Combi boiler replacement cost
According to prices submitted to WhatPrice by UK homeowners the cost of a new combi boiler including installation is £2,802 on average.
As a homeowner, the cost of a new boiler is never a welcome expense. That said, opting for a more energy efficient combi boiler can save you money in the long run.
Depending on the age of your existing boiler, buying a new combi boiler can also be necessary to ensure your property has an adequate supply of heating and hot water.
To help you price up a new combi boiler and installation fees, the WhatPrice team has put together the following guide.
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What is a combi boiler?
A combination boiler (combi boiler) provides both hot water and central heating from a single unit. This type of boiler conveniently offers water on demand without needing a separate hot water tank. Popular due to being energy efficient and space saving, combi boilers are available in a range of different sizes to cater to different properties.
Why choose a combi boiler?
When comparing the price of combi boilers, it can be useful to discover their advantages, especially if you are considering whether the cost is justified or not.
Combi boilers are ideal for those who appreciate:
- An energy efficient boiler
- Having heating and hot water on demand
- Choice between the size of boilers available
- Compact in size
- Easy to install (especially if replacing a like-for-like boiler)
So long as your needs are modest (i.e. you don’t need to run multiple showers at once) and your property has decent water pressure, combi boilers can offer an ideal solution.
In terms of running costs, gas combi boilers are also cheaper to run compared with electric boilers.
Compare combi boilers
A huge advantage of the modern combi boilers that are available in the UK is that there are some excellent options to choose from. This is in terms of reliable performance, energy efficiency and the overall reputation of the brand name.
Based on some of the combi boilers we’ve previously reviewed at WhatPrice, some of our top rated makes include Alpha, Baxi, Ideal, Worcester Bosch, Vaillant and Viessmann.
Longest warranty periods: Both the Worcester Bosch Greenstar 4000 (voted our best combi boiler) and Ideal Vogue Max are backed by an impressive 12 year warranty.
Best for larger homes with high hot water demands: The Vaillant EcoTec Plus is one of the more pricier boiler makes out there, though offers superior performance.
Best boiler for small homes or tight spaces: The Viessmann Vitodens 050-W is a highly regarded compact boiler and voted one of our top 10 best combi boilers.
Buying a new combi boiler on a budget: The Alpha E-Tec NX Combi Boiler and Ideal Vogue Max offer reliability but without the top price tags.
You may also like: Read more about finding the perfect boiler for your home on our guide of the top 10 combi boilers.
What size combi boiler should I choose?
In short, the size of the combi boiler you need will depend on the power that is required to heat your radiators and provide on-demand hot water for your property.
Generally speaking, the larger your property in terms of the number of bedrooms and radiators, the more powerful a boiler you will require.
How many radiators can a combi boiler run?
| Property type | Number of radiators | Boiler size |
|---|---|---|
| Apartment or house with up to 2 bedrooms | Up to 10 | 24kw-27kw |
| Apartment or house with 2-3 bedrooms | Up to 15 | 28kw-34kw |
| House with 4 bedrooms | Up to 28 | 35kw-42kw |
Combi boilers are extremely capable of keeping your radiators warm. Though, the boiler size you will need will very much depend on the total number of radiators in your home.
Typical research by the leading boiler installers has measured the capabilities of combi boilers for up to 28 radiators. This is reassuring as the average home in the UK only has around 10 radiators.
Before selecting a boiler size, your installer will also ask you to count the number of radiators in your property to ensure your new combi boiler will be compatible.
Combi boiler size guide
Most boiler makes are available in 3 different sizes.
Crucially, the ‘size’ of a boiler doesn’t refer to its physical height or width, but rather its power output in kilowatts (kW).
The typical size of a gas combi boiler is between 24kW to 42kW.
When you submit quotes for a combi boiler, the answers you give about your property size and usage needs will help determine what size boiler you need.
Why get a new combi installed?
Granted, no homeowner or landlord welcomes a combi boiler replacement cost. But given the importance of having heating and hot water in your property, the cost soon becomes justified especially when you learn just how energy efficient and reliable new combi boilers can be.
