Boiler Replacement & New Boiler Guide for 2021

new boiler replacement

Boiler replacement guide for new gas boiler upgrades and installations

boiler replacement and new boiler guide

Boiler replacement or buying a brand new boiler is a purchase you make only every 10 to 15 years. It’s important that you find the right replacement boiler for a warm and happy home.

The cost of a new boiler varies significantly depending on the model and type of boiler that you require, which is dependent on the property that the gas boiler replacement that will be installed.

To help, we’ve produced this guide with everything you need to know. Use the contents above to find the specific questions you have in mind or read on for complete advice on replacing your boiler.

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This guide will give you everything you need to know about getting the best new boiler for your home.

Learn more below about how we determine the signs of old boilers, types of boiler replacements, new boiler quotes, boiler replacement deals, and more information on new boiler installation prices.

Should you replace your boiler with a new boiler?

With regular servicing, some old boiler models can withstand many years of use, but if you’re reading this, then it’s likely that you will need a new boiler and your boiler may need replacing soon.

Sometimes, you just need to bite the bullet as the repair bills can stack up pretty quickly, especially if you do not have a boiler cover plan.

Here are some indicators you need a replacement boiler:

  1. Your existing boiler is Beyond Economical Repair (BER). In these circumstances, it’s usually cheaper to get a new boiler than get it repaired. The brand-new boiler would also save you on your heating bills too.
  2. Frequent issues – requires you to have it serviced more than once a year or several call-outs mean it’s getting expensive and getting a replacement is the best option here.
  3. Energy efficiency – Your existing boiler may have poor energy efficiency, which usually means expensive gas bills. A change of boiler would be the best option here.
  4. Selling or renting your property – If you get a new boiler fitted it can increase the value of your home. If you rent it out, your tenants would love the energy savings on their bills . A replacement boiler usually adds value to your home.
  5. Your boiler leaks – If leaks are causing expensive call outs, then a replacement boiler may be the best option for you in the long run.
  6. Moving the system – If you would like to move your existing boiler to a new location, it’s usually better to just get a brand-new boiler. It would be less hassle and usually is the best option to upgrade your heating system.

If you’re experiencing any of these major issues, it may be time to say out with the old, and in with a new boiler.

In that case, it’s time for a replacement boiler, get a quote now below:

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How to get the best new boiler for your home

Deciding on the best type of new boiler is completely dependent on your home. For example, a small London flat with 1 bedroom would have a different replacement boiler than a 5 bedroom home in Mayfair.

Here, we have listed some of the main features to look out for when choosing a combi or gas boiler replacement.

The main things to factor into your decision are:

Hot water usage

1. Hot water usage:

Large families that use a lot of hot water will find a regular boiler more efficient. A home with fewer occupants will benefit from a combi boiler. 

2. Home size:

Because combi boilers don’t require hot water cylinders, we can install them in a home with less space. See our recommended replacement boiler size chart depending on the size of your home

Size of Home & Hot Water DemandCombi Boiler Output
1–3 bedrooms, 7–10 radiators, 1 bathroom20–29kW
3–4 bedrooms, 11–15 radiators, 1–2 bathrooms30–35kW
4+ bedrooms, 16–20 radiators, 2+ bathrooms36–60kW

3. Solar water heating compatibility:

If you’re using solar to power your hot water, it’s important to know that many combi boilers are less compatible and inefficient with this heating system. Contact us if you’re unsure.

Read more: Types of Boilers: Which are Best for Your Home?

Many old gas regular boilers and oil boilers are just boilers with hot water cylinders to live in the airing cupboard and cold water tanks to live in the loft.

When replacing regular boilers or system boilers, you should be able to keep the hot water cylinder to go with your new boiler installation.

Combi boilers are the most popular in the UK. Combi boilers, also known as ‘combination boilers’ are a 1 unit system that lives in a kitchen cupboard.

A combi boiler is brilliant unless you require a high demand for water at once to multiple taps. In this case, you would be better with a regular boiler.

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Replacing a specific type of boiler

Now we will discuss different options for a replacement boiler. One of the following types should match the boiler in your property. Take a quick look at our replacement boiler summary table before our in-depth guide.

Replacement Boiler TypeHome SizeBathrooms & ShowersRadiatorsOther Reasons To Buy
Combi Boilers1–4 BedroomsUp to 2 Bathrooms5–20 RadiatorsCompact & Easy To Install
System Boilers3+ Bedrooms2+ Bathrooms10+ RadiatorsHigh Hot Water Demand
Regular Boilers3+ Bedrooms2+ Bathrooms10+ RadiatorsLow Water Pressure

Gas boiler replacement

A new gas boiler replacement is our bread and butter here at Boiler Central.

