant with Boiler Plus regulations.  

How Much Does this Boiler Cost?

The Baxi 800 Combi can be purchased with an output of 25kW, 30kW or 36kW, and prices range between £940 and £1,150 including VAT. How much this boiler will cost you is dependent on the output you need and which heating engineer or company you choose to carry out the installation work. You also need to factor in the installation cost, so it’s a good idea to shop around and get a range of quotes to find the best deal.      

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

A combi boiler, such as the Baxi 800 Combi, is ideal for homes where space is tight because it takes water directly from the mains supply and therefore doesn’t need separate tanks or a hot water storage cylinder. Even though you can save space with a combi boiler, it will struggle to cope when you want to run more than one bath or shower at the same time. Since this combi boiler comes in three outputs, it’s suitable for small, medium and large-sized homes.

The higher your demand for heating and hot water, the higher the kW output you will need. Choosing the correct boiler type and size for your home is incredibly important, so we recommend you consult a qualified Gas Safe engineer before you purchase the Baxi 800 Combi. 

Is it a High Efficiency Boiler?

Yes, it is. The Baxi 800 Combi is an A-rated boiler that meets the energy efficiency ratings required for Boiler Plus compliance. Boiler Plus is a legislation that was introduced in 2018 to improve the energy efficiency of homes in the UK. It aims to ensure all new gas boilers have an ErP efficiency of at least 92% and are installed with either a flue gas heat recovery unit, a smart load or a weather compensation control. 

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

It sure does. Baxi’s 800 Combi has tough brass hydraulics and comes with an Adey Micro2 magnet system filter to protect both the boiler and heating system. This combi boiler also comes with a simple hanging bracket, a built-in stand-off frame for neat installation and flue options up to 20 metres. And that’s not all. The Baxi 800 Combi is IFOS (In Flue Outdoor Sensor) compatible to comply with Boiler Plus requirements and has an OpenTherm interface to enable you to control your heating from a smartphone or tablet. 

How long is the Warranty on this Boiler?

The Baxi 800 Combi comes with an impressive 10-year warranty to give you total peace of mind. If you fail to register the boiler with Baxi within 30 days of installation, the warranty will be reduced to only 2 years. 

Summary of Important Information

  • Priced between £940 and £1,150
  • Heating output of 25kW, 30kW or 36kW
  • Hot water flow rates of 10.2, 12.2 or 15 litres per minute
  • Dimensions of 700mm (H) x 390mm (W) x 285mm (D)
  • Uses gas as its fuel source
  • A-rated for efficiency
  • Smart compatible
  • 10-year warranty as standard

Pros and Cons

Baxi says this boiler features components that installers have said they prefer, such as the tough brass hydraulics. It’s clear that the Baxi 800 Combi has been developed with heating engineers in mind, and we believe the boiler meets customers’ needs and expectations too. It’s also worth mentioning that Baxi managed to increase its overall Which score to 71% in 2020, scoring four out of five stars across all but one category. As there are no disadvantages to getting this boiler installed, you can find a list of pros below. 


  • Baxi boilers have an overall Which? score of 71%  
  • Fits in a standard kitchen cupboard
  • Suited to small, medium and large-sized homes 
  • No need for separate cylinder or loft tanks
  • Built using top-quality components
  • Adey Micro2 magnetic filter system to protect the boiler
  • IFOS compatible
  • Compatible with uSense smart room thermostat – can monitor your energy use and control your heating using a smartphone or tablet, wherever you happen to be
  • Provides maximum energy efficiency – reduce fuel bills and carbon emissions
  • 10-year parts and labour warranty
Get Baxi Boiler Quotes

Get quotes to supply a new Baxi boiler now