Keston Boilers Reviews & Prices 2023 Re January 20, 2023

Keston Boilers Reviews & Prices 2023

Heating engineer fitting a boiler

Who are Keston boilers? We’ll discuss the history, products, costs, and warranties and give you an overall view of them.

When it comes to having to splash out on a new boiler, we understand that our customers want to spend their money wisely. That’s why we always advise our customers to shop around before buying a new boiler.

If you were thinking about buying a new Keston boiler, you’ll be glad to know that we’ve put together a complete guide to help you know if it’s the right boiler for your home. Here, we will discuss Keston’s history, products, costs, and warranties and give you the final verdict.

Keston Boiler History

Keston was originally established in 1928, creating domestic and commercial boilers. 

In 2006, Keston was acquired by Ideal Heating.

Keston boilers have been manufactured in Ideal’s Hull site since 2013. 

As an Ideal owned company, you can expect a high level of customer service.

Keston Boiler Range

Keston British-made combi, system and conventional boilers are developed and manufactured to the highest standards. If you want to know the difference between these boiler types, read our blog

Keston helps you go the distance, with the ability to run a boiler flue pipe vertically or horizontally and extend it up to 27 metres – quite impressive! 

Keston Combi Boilers

Combi boilers (combination boilers) are the most common type of boilers found and installed in the UK. In fact, over half of all boilers installed in the UK are combi boilers. The name combination boiler comes from their ability to combine heat and hot water in one little white box!

Combi boilers are connected directly to the mains water supply coming into your home, they heat this water directly, eliminating the need for a separate water tank (as with a system or regular boiler). This saves a great deal of space, especially in flats and smaller homes.

Combi boilers also supply hot water at mains pressure, which allows you to enjoy mains pressure showers without needing to install a shower pump.

Combi boilers keep a small reservoir of pre-heated water within them to ensure they can supply hot water to taps instantly. Head over to our how do combi boilers work blog for more details.

Keston Combi Boiler Range

1. Keston C30 Combi Gas Boiler

Like any other combi boiler, the Keston C30 combi boiler combines both the water heater and the central heating in one unit, removing the need for any additional hot or cold water tanks.

The C30 combi boiler has an efficiency rating of 89.6% and an ErP A-rating for central heating and hot water, meaning that depending on the efficiency of your current boiler, this combi boiler could potentially help you lower your energy bills.

With an output of 25.6kW for central heating and 30.3kW for hot water, the C30 combi boiler is ideal for homes with 15 radiators and up to 2 bathrooms. 

Keston boilers are typically used in compact spaces such as smaller flats/properties in locations such as London. This is because Keston boilers offer a twin flue system which makes every job easier. To give you maximum flue flexibility, the flue can run vertically or horizontally from a height of 1.5 degrees and the flue can be extended up to 27 metres from the boiler.

This allows for hassle-free and easy installation and means that your new boiler can be installed in the most practical and convenient space in your home.

2. Keston C35 Combi Gas Boiler

The Keston C35 combi boiler also has an efficiency rating of 89.6% and an ErP A-rating for central heating and hot water. With an output of 25.6kW for central heating and 35.3kW for hot water, the C35 combi boiler is ideal for homes with 20-25 radiators and 2 bathrooms.

Keston Combi Boiler Features

  • 7-year warranty
  • Easy to see pressure gauge
  • Large backlit display with user-friendly controls
  • Low lift weight
  • Low component count maximising reliability
  • Compact dimensions
  • Twin flue up to 27m
  • 50mm muPVC (PVC-C) solvent weld flue allowing simple, cost-effective installations
  • Weather compensator supplied as standard making Keston Combi Boiler Plus compliant out of the box
  • Pre-fitted filling loop
  • Inbuilt frost protection
  • Fully modulating
  • LPG conversion kit available

Keston Combi Boiler Prices

Keston Combi Gas BoilerWarrantySizes


(inc VAT)

Keston C30 Combi7 years 30kW£1,400
Keston C35 Combi7 years 35kW£1,480

Keston System Boilers

System boilers can usually be found in homes that have a high requirement for hot water. They work by heating water in a separate storage tank from the boiler, usually found in an airing cupboard, this hot water is then available for use in multiple bathrooms if needed.

In practice, you can have two baths running in separate bathrooms and they will both get hot water without affecting the heating of your home.

This differs from a combi, as a combi heats water directly from the mains supply and doesn’t store hot water. Click the link if you want to know how system boilers work in detail.

Keston S30 System Boiler

The Keston S30 has an efficiency rating of 89.5% and an ErP A-rating for heat, meaning that although this system boiler is not the most efficient boiler on the market, it could still help lower your energy bills, depending on your current heating system.

With an output of 30kW for central heating, this system boiler can comfortably heat a medium-sized up with up to 20 radiators.

Keston S30 System Boiler Features

  • 7-year warranty
  • Easy to see pressure gauge 
  • Large backlit display with user-friendly controls
  • Low lift weight
  • Low component count maximising reliability
  • Compact dimensions
  • Twin flue up to 27m
  • 50mm muPVC (PVC-C) solvent weld flue allowing simple, cost-effective installations***
  • Weather compensation supplied as standard
  • Inbuilt frost protection
  • Fully modulating
  • LPG conversion kit available

Keston S30 System Boiler Prices

Keston System Gas Boiler




(inc VAT)

Keston System S307 years 30kW£1,217

Keston Conventional Boilers

Conventional boilers – also known as regular, traditional, heat only or open vent boilers, are the most difficult to install or replace. A regular boiler includes both a hot and cold water storage tank, the boiler itself, and an expansion cistern located next to the cold water tank. This takes up quite a bit of space in a home and it’s usually preferable to switch to a combi so that these tanks can be removed.

