New gas boilers from £1,790 fitted
Fixed prices online in 20 seconds. Next-day fitting for most like-for-like swaps if you order by 3pm.
up to 14 years depending on model
Guarantee, registered for you
Next day
Like-for-like swaps if you order before 3pm (subject to slot and stock)
Gas Safe
Registered engineers
Fixed prices
The price you accept is the price you pay for the quoted scope
Get an online fixed price in 20 seconds
We supply and fit mains gas boilers, from £1,790 fitted.
For this month’s fitted prices by type and brand, see our boiler prices guide.
When should you replace your boiler?
With regular servicing, some models can withstand many years of use. However, there are some circumstances where the overall cost of repairs determines that a new boiler installation is a must. Here are some signs to look out for:
Rising energy bills
Your heating bills are suddenly more expensive with no explanation — a sign your boiler is losing efficiency.
Frequent breakdowns
Frequent issues require you to have it serviced more than once a year — repairs are costing more than a replacement.
Unusual noises
Your boiler and radiators are making unusual banging, whistling or gurgling noises — a sign of internal problems.
Strange smells
Your boiler smells sulphurous when it’s on — this could indicate a dangerous gas leak and needs urgent attention.
Leaks
Your boiler is leaking water — this can cause serious damage to your home and means the boiler needs replacing.
Old age
Your boiler is over 10-15 years old — modern A-rated boilers can save you money on energy bills.
Should you replace your boiler?
Use our scoring table to help you decide.
Scroll horizontally to view all columns.
| Question | YES | NO |
|---|---|---|
| Have you repaired your boiler twice or more in 1 year? | 10 | 0 |
| Do you want to remove a hot water tank? | 10 | 0 |
| Do you have an inefficient back boiler? | 10 | 0 |
| Is your boiler over 7 years old? | 5 | 0 |
| Is your boiler costing you more in energy bills? | 5 | 0 |
| Is there potential for your boiler to stop working? | 5 | 0 |
| Is your boiler out of warranty? | 5 | 0 |
| Do you think your boiler isn’t working properly? | 5 | 0 |
- 0 – No, your boiler is probably fine
- 5+ – Yes, worth considering a replacement
- 10+ – Definitely yes, replace as soon as possible!
What type of new boiler should you choose?
Combi Boiler
Combination boilers are the most popular type in the UK. They provide instant hot water and efficient central heating without requiring separate tanks or cylinders. Perfect for small to medium homes.
Pros: instant hot water, compact design, lower install cost, no tank needed.
Cons: one user at a time, less ideal for large homes, more internal parts.
System Boiler
System boilers work within a closed system using a hot water cylinder. Perfect for larger homes with multiple bathrooms where high hot water demand is needed simultaneously.
Pros: great for large homes, multiple bathrooms, works in low pressure, no loft tank needed.
Cons: needs cylinder space, higher install cost, wait to reheat.
Regular / Heat-Only Boiler
Also known as conventional boilers, these store hot water in a cylinder or storage tank. They produce hot water very efficiently and work well with large households with high demand.
Pros: high hot water output, multiple taps at once, works well in large homes.
Cons: needs cylinder & tank, hot water can run out, complex installation.
Not sure whether you need a combi or a system boiler? See system boiler vs combi boiler. Compare in more detail: our combi boilers and system boilers pages.
What size boiler do I need?
Scroll horizontally to view all columns.
| Home size & hot water demand | Combi boiler output | Recommended type |
|---|---|---|
| 1–3 bedrooms, 7–10 radiators, 1 bathroom | 20–29kW | Combi Boiler |
| 3–4 bedrooms, 11–15 radiators, 1–2 bathrooms | 30–35kW | Combi or System |
| 4+ bedrooms, 16–20 radiators, 2+ bathrooms | 36–60kW | System or Regular |
How much does a boiler replacement cost?
