For properties with around 10 radiators and 2 bathrooms the best 24kW system boilers will comfortably provide enough central heating and domestic hot water. Our list of the best 24kW system boilers includes:
ATAG i24S
Baxi 824
Ideal Logic Max
Potterton Assure
Vaillant ecoTEC Plus 624
Worcester Bosch Greenstar 24i
Is a 24kW system boiler suited to my home?
A system boiler takes water directly from the mains, heats it up and then either circulates it around the central heating system or to the hot water cylinder, where it is stored until needed. As system boilers store hot water in a cylinder, they're perfectly suited to homes with a high demand hot water.
A fully-qualified heating engineer is the best person to recommend the most suitable heating system for the central heating and domestic hot water demands of your home. By completing our simple online form, you can get free quotes from engineers in your area.
The best 24kW system boilers
When looking for the best 24kW system boiler there are plenty to choose between.
Best 24kW System Boilers
Seasonal Space Heating Efficiency
ErP Rating
Warranty
ATAG i24S
94%
A
10 years
Baxi 824
93%
A
10 years
Ideal Logic Max
94%
A
10 years
Vaillant ecoTEC Plus 624
94%
A
5 years
Worcester Bosch Greenstar 24i
94%
A
7 years
ATAG i24S
ATAG are well known for the lengthy 10 year warranties they attach to all of their boilers, which shows exactly how much faith they have in their performance. As well as the warranty, the efficiency is amongst the highest when it comes to comparing the best 24kW system boilers, which will help to save you money on your energy bills.
Built-in ErP pump which ensures that the boiler is able to deliver the most efficient performance at all times
Compact dimensions that make it perfect for a cupboard fit (h700 x w440 x d355)
Simple to use controls
Extensive 10 year warranty
The ATAG iS range of system boilers also includes output ratings ranging from 15 kW right up to 40 kW.
Baxi 824
Baxi 800 system boilers are manufactured in the UK and are fitted with brass components of the highest quality. Baxi boilers are well known for their reliability and also perform to a highly efficient level.
Includes high-quality brass components
Fitted with an Adey Micro2 magnetic system filter which increases performance and helps to protect the unit
OpenTherm ready which makes it possible to take control of the heating from your smartphone or tablet
A low lift weight (29.5kg) could help to lower the installation costs
Available with a lengthy warranty of 10 years
An 18kW model is also available in the Baxi 800 range of system boilers.
Ideal Logic Max
Ideal's Logic Max range of system boilers build on the standards set by the Logic Plus to deliver an efficient, high performing heating system that's covered by a lengthy warranty.
A large digital display makes it easier to know exactly how your boiler is performing at any one time
Has a frost protection feature which will keep the heating running through even the coldest of conditions
Fully compatible with Ideal heating controls
Extensive 10 year warranty
The Logic Max range includes a number of outputs, with 15kW, 18kW and 30kW models all available in addition to the 24kW unit.
Vaillant ecoTEC Plus 624
Vaillant ecoTEC boilers are well known for their efficiency, which comes largely thanks to the stainless steel heat exchanger.
A stainless steel heat exchanger increases efficiency and will help to extend the life of the boiler
Built in two stage frost protection for reliable performance all year round
Quiet Mark accreditation which guarantees quiet performance during operation
Compact dimensions of 720 x 44 x 335 (HxWxD)that make it suitable for a cupboard fit
Wide modulation range of 1:6 which will help to increase efficiency and lower your energy bills further
Should a 24kW system boiler not be suitable for your home then the Vaillant ecoTEC Plus range of system boilers also includes lower outputs of 12, 15 and 18kW as well as larger outputs of 30 and 37 kW.
Worcester Bosch Greenstar 24i
Worcester Bosch has become one of the most popular boiler manufacturers in the UK and their Greenstar range is the most efficient yet.
Recycles heat from exhaust gases (would otherwise be lost) and modulates the output which can make the running costs 30% cheaper than some older boilers
Compatible with Greenskies solar panels which will heat the water in the cylinder using free renewable energy from the sun – further reducing your energy bills
The 24kW model is the highest output available in the Greenstar i range so if you're looking for a lower output then 9kW, 12kW, 15kW and 18kW outputs are also available.
A system boiler is likely to cost around £1,000 for the unit but you will also need to factor in the hot water cylinder as well as the installation too.
ATAG don't publish the price of their boilers but are likely to be the most expensive. The boilers from Baxi and Ideal are potentially the most affordable.
Best 24kW System Boilers
Potential Cost (before installation)
ATAG i24S
£2,000+
Baxi 824
£924
Ideal Logic Max
£915
Vaillant ecoTEC Plus 624
£1,000
Worcester Bosch Greenstar 24i
£995
Best 24kW system boilers for off-grid homes
A natural gas boiler isn't suitable for properties that aren't connected to the gas grid so if you live in an off-grid home then options include Liquified Petroleum Gas (LPG) and oil. Fortunately, some of the best 24kW system boilers are LPG compatible.
Best 24kW System Boilers
LPG Compatible?
ATAG i24S
Yes
Baxi 824
No
Ideal Logic Max
No
Vaillant ecoTEC Plus 624
No
Worcester Bosch Greenstar 24i
Yes
Only a couple of the best 24kW system boilers run on LPG so you might want to consider an oil boiler too. The Viessmann Vitorondens 200-T would be a suitable heating system.
Best 24kW System Oil Boilers
Seasonal Space Heating Efficiency
ErP Rating
Warranty
Viessmann Vitorondens 200-T
97%
A
10 years
Benefits of installing a system boiler
If you're looking for a modern heating system than a regular boiler (also known as conventional and heat-only boilers) then your choice comes down to a system or combi. While a combi is a compact cost-effective solution that doesn't need a water tank, system boilers are the better choice for homes with multiple bathrooms. These are some of the benefits of installing a system boiler:
If you have a regular boiler then a system boiler is a more modern alternative that is comes fitted with a pump to provide a quicker response when you turn the central heating on
As hot water is stored in a cylinder, they can meet higher demands for domestic hot water
Able to deliver hot water to more than a single bathroom at any one time without a drop in pressure
If you have a solar thermal system (or are considering one) then you can install a solar-compatible cylinder installed to help lower your energy bills
Looking to install a system boiler with a different output rating? Take a look at our other comparison articles:
Finding a heating engineer to quote and install on your new boiler has never been easier. Using Boiler Guide, you can get free quotes from up to 3 heating engineers who are based in your local area.
