Best New Combi Boiler Prices in the UK for 2023 (Buying Guide)

Want to know how to cut through all the chaff and ensure you get the best new combi boiler deals around? In this guide, that’s exactly what we are offering. We will tell you all the tricks of the trade, advise on the key information to look out for, and offer the top tips you need to know to get a great deal on a new combi boiler.

New Combi Boiler

Buying a new combination boiler is a daunting task as it’s a big outlay on something you probably don’t know very much about.

In this guide, we are going to walk you through all the things you need to know, the things to look out for, and the things to avoid. We are also going to share some top tips from our industry experts on how to ensure you definitely get the right new boiler deal for your property.

Whether you’re looking for a replacement oil boiler, a new combi boiler, or switching energy type, this guide has everything you need to know.

What Should Be Included In Your Home Boiler Deal

When you are seeking out a new home combi boiler, there is far more you need to be looking at than just the boiler itself. Boiler installation is a skilled and difficult job and doesn’t come cheap. Then there are all the various add-ons you need might need to install alongside the new boiler.

There are various things you need to do to your system to get a new combi boiler working to its full potential. Then there is perhaps the most important thing of all; the warranty.

So, before we go any further, let’s take a closer look at some of the things you need to be thinking about:

Itemised Quotes

You might ask a tradesperson for a quote and it comes back looking far cheaper than you expected. Oh, happy days, you might be thinking.

But be cautious. Just because a quote might look cheap, doesn’t mean it’s offering you good value for money. Make sure you get an itemised quote, so you can compare exactly what different installers are offering you.

One boiler installation quote will differ from another, so you need to make sure an affordable quote includes everything you need. You should look out for such things as:

  • Are Boiler filters included in the installation?
  • Is the brand of boiler good enough?
  • How long is the warranty?
  • What is the boiler’s KW output?
  • Are you using an accredited installer?
  • Does the quote include everything you need to get your full warranty?

Boiler Protection

Not every installer will quote including all the preventive measures you need to protect your expensive new boiler. Limescale (especially in hard water areas) and heating sludge are big problems and can void warranties and damage new boilers.

Most heating engineers worth their salt will offer the following whenever they install a new boiler:

  • Hot flush your heating system to remove loose heating sludge
  • Does the system with inhibitor
  • Fit a magnetic system filter (if needed)
  • Install a limescale filter if you live in a hard water areas

All of these things help to protect expensive boiler components, such as the heat exchanger and pump. A blockage can easily form if your boiler isn’t protected from heating sludge and limescale. Getting these problems fixed are not cheap and if you don’t fix them your boiler can end up being badly damaged.

A new pump could cost £250, and a heat exchanger replacement can be as much as £500! Make sure these preventative measures are included in your installation or you will end up paying more further down the line.

Brand & Warranty

There are plenty of inferior combi boiler boiler brands out there but if you want to get the best value for money, the unanimous advice of our experts is to stick with the established and reputable combi boiler brands.

Typically, that will add around £100-300 to the cost of your boiler and around 10% on the full cost of the install.

Longer warranties and better-quality products will invariably mean you boiler lasts longer too. Cheap brands are usually unreliable and the short warranties they come with certainly suggests the manufacturers know this too.

The small additional cost of buying a reputable branded boiler with a long warranty is well worth it for the long-term benefits.

We always recommend buying a boiler with a minimum of a 5-year warranty and always sticking to leading brands such as:

You should also be aware that not all warranties are clear cut. Often there are longer periods of warranty available if you jump through certain hoops.

These can include things like using approved tradespeople or official parts. For example, Ideal Boilers (Logic & Logic+) come with a long warranty but the heat exchanger comes with a 10-year warranty. That really delivers peace of mind because a replacement could cost up to £500.

We also recommend using an online installation company such as Compare Combi Boiler Quotes. They offer excellent boiler deals complete with a 10-year warranty. Their prices on Worcester Bosch appliances are among the very best around. You can use this form to get an on-screen boiler price from Compare Combi Boiler Quotes in less than 2 minutes.

KW Output

Smaller properties will typically need a 24kw boiler but as you get to bigger properties where there is high hot water demand, it might make sense to scale this up to 30kw.

