Baxi Platinum Combi Boiler Review
Baxi's top of the range boiler

Company type: Manufacturer

HQ: Warwick, England

Founded: 1866

CEO: Karen Boswell

The Baxi Platinum combination boiler is Baxi’s top of the range boiler. It is reliable, easy to install, and with sizes to suit most properties, it is easy to see what makes it a firm favourite with households and boiler installers. Let's find out what else makes the Baxi Platinum combination boiler such a good choice.

Baxi Logo

What Baxi Platinum combi boilers are available?


The Baxi Platinum combi boiler is available in four different sizes: 24kW, 28kW, 33kW, and 40kW.

Boiler size (output)

When talking about boiler “size”, we are referring to the boiler’s power output, which is measured in kilowatts (kW). In simple terms, how much power the boiler uses to heat your water and central heating.

As a general rule of thumb, the more heat and hot water a property needs, the higher the boiler’s power output needs to be.

Hot Water Output Central Heating Output
Baxi Platinum 24 24 kW 24 kW
Baxi Platinum 28 28 kW 24 kW
Baxi Platinum 33 33 kW 28 kW
Baxi Platinum 40 40 kW 32 kW

Other than the different power outputs, the main difference between each Baxi Platinum combi boiler is its flow rate.

Flow rate

Baxi Platinum combi boilers are available with flow rates ranging from 9.8 litres per minute to 16.4 litres per minute, depending on the model.

Baxi Platinum model Flow Rate
Baxi Platinum 24 9.8 litres per minute
Baxi Platinum 28 11.5 litres per minute
Baxi Platinum 33 13.5 litres per minute
Baxi Platinum 40 16.4 litres per minute

A boiler’s flow rate refers to how much hot water your boiler can send to your hot water taps or showerhead in one minute. A good flow rate for a shower is between 10 and 15 litres per minute.

Generally speaking, the more hot water outlets in your home, the higher the boiler flow rate you will need. This is especially the case if your household tends to use multiple water outlets at the same time.

You can find out which Baxi Platinum combi boiler is the most suitable for you further down in this article.

Baxi Platinum combi boiler key features

Can be installed in places where some other boilers can’t

Thanks to its compatibility with Baxi’s Multifit flues, Baxi Platinum boilers can be installed further from an outside wall, in places where other boilers might not be able to be installed.

A boiler flue is the outlet through which steam and toxic gases are safely expelled, and Baxi’s Multifit flues are available in a variety of lengths, bends, and accessories.

Such compatibility with a wide range of flues gives boiler installers more choices when it comes to choosing a new location for your new Baxi Platinum boiler.

Easy to repressurise your central heating system


The Baxi Platinum combination boiler is equipped with an easyfill filling loop, making it easier for households to repressurise their central heating system.

A filling loop is a pipe that connects the central heating system to the mains water supply and is used to fill your heating system with the water it needs to top it up if the pressure has dropped.

Unlike some detachable filling loops that can be difficult to attach and operate, Baxi Platinum boilers are equipped with an easyfill filling loop.

An easyfill filling loop is a permanently attached pipe that allows water into the system via the simple use of a lever. Simply hold down the lever to allow water into the heating system and release it once the boiler pressure is back to normal.

For a more in depth read about Baxi filling loops and Baxi boiler pressure problems, click here.

Exceptional flow rate on the Baxi Platinum 40

The Baxi Platinum 40 boasts an impressive flow rate of 16.4 litres per minute. A good flow rate for a shower is between 10-15l/min, so with a flow rate of 16.4l/min, the Baxi Platinum 40 is strong enough to cope with high hot water demands in larger households.

Along with the Baxi Duo tec, the Baxi Platinum 40 has the highest flow rate of any Baxi combination boiler.

Such a high flow rate could increase shower performance, lower the time it takes to fill up your bathtub, and allow more than one water outlet to be used at the same time without a significant drop in water flow.

Built-in frost protection

Baxi Platinum combi boilers are equipped with a built-in frost thermostat to help prevent the water in your central system from freezing. The water in boilers installed in colder parts of properties, such as the garage or loft, is prone to freezing if temperatures drop low enough.

If the water in your boiler freezes, then the boiler is at risk of a breakdown, which could cost you hundreds in boiler repairs, or you may even need a boiler replacement, which could cost a few thousand pounds!

Thanks to its built-in frost protection feature, a Baxi Platinum combi boiler will detect when the temperature has dropped to a critically low level and will ignite in order to send hot water around the central heating system until the risk of freezing has been avoided.

Let us fix your boiler.

At Smart Plan we have thousands of engineers up and down the country who are ready to fix your issue. We guarantee an engineer to your property within 48 hours.

OR 020 8146 3960

10 year warranty


To give homeowners peace of mind, the Baxi Platinum boiler range comes with a 10 year extended warranty, which is the maximum warranty length Baxi has to offer. Baxi offering their longest warranty period shows the confidence they have in the performance and reliability of their Platinum combi boiler range.

To find out more about Baxi warranties, click here.

Give your boiler a service.

Make sure you don't invalidate your warranty. Call Smart Plan to get a boiler checkup to see if everything is in good working order.

OR 020 8146 3960

How energy efficient are Baxi Platinum combi boilers?


With an ErP rating of A, Baxi Platinum combi boilers are highly efficient boilers.

