Which are the best 40kW combi boilers to buy in 2024
Gas combi boilers with 40kW can provide hot water for homes with at least two bathrooms as you mate notice that if you have two showers running at once, you might notice a dropping in water pressure.
If this sounds like your home, you’d be better to get a gas boiler that can supply hot water in high demand such as a system boiler, however, 40kw combi boilers could be the answer.
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A combi boiler has one advantage: it doesn’t require a hot water cylinder. They heat water on demand and then send it to the tap; therefore, you’ll save space, and even better, you can save on your energy bills as you’ll also have hot water on demand, as and when you need it.
Best 40kw combi boilers for central heating output
There are many gas boiler options for you, as all the top boiler manufacturers offer powerful 40 kW combi boilers.
- Worcester Bosch Greenstar 8000 Life
- Baxi 800 Platinum+
- Ideal Vogue Max
- ATAG i40C
What is a powerful combi boiler?
Combi boilers are designed to provide instant heat and hot water to your home. They achieve this by directly connecting to the mains water supply. With this type of boiler, every time you turn on a hot water tap, the combi heats the water from the mains and delivers it to the tap.
However, regular or system boilers store hot water in a cylinder, which means that the cylinder may occasionally run out of hot water, and you will need to wait until it refills with hot water.
Hot water cylinders are useful for fulfilling higher demands, as they can provide hot water to multiple outlets simultaneously. Most combi boilers struggle to meet this requirement unless they have a high domestic hot water output rating, such as the most powerful 40kw combi boilers available.
Read more about storage combi boilers here
Is a 40kW combi boiler the right choice for me?
A 40 kW combi boiler is capable of producing domestic hot water at a rate of 40 kilowatts, making it suitable for households with two bathrooms that have a high demand for hot water.
The output rating of a combi boiler reflects its power and is measured separately for both domestic hot water (DHW) and central heating.
This is in contrast to regular boilers, which only have a central heating output rating because they store hot water in a separate hot water tank.
Are there higher flow rate boilers?
Although there are more powerful combi boilers available with higher flow rates, the most powerful 40kW (DHW) combi boilers can still heat 15-20 radiators, which is generally sufficient.
It is crucial to know the output rating of your new boiler because a boiler that is too powerful will result in higher heating costs, while a boiler that is too weak may not be able to heat your home or provide sufficient hot water.
Homes with more than one bathroom typically require a natural gas system boiler, which has a high energy rating and is capable of providing hot water to two bathrooms simultaneously.
If you are uncertain about selecting the right boiler, don’t worry; numerous Gas Safe heating engineers are available to provide expert advice.
Best combi boilers with the best 40 kW output rating
A Gas Safe registered engineer will recommend a 40kW combi boiler to your home and luckily there are many premium models available. Here are some of the powerful rated combi boilers, however, if you need something lower, then read our best combi boiler guide here for more information.
Worcester Bosch Greenstar 8000 Life 40kw combi boiler
Worcester Bosch’s Greenstar 8000 Lifestyle range includes Style and Life boilers from 30kW to 50kW as well as Style boilers from 30kW to 50kW, which makes them one of the best combi boilers on the market in terms of choice.
The Worcester Bosch 8000 style boilers can be ordered in either gloss black or white, while Life boilers only come in white.
They share many industry-leading features, regardless of whether you have a Style or Life boiler, but the style boilers cost a little bit more for the gloss finish.
- Bosch EasyControl is fully compatible. This allows you to control heating and hot water using your smartphone.
- Modulation at 1:10 to improve efficiency during operation
- One of the best combi boilers available to buy right now
- Greenstar Intelligent filling system means it can top up its own pressure
- Built-in WiFi
- Hydrogen ready combi boiler
- Great looks with their style range
- Great for medium to larger homes with multiple bathrooms
- It can be used with universal smart thermostats
- 12-year guarantee from Worcester Bosch for complete peace of mind
- Very quiet boiler for the size with a low noise level in operation
- Direct replacement for the Greenstar CDI classic
Baxi 800 Platinum Plus 40kw combi boiler
Baxi is a well-known boiler manufacturer, especially among installers. The Baxi 800 Platinum Plus is a great choice for larger homes among their natural gas boilers.
These Baxi boilers run extremely efficiently and will help lower your energy bill with its high ERP water heating efficiency rating.
- OpenTherm technology lets you control your tablet or smartphone via the internet.
- It is well-suited for homes with multiple bathrooms, as it has a flow rate of 16.4L per minute at 35degC temperatures.
- Frost thermostat built-in for winter protection
- Multi-fit flue kit can be used to provide a more flexible installation
- Energy Saving Trust is endorsed
Ideal Vogue Max 40kW combi boiler
Ideal Boilers is well-known for producing premium products, and their Vogue Max range is no exception.
This boiler is made from the finest components. Ideal has a lot of confidence in it, as the warranty can be extended to 12 years.
- If installed by an Ideal Max-certified installer, the warranty period can be extended to 10 to 12 years.
- Boiler frost protection is used to protect the unit from the coldest conditions.
- A combi boiler is lighter than a traditional boiler, making it easier to install. This could help you save money on hiring an installer.
- The LCD display displays clear text messages that describe the problem in the unlikely event of a fault.
ATAG i40C combi boiler
The ATAG i40C combi boiler is a great option for homes with multiple bathrooms. It has a high hot-water flow rate, making it a strong choice. With ATAG boilers, you’ll also benefit from a 10-year warranty that covers the product.
- Use the ATAG One Zone controller to achieve an A+ efficiency rating
- Guaranteed replacement for the iCON stainless-steel heat exchangers
- The flow temperature is automatically adjusted based on outside conditions
- If you have limited space, the dimensions are compact at 700 x 440x 355mm (HxWxD).
- The high flow rate of 16.2 Liters per Minute (at 35C DHW)
- Energy Saving Trust endorses this proposal
How much do 40kW combi boilers cost?
Combi boilers are often the most cost-effective boiler option since they do not require external tanks or cylinders. A 40kW combi boiler can cost as little as £1,300 (excluding installation costs).
The cost of installation varies depending on the heating engineer’s rates, the complexity of the installation, and your location. For instance, installation costs tend to be higher in London than in other regions.
We suggest comparing multiple boiler quotes to ensure the most competitive price for your combi boiler installation. Simply complete the online form, provide details about your job, and receive free quotes from as many local heating engineers as you need.
Is a 40kW boiler too powerful or expensive?
Here are some less powerful combi boilers available right now for installation and these boilers are suited to small and medium-sized homes with up to 2 bathrooms, any more than 2 bathrooms and these will not be able to cope, but they are some of the best selling combi boilers on the market.
Combi boilers that work well are not connected to the gas network
Certain properties that are not connected to the gas network, such as off-grid homes, require an alternative heating system. For instance, instead of gas, a boiler that uses LPG (liquefied petroleum gas) can be used, which can be stored locally. Some powerful 40kW combi boilers are compatible with LPG.
Alternatively, oil can be used as a substitute for properties that are not connected to the gas network. There are various options available that can fulfill the same heating and hot-water requirements as a 40kW combi boiler.
If you are planning to install an oil boiler, you will require the services of an OFTEC-registered heating engineer.