We replace thousands of gas boilers throughout the UK each year, of which are all gas boiler replacements as we do not currently offer oil or electric boilers.

It’s paramount to get the best gas boiler for your home, and with Boiler Central, you can get the exact replacement options that are available for your home type online in seconds.

Below are some replacement boiler options and we go into more detail on the different types of new boiler options, one will surely be suitable for your home.

Regular gas boiler replacement

Heat-only boilers are conventional systems, also known as regular boilers.

These models store hot water in a cylinder and cold water in a storage tank.

new boiler replacement

A regular boiler produces hot water more efficiently than combi boilers and can supply multiple taps at once with water.

The circulation pump is housed as an external component, along with feed and expansion tanks. 

These typically feature an on and off switch. This means you can heat the water in the storage tank when you know you’ll be using it. You’ll conserve energy when it’s not in use. 


  • Conventional boilers work well with large households.
  • Large amounts of hot water can supply multiple taps at once.


  • Replacing a conventional boiler with a combi can be a complicated process.

Gas boiler replacement for a combi boiler

Combination boilers, also known as combi boilers, are the most popular type of home boiler systems registered in England.

Boiler replacement and new boilers

They provide a combination of instant hot water and efficient central heating.

When you request heated water, a sensor signals the boiler to burn fuel, either gas, electric, or oil. 


  • Gas combi boilers don’t require any external components, making it appear sleek and compact.
  • Hot water is available on demand without the use of cold water or a feed and expansion tank.
  • They are more affordable to install than regular models.


  • More internal moving parts means there are more potential malfunctions. These issues may be more expensive to fix than with a conventional boiler. 
  • Hot water from a combi boiler system can only support one user at a time. This makes combi boilers less ideal in a larger home. 

Get a boiler quote with an instant finance decision online – click here

New combi boiler: Why get one?

There are many reasons why you should get a new combi boiler. The first would be that according to the Energy Saving Trust, you can save £340 a year on your gas bills.

Just by getting a new combi boiler, you could pay for your replacement boiler in a matter of years. With the ever-increasing energy bills, getting a new combi boiler has never been easier.

If you need some help in choosing what the best combi boiler replacement is then we have guides on this, or alternatively, you can get a fixed price online – click here to do so.

A simple swap of a new combi boiler is really easy and usually takes 4-6 hours for a Gas Safe engineer to fit from start to finish.

However, if you are looking to replace a water tank with a combi boiler then you will have currently a system boiler, therefore you would need a gas boiler replacement system boiler. You don’t usually need to change the hot water tank unless it’s really old.

Read below on your options for changing a system boiler to a new combi boiler:

System gas boiler replacement

System boilers are known as closed vent boilers.

Upgrading boiler replacement

These are perfect if you prefer a heat-only boiler but would like less external components.

Like a combi boiler, these models have their external components built into the body of the heating system. 

System boilers contain a hot water cylinder, but the feed and expansion tanks are supplemented with an expansion vessel located in the new boiler.

This is where the circulation pump and the valves are housed. 


  • System boilers work well with large homes where heated water is needed for more than one task at a time.
  • They don’t require the space needed for a conventional new boiler.
  • System boilers are very efficient in areas with low water pressure.


  • They require space for the heated water cylinder.
  • Installation costs are higher than with basic combi systems.
  • They are less efficient than combi systems since they lose heat from stored water in the hot water cylinder.
  • One has to wait for it to heat up again after heated water has emptied from the cylinder. 

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Replacing a boiler: How much to upgrade?

Cost of upgrading a boiler

A boiler upgrade is a great investment for your UK home. Whether that’s a combi boiler, system or regular boiler they all have their place in certain home types.

We offer authorised and regulated payment options to make sure you can afford whatever new boiler you choose.

Based on the new boiler you’ve chosen, and our intake evaluation, replacement costs will vary.

To give you an idea, in the UK a conventional gas boiler replacement plus thermostatic radiator valves will typically cost around £2,300 before factoring in additional individual radiators.

Financing a new combi boiler replacement

Combi boilers cost significantly less than regular models because these models are less complex.

New boiler financing options

However, the price of your combi replacement will depend on the labour required to fit in the model of your choice.

New boiler financing options

If you’re overwhelmed at the cost of your new boiler, don’t fret. There are many financial conduct options available.