ErP stands for Energy-related Products and is part of a directive set out by the European Union to reduce greenhouse gas emissions by improving the performance standards and efficiency of all products that consume energy, such as appliances like boilers.

Energy-related Products are rated from A-G, with A rated products being at least 90% efficient and G-rated products being below 70% efficient.

As the Baxi Platinum combi boiler is an A-rated boiler, it uses at least 90% of its energy to heat up your home and water and only wastes a small amount of fuel in the process. To put this into context, many UK households are still using older boilers that are only 70-80% efficient, which means that up to 30% of their boiler’s energy will be wasted instead of being used to heat up their homes!

Being so efficient means that Baxi Platinum combi boilers don’t need to run as long to heat up your central heating and water, which could result in you saving money on your energy bills!

How big is a Baxi Platinum combi boiler?

Baxi Platinum combi boilers are 780mm high, 450mm wide and 345mm deep, making them too big to be classified as compact boilers. Compact boilers are boilers that are small enough to fit into a standard kitchen cupboard.

Although Baxi Platinum combi boilers are not compact boilers, they can still be easily installed in all the usual places, such as the kitchen, bathroom, airing cupboard, utility room, or any other room, without taking up too much space.

Due to its built-in frost thermostat, it can be installed in colder areas of the property, such as the garage or loft, and its compatibility with Baxi Multifit flues means it can be installed further away from an outside wall.

Is the Baxi Platinum combi boiler suitable for my property?

With the Baxi Platinum combi boiler being available in power outputs ranging from 24kW-40kW and flow rates ranging from 9.8l/min to 16.4l/min, there is a Baxi Platinum combi boiler suitable for most properties.

Power output

Other than the type of boiler, there are three main factors to consider when determining what size boiler is suitable for your property:

  • The number of radiators
  • The number of bedrooms
  • The number of bathrooms

Below is a rough guide to which Baxi Platinum model is best suited to your property based on its power output.

Property Type Suitable Baxi Platinum combi boiler
  • 1-2 bedrooms
  • 1 bathroom
  • Fewer than 5 radiators
  • Baxi Platinum 24
Small house
  • 1-2 bedrooms
  • 1 bathroom
  • 5-7 radiators
  • Baxi Platinum 24
  • or
  • Baxi Platinum 28
Medium house
  • 2-3 bedrooms
  • 1 bathroom
  • 6-7 radiators
  • Baxi Platinum 33
Family house
  • 3-4 bedrooms
  • 1 bathroom
  • 1 ensuite
  • Up to 10 radiators
  • Baxi Platinum 40
Large family house
  • 4-5 bedrooms
  • 2 bathroom
  • 1 ensuite
  • Up to 15 radiators
  • N/A

It is important that you get the correct size boiler for your property and needs. Too small and your boiler will struggle to heat up your home and meet its hot water demands. Too big and your boiler may use more power than necessary, resulting in wasting energy and money.

Does your home have high hot water demands?

Although Baxi Platinum combi boilers come in a range of different power outputs to suit a number of different sized properties, they are not the best choice for larger properties with very high hot water demands. As with all combi boilers, Baxi Platinum combi boilers heat water on demand, and if the demand is too high, the flow rate to each water outlet will be reduced considerably.

If you have high hot water demands, then a Baxi Heat only boiler may be a better choice for you as they store large amounts of hot water in a tank or cylinder for later use.

Flow rate

Baxi Platinum combi boilers come with flow rates ranging from 9.8l/min on the Baxi Platinum 24 to an exceptional 16.4l/min on the Baxi Platinum 40.

Baxi Platinum 24 9.8 l/min
Baxi Platinum 28 11.5 l/min
Baxi Platinum 33 13.5 l/min
Baxi Platinum 40 16.4 l/min

A good flow rate for a shower is between 10-15 litres per minute, which means the Baxi Platinum 24, 28, and 33 will be able to provide you with a good flow of hot water for your showers and baths, but here is where the Baxi Platinum 40 sets itself apart. With an exceptional flow rate of 16.4l/min, the Baxi Platinum 40 is capable of providing a very strong flow of water, even when multiple water outlets are being used at the same time!

We recommend that you get your home surveyed by a Gas Safe registered engineer who will assess your property and heating demands in order to determine the right boiler for your needs.

If you would like to have a new Baxi Platinum combi boiler or any other boiler installed, click here for more information

Baxi Platinum Specifications

24 kW 28 kW 33 kW 40 kW
Width 450mm 450mm 450mm 450mm
Height 780mm 780mm 780mm 780mm
Depth 345mm 345mm 345mm 345mm
Weight 40.2kg 40.2kg 41.7kg 42.2kg
Fuel Type Gas Gas Gas Gas
Energy Rating (Heating) A A A A
Energy Rating (Water) A A A A
Boiler Plus ErP 92% 92% 92% 92%
Flow Rate 9.8 l/min 11.5 l/min 13.5 l/min 16.4 l/min
Central Heating Max. Output 24 kW 24 kW 28 kW 32 kW
Hot Water Max Output 24 kW 28 kW 33 kW 40 kW
Sound Power Level 50 dB 53 dB 52 dB 50 dB
Flue Outlet Position Top Flue Outlet Top Flue Outlet Top Flue Outlet Top Flue Outlet
Warranty 10 years 10 years 10 years 10 years

Still need help with your Baxi boiler?

Call Smart Plan and speak to our expert engineering team free of charge.

0333 772 6247