Ultimately, if your current boiler isn’t performing very efficiently or is subject to frequent breakdowns, then it will be costing you more to run. Older boilers can also be unreliable, meaning they may stop working at any time.
By upgrading your combi boiler now, you prevent the scenario where you are left without heating and hot water. Also, you can benefit from having the time to compare the costs involved without having to rush into a decision urgently because your old boiler has packed in.
Plus, if you plan on selling your property any time soon, a study by a major comparison website found that a new boiler can add up to 4% to the value of your home. In contrast, an old boiler can be off-putting to potential buyers and renters alike.
Looking for a new boiler?
Get free quotes and compare prices with our simple enquiry form today
What is involved in the installation of a combi boiler?
For straightforward combi boiler installations, it will usually take between 4-6 hours for a gas engineer to complete a like-for-like swap.
However, if you are switching from another boiler type such as a system boiler, it can take 1-2 days and involve more significant pipework changes.
Based on a typical like-for-like swap, your heating engineer will need to perform the following steps:
- Turn off the gas and electricity and drain the system down
- Remove the old boiler and current flue
- Fix a mounting bracket to the wall to secure the new boiler
- Connect the gas and water supply to the new boiler
- Install a new flue
- Use a power or chemical flush to clean the system
- Refill the system and bleed the radiators
- Set the boiler pressure and do safety checks
- Configure the settings on the boiler
- Show you how to change the settings on the boiler and complete any final paperwork
It’s good to note that the need to comply with current building regulations can impact the typical
combi boiler installation cost.
For instance, boiler flues have to be a certain distance away from your neighbour’s boundary. If your previous combi boiler was installed before these new regulations, then there may be extra costs involved in relocating the flue.
Since every boiler installation can look different, it’s good to be prepared for what might be required in your particular case.
How much could you save with an energy efficient combi boiler?
Something that can make new combi boiler prices far more attractive is understanding how much you might save by replacing your current boiler.
Our research has found that upgrading an inefficient boiler to a modern combination boiler can save 20%-35% on your energy bills, which works out to an average of £580 per year.
As you might expect, the total savings can vary. For example, if you also upgrade the energy efficiency of your home elsewhere with new windows and doors, then this can potentially increase the savings of a new combi boiler.
Choosing a reliable installer
Our research found the average combi boiler fitting cost to be £2,802. Considering the cost of combi boiler prices fitted is sensible, since every boiler will also need to be installed by a qualified engineer.
How to find a qualified plumbing and heating engineer near you:
- Local boiler installers
- National energy companies
- Online boiler replacement companies
As a minimum, only engineers who are on the Gas Safe Register can legally commission gas boilers in the UK.
Installers that are more experienced, including those with more industry accreditations (i.e. CIPHE or Trading Standards approved) are likely to charge more for their service.
However, opting for a well regarded plumbing and heating engineer can prove to be a smart investment, not least when it comes to peace of mind in terms of the quality of the installation.
Warranty, Service & Maintenance
When calculating the cost of a combi boiler replacement, it’s important to look beyond the boiler and installation costs. That’s because the cost of a boiler service or maintenance should also be factored in.
To ensure your boiler is covered under its warranty, the manufacturer will usually require your boiler to be serviced every 12 months.
It can be easier and cheaper to opt for an annual service package, either with the boiler manufacturer or through a gas and heating engineer. How these packages work is that you pay a certain amount per month to get cover for boiler servicing and breakdowns. Some packages also include the cost of a boiler replacement once your current boiler is at the end of its life.
In any case, regular maintenance is essential to ensure your boiler is both safe and efficient to use.
When looking at the boiler warranty, it is also good to note that some of the best boilers are those with longer warranty periods. Some providers also offer extended warranty options for an additional fee.
How to get accurate new boiler quotes
Every property has different needs, meaning when it comes to the cost of a new combi boiler, the price can vary significantly.