We offer access to a new boiler with 0% interest-free financing, interest-bearing credit, and monthly payment options regulated by the Financial Conduct Authority.

New gas boiler warranties

We use our vetted and trusted Gas Safe engineers to handle all of your boiler replacement needs, for safety, and your peace of mind.

replacement boilers

In our busier months, some of our old boiler replacements are fitted by our trusted subcontractors.

We assure you that all of our engineers will perform with the utmost safety and professionalism.

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Cheap boiler replacement

If you are looking for a cheap combi boiler then there are some good options on the market that you can choose from.

It must be said that in general, you will find that the cheaper new boilers are, the shorter the warranty will usually be. For example, you can pick some new boilers up for £1,499 but they may have a short 2 or 5-year warranty.

If you spend a little more than these cheap new boilers, then you can start to get longer warranties from 7-years to 10-years, from manufacturers like Worcester Bosch.

Getting the cheapest replacement boiler is not always the smartest idea. You may be better getting a more expensive boiler with a longer warranty but finance it over 10-years so it’s paid off in manageable chunks.

Boiler Central offer 1 to 10-year finance, so get a quote here to see your options. You can even see the monthly repayments and ensure that it’s cheap enough when you replace your boiler.

What are the cheapest new boiler models?

Below we round up some of the cheap new boilers that you can get your hands on if these are your desired price:

  • Vokera EasiHeat 25kW – These boilers are great workhorses for 1–3 bedroom homes – Price one up – click here
  • Alpha boilers – Fantastic replacements from 29kW power
  • Vaillant boilers – They have some cheap boiler options in their range

Many of the above new gas boiler options are cheap, in the region of £1,499 model and retailer dependent.

Boiler replacement deals & offers

There are not really many deals to be had with boiler replacements, but companies like Boiler Central offer some unbeatable deals such as up to a 12-year warranty on all Worcester Boilers and Viessmann boilers purchased online.

This deal is unheard of in the industry and were the pioneers to introduce this fantastic combi boiler replacement deal into the online market. Get a price below in seconds, choose your fuel type:

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Are boiler replacements the right option?

No one wants to waste money on their gas bills with a boiler that is draining money when it’s on. Plus, it’s not eco-friendly and getting an upgraded boiler can save you up to £340 per year on your bills.

Most homes have their heating on throughout the winter months, so it’s best to get full boiler replacements ready for the coming winter.

Boiler offers and deals

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New boiler offers UK

Everyone wants to get an offer on their new gas boiler, that’s why at Boiler Central we give you fixed prices online. They will not change even if we have to complete extra work on the day.

We have new boiler offers on every day of the year, with the lowest prices in the UK.

Whether you are looking for new combi boiler offers or deals; or getting that old back boiler replaced with a huge deal on a new system boiler, we can help.

There is a wide range of new boiler offers and deals at Boiler Central, check out our new boiler deals blog to find the most suitable replacement for your UK property.

New boilers for UK properties

We only install boilers in UK properties.

This gives us nationwide coverage so that you can have peace of mind that if you order a new boiler in the UK, we can fit it as quick as the next day.

To get a quote online now – Click here

How to get a new boiler

It couldn’t be simpler when getting a boiler replacement. Gone are the days where you have to call British Gas (who are around 3 times as much as us, seriously) who would send out a surveyor to your home.

Well, we say surveyor… They are salespeople, disguised as a surveyor.

Now you can order a boiler upgrade from anywhere in the world as long as you have an internet connection, from your phone, tablet or desktop computer.

Get a boiler quote with an instant finance decision online – click here

Why buy a new boiler?

If you have searched Google, something like “buy a new boiler” then you clearly are undecided on what boiler make or model you require.

With Boiler Central, you can choose your own installation date on our booking calendar as quick as next day and we make everything online.

It really never has been easier to buy a brand new boiler upgrade and we are dedicated to making it as easy as possible to purchase online. Choose your fuel below and get an online quote:

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Q What kind of fuel does your boiler use?

If you’re beginning to notice major issues coming from your old boilers such as high power bills, unusual smells, or leaking units, it’s time to consider a replacement boiler.

Using our online quotation system, answer 9 simple questions about your home and water usage to find the fuel and boiler that’s efficient for you.

Once we’ve received your information, we’ll act as a credit broker to help you finance your boiler replacement, if you require finance. You can also pay after installation by card, Paypal or even buy now and pay in 6 months.

We’ll provide a budget replacement boiler right through to mid and top-end boilers by answering just 9 simple questions.

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** 12-Year Warranty on selected Worcester Bosch & ViessmannGet a Quote Now >