The difference in price could be as little as £100-150. Therefore, if you’ve got two quotes that are approximately the same price, but one’s is for the equivalent higher KW boiler but the same model, you will be getting better value for money if you go for the higher kw option.

In the past, this was why most people didn’t buy boiler package deals online but relied on their engineerinstead. The engineer was the only person able to spec your property correctly and ensure that the boiler being fitted was powerful enough.

But that’s all changed now and sites like Compare Combi Boiler Quotes conduct a short online survey that enables them to judge exactly what size boiler you need and offer you the most competitive prices for your property.

Get multiple quotes

It’s standard consumer advice these days, but always serves repeating. If you are buying a new boiler you should always get a minimum of three quotes. There are lots of different options out there and they all want your business so why not seek out the best deal you can find?

The more itemised quotes you get, the easier it will be to determine which one’s the best, and not just based on price but the quality and range of things included in the price.

Types Of New Boiler Deals For Your Home

Should You Consider Pay On Completion New Boiler Deals?

A Pay on Completion deal is likely to be the cheapest way to finance a new boiler as you will be paying for the boiler, the parts, and the labour and absolutely nothing else.

Even if you have to take out a small affordable loan, it often makes sense to opt for a pay on completion deal, even over a 0% finance deal.

Large National Companies

There are plenty of national boiler installation companies like British Gas out there that advertise widely with what appear to be great deals on new boilers, offers on scrappage discounts and insurance policies.

As a customer, you need to be asking yourself who is paying for these adverts? The answer is you. A national installation company can charge anything from £600 – £1,200 more to install a new boiler than a local engineer will.

Regardless of what special deals they have on offer, these companies are almost always the most expensive way to get a new boiler. If you don’t believe us, go ahead and get a quote and compare it with the other options detailed below.

Local Installers

Local installers will be much cheaper than national ones on the whole and may even have special deals with local companies to get you good prices on boilers and parts.

It is well worth getting quotes from a couple of different local tradespeople as these independent traders can vary their prices quite considerably.

When considering a local quote, you also need to be sure what is included in the quote and what isn’t. For example, two different installers might offer the same price. But do they both include things like a magnetic system filter? Are they both a fixed price?

Online installers

Our advice is to put these quotes up against the best online boiler installers in the business too.

If you go to WARMZILLA’s website you can get a fixed price quote on a great boiler in less than two minutes without having to submit any personal details.

If you want to get a quality boiler like a Worcester Bosch at the best possible prices, we are pretty confident that WARMZILLA will offer the best prices you will find.

What Are The Benefits Of Buying Boilers On Finance?

If the price of a new boiler is too much for you to pay in one go and you don’t like the idea of a loan, a finance deal might be attractive.

It is often worth doing too. If you’ve got an old boiler, you could end up saving as much as £300 a year on energy bills, as well as avoiding expensive repair costs if you are out of warranty. This essentially means yournew boiler could actually pay for itself.

Boiler finance deals can vary from 0% APR to just above 20% APR. But, it’s not always as simple as choosing the lowest interest rate

Interest Free Finance Boiler Deals

As with a regular deal, if you are buying a boiler on finance, it is just as important (if not more so) that you get multiple itemised replacement quotes.

This is because you can still end up paying a lot more. For example, a company charging £3,000 for a new boiler installation that a local engineer would only charge £2,000 for, is always going to be happy to offer you 0% finance.

But, the cheaper option for you would be to go with the more competitive installer and get a short term loan instead.

Also, don’t be put off by companies offering a deal with a higher APR. Rather than just looking at the APR, consider the “total cost payable”, including the replacement AND the interest. Sometimes, even with a higher APR, this can still end up being less.

£17 Per Month Boiler Replacement Deals

Most new boiler finance deals will sit in the £15-20 a month range. £17 per month boiler replacement deals are particularly popular right now and that seems like a good price as it is comparable with your Netflix subscription.

But, like the 0% boiler finance deals, you’ll still need to get multiple quotes and look closely at the final price paid amount. You might find you are able to get a better APR deal and a lower monthly repayment if you can scrape together a small deposit.

Should You Get Boiler Finance?

Finance deals are fine and can even save you money on your energy bills and repair costs in the long run.

But don’t just leap into a finance deal without thinking first. Get multiple quotes and consider whether a loan or another means of payment might make more sense and end up costing you less.

