James Elston
Published April 9, 2024
A 40kW system boiler is particularly suitable for larger households with several rooms and approximately 20 radiators that require domestic hot water and heating. When deciding which boiler output best suits your needs, you should consider factors such as the size of your property, the number of bedrooms and the number of bathrooms.
This article will explore why selecting the best 40kW system boiler is essential and provide insights into the top-rated 40kW boilers that can help you make an informed decision.
Contents
Top 6 40kW System Boilers Of 2024
Let’s review the top-rated 40kW system boilers for 2024.
1. ATAG I40S 40kW System Gas Boiler
Specs:
Based in the Netherlands, ATAG manufactures high-quality boilers made with stainless steel and brass components and precision engineering techniques. All of ATAG’s boilers are rated A for efficiency.
The ATAG I40S 40kW System Gas Boiler is an efficient heating solution for large homes with space and high hot water demand.
This system boiler, measuring 700 x 440 x 355 mm, can be easily wall-mounted and offers an output of 38.8kW, making it suitable for homes with greater heating needs. There are also smaller output options starting from 15kW, providing flexibility to meet different needs.
One outstanding feature of the ATAG I40S is its performance, which enhances the comfort of the living area. Its user-friendly controls further contribute to its appeal by giving homeowners control over the boiler’s operations.
The unique iCon heat exchanger comes with a lifetime replacement guarantee, adding a level of confidence in the reliability of the unit. It also features quality steel and brass components, ensuring its strength and durability.
It’s important to note that the ATAG I40S may require space for a water cylinder. The limitation on the size of the tank might impact the amount of water, so it could be necessary to add insulation to the tank to avoid wasting heat and energy.
2. Vaillant ecoTEC plus 637 System Gas Boiler
Specs:
Vaillant is based in Germany and has been manufacturing heating and cooling products since 1874. Its extensive range of boilers is known for its innovative technology and durable stainless steel heat exchangers.
For homes with five to six bedrooms, the Vaillant ecoTEC Plus is a great choice as it offers a powerful heating solution.
The ecoTech Plus comes with a standard seven-year warranty. You also have the option to get an extended warranty of 10 years at an extra cost.
Vaillant ecoTEC’s A-rated efficiency and two-speed automatic pump contribute to energy savings and minimising heat loss.
The stainless steel heat exchanger ensures durability. This system boiler also seamlessly blends in with the home as a floor-standing unit.
3. Mistral Sealed System CS4 41kW Oil Boiler
Specs:
Mistral is a specialist oil-fired boiler manufacturer that produces a range of condensing and non-condensing boilers. Based in the UK, their products are highly regarded for their durability and quiet operation.Â
The Mistral Sealed System CS4’s output of 41kW is ideal for homes with higher heating demands and hot water needs. This boiler offers flexibility, with options for condensing and non-condensing models as well as indoor and outdoor units.
The boiler features include a circulating pump, a 12-litre expansion vessel and a safety valve. One potential drawback, however, is that it only comes with a two-year warranty with no option for extended warranties.
This particular oil boiler from Mistral is designed to be placed under kitchen worktops, making it a suitable choice for smaller homes.
Since it is a flooring unit, this oil boiler requires additional space for a hot water cylinder.
Â
4. Viessmann Vitodens 100-W 35kW
Specs:
Viessmann are another high-quality boiler brand based in Germany. Viessmann boilers are becoming increasingly popular due to the diversity of the range and the company’s focus on green technology.
This system boiler’s design includes hydrogen capabilities and built-in WiFi catering. An LCD touchscreen enhances user experience, allowing navigation and control. With its 1:6 modulation ratio, it can also adjust according to the home’s heating demands.
This boiler is known for its durability thanks to features like the MatriX Plus burner, steel MatriX surface, and impressive lifespan of 15 to 20 years.
Overall, the Viessmann Vitodens 100-W 35kW is a technologically advanced option for those who need a high-capacity system boiler.
5. Intergas Compact HRE SB 40
Specs:
Intergas boilers are known for their versatility and the company has become famous for integrating cutting-edge tech into their products. The Intergas Compact HRE SB 40 is a condensing and wall-mounted system boiler with an output rating of 42.5kW. If you want to learn more about condensing boilers, check out our comprehensive guide.Â
One of its standout features is its versatility – you can heat water by adding a storage cylinder. The warranty on the heat exchanger (10 years) and parts (two years) provides added peace of mind regarding its durability.