Similar to system boilers, regular boilers are able to supply large amounts of hot water simultaneously to multiple bathrooms due to the hot water storage tank facility. Want to know more about how conventional boilers work? You guessed it. We have a blog that covers this!

Keston Conventional Boiler Range

Keston Heat 2

Keston Heat 2 comes in 45kW and 55kW output which makes it the perfect choice for both Large Domestic and Commercial installations.

Supported by 5-year parts and labour warranty and Free Commissioning, Keston Heat 2 is a reliable and efficient wall hung solution. The quality of this product range has been developed through meticulous design, careful component selection and proving; leading to reliability and longevity. The range provides high efficiencies for both home and business owners, ensuring reduced running costs. This is coupled with low NOx emissions, giving Keston Heat 2 a Class 6 rating.

Keston Heat 2 Features

  • 5-year warranty
  • Free Commissioning
  • Low NOx Class 6
  • Inbuilt weather compensation
  • Inbuilt pump (low energy modulating)
  • Twin flue up to 18m
  • New Air Inlet Kit for Open Flue (B23) installations
  • High 5:1 turndown
  • Small installation footprint
  • 50mm muPVC (PVC-C) solvent weld flue allowing simple, cost-effective installations
  • Cascade controls option
  • Easy servicing with 3 removable sides 
  • Built-in, serviceable Non-Return Valve

Keston Heat 2 Prices

Keston Heat 2 BoilerWarrantySizes


(inc VAT)

Keston Heat 457 years 45kW£2,543
Keston Heat 557 years 55kW£2,848

Keston Boiler Customer Reviews

Keston’s Trustpilot page has a trust score of 2.4 out of 5, but there are only 35 reviews on Trustpilot; as you can imagine, this is not enough to go on. 

71% of reviews are in the ‘bad’ section, which is never good.

Keston Boiler Error Codes/Fault Codes

As with all appliances, over time, your boiler’s efficiency will naturally decline slightly, however, ensuring that your boiler has an annual service will help to prevent your boiler from suddenly breaking down on you, as well as expensive repair costs.

Keston Boiler Warranty

Every boiler manufacturer offers a standard warranty/guarantee with their boilers which lasts between 1-10 years. Boiler warranties are there for extra peace of mind, however, they do vary depending on models and boiler brands. 

Warranty is one of the key factors we look for when purchasing a new or replacement boiler, and can often be the deal-breaker when it comes to choosing the right boiler for you. 

Keston offers a standard 7-year warranty on their boilers, but make sure to read their T&Cs first to know what could invalidate your boiler warranty.

Should I buy a Keston boiler?

We’ll cover the positives of Keston boilers first to see whether or not it’s worth buying one.

One of the advantages of Keston boilers is the ‘twin flue system’. Every Keston boiler has two flue holes to make installation simpler and give heating engineers maximum flexibility. This may not be a massive draw as a customer, but if your boiler is in a tricky position, it could be a good choice to help your engineer out.

The twin flue system can be extended up to 27-metres from the boiler. So if you have a massive home or you just enjoy a massive flue run then this is the boiler for you.

Another advantage Keston has is that they have the same customer service department as Ideal boilers, which is really good. So if you have an issue and you need to speak to someone, you can. They are pretty proactive at getting out to jobs as well.

Keston isn’t the cheapest boiler brand out there, despite not being a massively reliable boiler. You may be better off just going with an Ideal which is similarly priced but generally much more reliable.

Depending on the model of Keston boiler you choose, you can get up to seven years’ warranty, which gives you peace of mind when you buy a Keston boiler it will last for a decent amount of time.


Here’s our final verdict: 

We wouldn’t recommend a Keston boiler unless you need to run a flue from a boiler located in a difficult position and you don’t want the hassle of moving the position of the boiler. This can be useful for boilers located in basements or in flats where the flue is located in the void.

Keston has a very limited range of combi, regular, and system boilers with a limited choice of kW outputs.

Time to pull the plug on your old boiler?

If you’re looking for a budget boiler we would recommend the Worcester Bosch 2000 series, the scaled-down younger sibling of the Worcester Bosch 8000 series. Sure, it doesn’t have all the bells and whistles of the 8000 series, but it’s a very reliable boiler, from a top manufacturer – which means you’ll get great aftercare.

The Ideal Logic range is also a great option if you don’t want to spend a lot on a new boiler. It’s reliable, and efficient, and it comes with an impressive 8-year warranty.

If you’re shopping around for a new boiler, check out our boiler comparison tool.

Just select up to 3 boilers you want to compare and you’ll be able to compare key stats side by side to see which Keston (or another boiler brand) is best for you.

The short answer is no because there are better options available for the same or less money.

They offer limited boiler sizes and models.

The twin flue system is useful but only in very specific situations.

Keston boiler prices vary depending on the boiler size and model. For example, the Keston 30C (30kW) combi boiler costs £1,400 (without installation).

From the same online plumbing merchant, a Worcester Bosch 4000 (30kW) combi boiler costs £1000. A pretty big saving and you get a mid-range Worcester Bosch boiler from a model that was first released in 2021.

A WarmZilla boiler comes with the boiler, Gas Safe installation, system filter, system cleanse, inhibitor, wireless thermostat, up to 14 years guarantee, any flues or extension kits you may need; plus if your condensate or gas pipes require upgrading – that’s included in your fixed price boiler quote too!

You can get a quote now on a new boiler with all the extras, in a few minutes using the WarmZilla online survey.


*Average boiler prices were taken from an online heating supplier on 5/5/22. Prices are for the boiler alone (including VAT) and may be subject to change. 

Prices don’t factor in the cost of installation.

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