Take a look at our full guide to getting new boilers on finance for more information.

Did You Know There’s A Free Boiler Replacement For Pensioners?

If you own your own property and meet the criteria, it is possible to get a free boiler with the government footing the bill. The easiest eligibility criteria is to be a pensioner.

ECO (Energy Company Obligation)

The Energy Company Obligation is the Government scheme in England, Scotland and Wales. To be eligible for a free boiler, you’ll need to be receiving Pension Guarantee Credit and be over 60.

Your property will need to use Gas, Oil or LPG and you will need to make an application online through the Government website.

Age Concern Free Boiler Replacement Scheme

If you live in Northern Ireland, the Age Concern Free Boiler Replacement Scheme is open to you.

You’ll be able to receive a grant of up to £1,000 if you have a household income lower than £40,000 and havea boiler that was installed more than 15 years ago.

Which New Boiler Deals Should You Choose For Your Home?

Obviously, if you do qualify for a free boiler, with no strings attached, that’s going to be the cheapest option for you and you should leap at the opportunity.

If you do have to pay for your new boiler yourself, a pay on completion deal will always be the cheapest and sometimes it is even worth getting a small loan to go about things this way.

Whatever method of payment you opt for, always be sure to get multiple quotes and compare different methods to ensure you are definitely making the right choice,

Always consider an online installer too as the likes of Compare Combi Boiler Quotes tend to be significantly cheaper than the rest of the market and offer great deals on warranty as well.

Vetting Your Boiler Installer

Once you have reached your decision, there is one more step for you to follow. Do some research into your installer to make sure they are Gas Safe Register. You can check that your engineer is qualified to fit your boiler on the register here.

We also usually recommend checking out any online reviews for the company you plan to use too. Take a look at sites like Google, Yell, Facebook, Yelp, and even Trust Pilot. They can tell you a great deal about the type of service you can expect.

Cost to buy and install new combi or system boilers

See the trade cost for combi & system boilers and how much local heating companies near you will charge for installing your new boiler (whether it is a like for like combi swap or installing a system boiler in a new location).

What are combi boilers?

Combi boilers (combination boilers) are compact small boilers which both heat water directly which comes out of your hot taps and also send hot central heating water to your radiators to heat your home.

How do combi boilers work?

To get your radiators hot the system water in your home’s radiators and pipes is circulated using a pump through the combi boiler’s main heat exchanger which is heated by a gas burner.

When you turn on a hot water tap or shower a flow sensor tells the combi boiler’s diverter valve to redirect the heated system water internally through a second ‘plate to plate’ heat exchanger which indirectly heats up mains water and in seconds sends the now hot mains water to your hot tap or shower.

No space needed for hot water cylinders or water tanks, low cost, range of out-puts to suit all properties, simple to install, maintain – all persuasive reasons why combi boilers are the number one choice when UK homeowners buy a new boiler.

What are system boilers and how do they work?

System boilers are a great solution for large family homes as they provide a constant supply of hot water for baths, showers and washing up. A system boiler works by filling a large, insulated storage cylinder with hot water so there is a constant supply of hot water ready to be used at any time.

How much do Worcester Bosch combi boilers cost?