Another advantage is that it doesn’t have an air pressure switch, which adds to its adaptability as well as the choice between horizontal and vertical flue options.
The Intergas Compact HRE SB 40 works well for properties with moderate hot water and heating demands. It can accommodate both on/off thermostats and programmable room thermostats, making it flexible regarding temperature control. Additionally, it has built-in boiler frost protection, which proves useful during winter months.
6. Worcester Bosch Greenstar 8000 Life
Specs:
Worcester Bosch is one of the most well-known and well recommended boiler brands in the world. Its manufacturing is of the highest quality and the performance of its boilers is praised by customers and engineers alike.
The Worcester Bosch Greenstar 8000 Life stands out as a technologically advanced option if you prioritise performance and convenience for your heating system.
It has a 94% Energy-related Product (ErP) efficiency rating and is suitable to supply hot water to multiple bathrooms. Its compact design allows for wall hanging and it can be easily controlled with smart technology controls. The Greenstar smart filling system ensures that pressure is maintained at a practical level for users.
How We Chose The Best 40kW System Boilers
Here’s how we determined which boilers should appear on our list.
Customer reviews
To create our list, we assessed boilers based on a set of criteria such as energy efficiency, versatility, and pricing. One of the ways we evaluated this was by finding customer reviews of boilers on sites like Trustpilot.
We looked out for reviews containing keywords that related to our criteria and then checked the ratings customers were giving boilers for specific specs and features. This allowed us to establish plenty of data on a boiler’s overall performance.
Â
Independent testing bodies
We also analysed the test results from independent bodies like Which? to see how different boilers compared to each other. If a boiler was highly rated by customers and performed well in these impartial tests, then it had a good chance of being included in the list.
Â
Comparing The Best 40kW System Boilers: What Sets Our Top Picks Apart
Our top pick for a system boiler would be the Viessmann Vitodens 100 W. It stands out for its energy efficiency, affordability and advanced technology.
Another option to consider is the Worcester Bosch Greenstar 8000 Life. It offers smart technology controls and has a high-efficiency rating, making it a valuable investment.
The Intergas Compact HRE SB 40 is also worth considering if you’re looking for a budget-friendly system boiler.
How Much Does A System Boiler Cost?
A 40kW system boiler can start at £1,000. However, this price doesn’t include the installation of a hot water cylinder.
Typically, installation prices average around £3,000. However, keep in mind that final costs can vary based on the type of boiler, its complexity, and where it needs to be installed.
Some factors can impact the expenses of installing system boilers:
- Installation complexity: The complexity of your existing heating system in your home can affect the installation costs.
- Location and access: The geographical aspects and how easily accessible the installation site is.
- Property size: For instance, if you have heated rooms, you might require additional radiators.
The installer rates, fuel type, boiler brand, size of pipework and radiators, heating controls, and labour costs can also affect the final cost of installation.
What To Consider When Choosing The Best 40kW System Boiler
When selecting a system boiler for your home, it’s important to consider the following points:
Read reviews and compare brands and models of 40kW system boilers, considering their pros and cons. It’s also essential to align your budget with the boiler you are considering and factor in installation costs.
Take the next step in your home heating journey and get a personalised quote or advice from Eco Happy today.
FAQs
How long does it take to install a system boiler?
This largely depends on how complex the installation is. For example, if it’s just a like-for-like swap then it may only take around four to six hours to install a system boiler. However, if it’s a complete system upgrade and your boiler will be installed in a different location to your old one, it could take one to two days.
Why is a system boiler’s efficiency rating important?
The more efficient a system boiler it is, the more energy is converted into usable heat and the less energy is wasted. This means less energy is required to heat your home and supply hot water which can reduce your energy bills and your home’s carbon footprint.
Which system boiler is most efficient?
Modern condensing boilers are generally the most efficient to run, resulting in lower energy and heating costs.
Final Thoughts
Selecting a 40kW system boiler is more than making a decision – it’s an investment in the comfort and efficiency of your home. It’s crucial to consider the advantages of choosing the best system boiler, including warmth, energy efficiency and prompt response times. Contact us at Eco Happy. We’ll be happy to assist you with a quote.
James Elston
Boiler Expert
James Elston is the top boiler replacement and heating expert at Eco Happy. He has over 20 years of experience in the industry, focusing on Gas Safe boiler installations and offering home-heating and energy-saving solutions to homeowners across the UK. From sourcing the most energy-efficient combi boiler to providing specialist heating advice, James ensures that Eco Happy maintains the highest standards and best customer service.