To find the best price combi boiler for your home, we recommend doing the following:
- Get multiple quotes from different installers
- Use our boiler installation cost calculator tool to estimate costs
- Input specific information about your property to get more accurate quotes
- Opt for local and trusted installers to avoid third party costs or being overcharged for delivery
- Take the time to think about your decision based on your budget and overall needs
In Summary: How much does a new combi boiler cost in the UK?
According to prices submitted to WhatPrice, the average prices for a combi boiler are as follows.
- Average cost of a new combi boiler: £1,990
- Average cost of a gas combi boiler installation: £812
- Cost of new combi boiler and fitting: £2,802
If you have boiler cover, the average cost of a combi boiler will be lower as you may only need to pay for installation costs. However, if you need to pay for both a boiler and the installation upfront, the price will typically be higher.
It is worth comparing installers (i.e. local vs national) as it is usually possible to find deals and incentives that can bring the costs down. For instance, if a gas engineer is able to purchase your new boiler at trade prices, then this can bring the overall costs of a boiler down with their installation included.
Looking for a new boiler?
Get free quotes and compare prices with our simple enquiry form today
Combi boiler cost FAQs
When pricing up the total combi boiler and installation cost, it’s likely you’ll have a few questions first. We’ve answered some of the most popular queries about the cost of a new combination boiler below.
Are gas combi boilers energy efficient?
Yes, modern gas combi boilers are incredibly energy efficient. Gas combi boilers installed today are required to meet an energy efficiency rating of 92%. Therefore, if you are looking to upgrade your boiler from a previous model, you should notice a huge improvement in energy efficiency.
Are combi boilers suitable for larger homes?
Combi boilers are suitable for larger homes up to a point.
In general, if the property has more than five bedrooms and two bathrooms, a system or standard boiler may be recommended instead of getting a new combi boiler fitted.
Can I have a combi boiler if I have multiple bathrooms?
Yes, it is possible to have a combi boiler installed if there is more than one bathroom in the property. However, you will likely need a larger boiler to be able to keep up with demand.
Rest assured that before getting a new combi boiler, you will be asked a series of questions to help determine the best boiler for your particular needs. Along with the number of bedrooms and radiators, a heating engineer will also ask about the number of bathrooms the property has.
How much is a combi boiler?
According to our research, the average cost of a new combi boiler is £1,990. The total new combi boiler cost will depend on the size of the boiler.
The cost of a new combi boiler and fitting averages £2,802. The exact price you will pay depends on the brand of boiler, the power of the boiler and the complexity of the installation.
How do combi boilers work?
Combi boilers take water from the mains and heat it as and when required. What’s particularly clever about a combi boiler is that the water needed to heat both your hot water and central heating is powered by one compact installation. A thermostat can control the temperature of both, and can also kick in automatically when the temperature falls below a certain level (i.e. in the winter when the temperature of the house is too cold). Overall, combi boilers are a very efficient system to have, especially if you upgrade to a modern energy efficiency model.
Can you have a power shower with a combi boiler?
The short answer is no, most power showers are not compatible with combi boilers. However, with most combi boilers producing around 12 litres of hot water per minute, this does produce a very decent flow rate for showers. Some examples of showers that are compatible with a combi boiler include mixer showers, digital showers or electric showers.
What size combi boiler do I need?
When getting combi boilers fitted, the size combi boiler you will need depends on three key factors. These include your property type, the number of bedrooms and the number of radiators.
Generally speaking, an apartment with 1-2 bedrooms and up to 10 radiators will need a 24kw-27kw boiler.
For an apartment or house with 2-3 bedrooms and up to 15 radiators, the ideal boiler size is 28kw-34kw.
Finally, a 35kw-42kw boiler is recommended for a house with at least 4 bedrooms, 2 showers and up to 28 radiators.
Do combi boilers need a water tank?
No. The beauty of a combi boiler is that they don’t need a water tank to work. Instead, combi boilers get their water supply directly from the mains.
If you have an existing water tank, you may want to think about getting this removed when factoring in your new combi boiler installation cost.
While optional, removing any redundant water tanks will free up space in your home. This is especially the case if you have a water tank in a bedroom, or a similar inconvenient spot where the space could be put to much better use.