  • Greenstar 2000 Combi boiler (25/30kw) – Suitable for one bathroom small to medium homes, fits between standard kitchen cabinets. Quietest in range, efficient and guarantee ranging from 5 – 6 years.
  • Greenstar 4000 Combi boiler (25/30kw) – Ideal for small to medium homes with one bathroom. Modern design, easy to use colour display, efficient, quiet and guarantee ranging from 7 – 8 years.
  • Greenstar Si Compact Combi boiler (25/30kw) – Suitable for small to medium homes with one bathroom, fits into a standard kitchen cupboard, easy to use controls and guarantee ranging from 7 – 8 years.
  • Greenstar CDi Compact combi boiler (28/32/36kw) – suitable for small, medium and large-sized properties with one or two bathrooms. Compact enough to fit into a standard kitchen cupboard but powerful enough for homes with more than one bathroom. Guarantee ranging from 7 – 8 years.
  • Greenstar 8000 Life Combi boiler (30/35/40/45/50kw) – most powerful wall hung combi boiler range with a modern design, wireless connectivity and guarantee ranging from 8 – 10 years.
  • Greenstar 8000 Style Combi boiler (30/35/40/45/50kw) – Top of the range, look like huge black or white wall hung iPhones, connected technology and power to comfortably heat large homes with two or more bathrooms. Guarantee ranging from 8 – 10 years.
Worcester Bosch Combi BoilersBoiler Cost
Greenstar 2000 25kw combi£600
Greenstar 2000 30kw combi£700
Greenstar 4000 25kw combi£820
Greenstar 4000 30kw combi£920
Greenstar 25Si Compact Combi£900
Greenstar 30Si Compact Combi£1,000
Greenstar 28CDi Compact Combi£800
Greenstar 30CDi Compact Combi£900
Greenstar 32CDi Compact Combi£1,050
Greenstar 8000 Life 30 Combi£1,040
Greenstar 8000 Life 35 Combi£1,150
Greenstar 8000 Life 40 Combi£1,300
Greenstar 8000 Life 45 Combi£1,550
Greenstar 8000 Life 50 Combi£1,800
Greenstar 8000 Style 30 Combi (Black or White)£1,100
Greenstar 8000 Style 30 Combi (Black or White)£1,200
Greenstar 8000 Style 30 Combi (Black or White)£1,350
Greenstar 8000 Style 30 Combi (Black or White)£1,600
Greenstar 8000 Style 30 Combi (Black or White)£1,850

How much do Worcester Bosch system boilers cost?

  • Greenstar 4000 System boiler (12/15/18/21/24kw) – Suitable for one bathroom small to medium homes. Modern design, quiet, easy to use colour display and guarantee ranging from 7 – 8 years.
  • Greenstar I System boiler (27/30kw) – Small but powerful, suitable for small, medium and large homes whilst fitting into a standard kitchen cupboard, easy to use controls and guarantee ranging from 7 – 8 years.
  • Greenstar 8000 Life System boiler (30/35kw) – most powerful wall hung system boiler range with a modern design, wireless connectivity and guarantee ranging from 8 – 10 years.
  • Greenstar 8000 Style System boiler (30/35kw) – Top of the range, look like huge black or white wall hung iPhones, connected technology and power to comfortably heat large homes with two or more bathrooms. Guarantee ranging from 8 – 10 years.
Worcester Bosch System BoilersBoiler Cost
Greenstar 4000 12kw System£800
Greenstar 4000 15kw System£850
Greenstar 4000 18kw System£880
Greenstar 4000 21kw System£890
Greenstar 4000 24kw System£950
Greenstar 27i System£940
Greenstar 30i System£980
Greenstar 8000 Life 30 System£1,060
Greenstar 8000 Life 35 System£1,180
Greenstar 8000 Style 30 System£1,150
Greenstar 8000 Style 35 System£1,250

How much do Vaillant combi boilers cost?

  • ecoFIT pure combi (25/30/35kw) – compact to fit in a cupboard so suitable for small homes. Efficient, quiet, smart controls and guarantee ranging from 2-10 years.
  • ecoTEC pro combi (24/28/30kw) – smart boiler for small to medium homes. Full range of thermostat controls (from analogue timers to ySMART app controlled) and 2-10 years guarantee.
  • ecoTEC plus combi (25/32/35/38kw) – high performance, precision control and efficiency suitable for any home and 5-10 years guarantee.
  • ecoTEC Green iQ combi (35/43kw) – best in range for efficiency and control, fully compatible with vSMART app, 85% recyclable and 5-10 years guarantee.
Vaillant Combi BoilersBoiler Cost
ecoFIT pure 825 combi£760
ecoFIT pure 830 combi£865
ecoFIT pure 835 combi£970
ecoTEC Pro 24 combi£850
ecoTEC Pro 28 combi£950
ecoTEC Pro 30 combi£1,000
ecoTEC Plus 825 combi£1,000
ecoTEC Plus 832 combi£1,100
ecoTEC Plus 835 combi£1,170
ecoTEC Plus 838 combi£1,260
ecoTEC Plus 938 combi£1,400
ecoTEC Green iQ 835 combi£1,250
ecoTEC Green iQ 843 combi£1,460

How much do Vaillant system boilers cost?

  • ecoFIT pure system (12/15/18/25/30kw) – compact to fit in a cupboard so suitable for small homes. Efficient, quiet, smart controls and 2-10 years guarantee.
  • ecoTEC plus system (12/15/18/24/30/37kw) – high performance, precision control and efficiency suitable for any home and 5-10 years guarantee.
  • ecoTEC Green iQ system (27kw) – best in range for efficiency and control, fully compatible with vSMART app, 85% recyclable and 5-10 years guarantee.
Vaillant System BoilersBoiler Cost
ecoFIT pure 612 system£730
ecoFIT pure 615 system£800
ecoFIT pure 618 system£865
ecoFIT pure 625 system£1,000
ecoFIT pure 630 system£1,060
ecoTEC plus 612 system£780
ecoTEC plus 615 system£840
ecoTEC plus 618 system£920
ecoTEC plus 624 system£1,050
ecoTEC plus 630 system£1,150
ecoTEC plus 637 system£1,270
ecoTEC Green iQ 627 system£1,150

Boiler installation steps

There is more to getting a new boiler than choosing a brand, boiler type and then getting a gas safe registered engineer to fit your new boiler to the wall.

  • Powerflush existing system using old boiler to clean out corrosion debris. The existing radiators and pipes will have corrosion debris in them which needs to be cleaned out so it doesn’t clog up the highly efficient low water content (ie very small holes) heat exchanger in your new boiler
  • Remove old boiler – say goodbye to your old faithful boiler (hanky handy for tears). Your old boiler may have been bigger, had pipes running in different directions and so some making good of cabinets or walls may be required.
  • New location or configuration will require adapting pipes, flue to suit new boiler. Different boilers have pipes coming and going from different positions and so some local alignment of pipes and flue may be required.
  • Fit new boiler. The big event….up goes the new shiny white box onto the frame and make all the connections (power supply, gas, mains water in, flow and return pipes, hot water out, flue, pressure relief pipe….anything else?).
  • Recommend extras to customer; corrosion debris filter, limescale inhibitor, smart controls, system corrosion inhibitor, bleed radiators, top up system pressure
  • Commission whole central heating system, explain to customer how to top up pressure, bleed radiators, set timer/thermostat/controls
  • Register new boiler for Gas Safe Register and manufacturer warranty


Extra costs to consider when getting a new boiler

Replace radiators£160-320
Add radiators£260-380
Powerflush radiators and pipes£250-800
Fit water tanks£135-180
Fit new central heating pipework£750-1,100
Install thermostat controls£120-250

Estimates for common heating engineer jobs;

Cost to replace a hot water immersion heater£275 
Cost to fit underfloor heating£250 
Cost to service a gas fire£150 
Cost to replace a vented hot water cylinder£330 
Cost to replace a central heating pump£95 
Cost to replace a heating programmer£180 
Cost to powerflush a central heating system£500 Visit
Cost to install heating oil storage tank£1250 
Cost to replace an oil boiler£1330 
New combi or system boiler installation – like for like replacement£500 
Cost to move and relocate a boiler£830 
Cost to install skirting board heating£990 
Cost to install an LPG boiler£1190 
Cost to install hydrogen boiler£1350 
Cost to install a gas fire£350 
Cost to install a chimney liner£575 
Cost to install biomass boiler£1430 
Cost to install a ground source heat pump£3750 
Cheap gas£110.00 per month
Cost to fix a boiler fault error code£85 
Cost to replace an unvented hot water cylinder, e.g., Megaflo£305 
Cost to fit thermostatic radiator valves (TRVs)£94 
Cost to fit smart heating controls£100 
Cost to fit a magnetic filter for boiler£113 
Cost to fit a heated towel rail£75 
Cost to fit a radiator£80 
Cost to install a gas cooker or hob£190 
Boiler service cost£90 
Boiler repair costs (e.g. pump, diverter valve or heat exchanger)£333 
Cost to install an air source heat pump£556 
Replacement of a vented system£580


In this guide, we have offered a range of tips that should help you to get the best new boiler deal around.

The keys rules are to consider your financial options carefully, always get multiple quotes, and don’t overlook online installers like Compare Combi Boiler Quotes as they can often undercut even local traders.

We will keep this guide regularly updated with all the latest advice and guidance. If you have any good tips we have missed or stories to share, you can always contribute too using the comment box below.

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