With Boiler Central, a new mains-gas boiler is offered from £1,790 supplied and fitted. Exact prices vary by home and model. In one example quote for a like-for-like combi boiler replacement in a 3-bed semi (checked 6 November 2026), fitted prices started at £1,928.99. You see the fixed price for your home in the online quote before you pay.
For wider ranges see the new boiler cost guide. On a budget? Read our cheap boiler installation page. Want to see how the online process works? See buy a boiler online.
For how the fitting works, including timings and what’s included, see new boiler installation and gas boiler replacement.
Boiler brands we supply and fit
We supply and fit mains-gas boilers from Worcester Bosch, Viessmann, Alpha and Ideal. Every fitted boiler comes with a guarantee of up to 14 years depending on model, registered for you.
Worcester Bosch
British-built Greenstar range
Viessmann
German-engineered Vitodens range
Alpha
Great-value combi and system options
Replacing a Vaillant or Baxi? We keep reviews for brands people already have — see the Vaillant, Ideal and Baxi guides — but Boilercentral.com fits Worcester Bosch, Viessmann, Alpha and Ideal only. Comparing installers? See Boilercentral.com vs BOXT, Heatable and iHeat or the British Gas boiler quote comparison.
Frequently Asked Questions
Are boiler replacements the right option?
Having an inefficient boiler can lead to high gas bills and negatively impact the environment. Upgrading your boiler can save you money on energy bills.
It’s best to replace your boiler before the winter months, as most homes have their heating on during this time. If you’re concerned about energy costs, consider investing in a smart thermostat to further reduce gas and electricity usage.
How easy is getting a new boiler?
It couldn’t be simpler. Gone are the days of waiting for a surveyor to visit your home. Now, you can order a boiler upgrade from anywhere in the world — from your phone, tablet, or desktop computer. Get a boiler quote online in just 20 seconds.
How long does it take to replace a combi boiler?
A simple swap from an old combi boiler to a new combi boiler is straightforward and usually takes 4–6 hours for a Gas Safe engineer to fit.
If you want to replace a system boiler with a combi boiler, this can take longer due to the extra work disposing of the old water tank. Back boiler to combi conversions typically take 2 days.
Is it worth replacing a 20 year old boiler?
Yes — older boilers such as back boilers are significantly less efficient compared to newer ones, with efficiency dropping to 50-60% after 20 years. A modern A-rated boiler operates at over 90% efficiency.
It’s recommended to consult with a Gas Safe engineer to determine if replacement is necessary, but in most cases it absolutely is worth it for the energy savings alone.
How much does a new boiler cost fitted in the UK?
With Boiler Central, a new mains-gas boiler is offered from £1,790 supplied and fitted. Exact prices vary by home and model. In one example quote for a like-for-like combi boiler replacement in a 3-bed semi (checked 6 November 2026), fitted prices started at £1,928.99. You see the fixed price for your home in the online quote before you pay. See our new boiler cost guide for more prices and examples.
What is included with a replacement boiler installation?
Boiler Central fixed fitted prices typically include the new gas boiler, removal of your old boiler, fitting by a Gas Safe registered engineer, a chemical flush with inhibitor, a magnetic filter, a wireless thermostat, and manufacturer guarantee registration. Your quote shows the guarantee for each boiler. Major extras such as moving the boiler or converting from a system, regular or back boiler appear in your quote before you pay. Confirm the full inclusion list on your quote.
Before installation:
- We assess your heating and hot water demands
- We select the best size boiler for your home
- You book an installation date
During installation:
- We remove your old boiler
- We run necessary gas, water and electricity lines
- We clean your central heating system
- We install and connect the new boiler
After installation:
- We commission the boiler to ensure it’s working correctly
- We set up the controls and thermostat
- We register your Gas Safe installation and manufacturer warranty
Can I get a fixed boiler price online and next-day fitting?
Yes. Complete the online quote using your answers about the home and boiler, then upload photos of your boiler and pipework after you order. Order by 3pm and, where your job, stock and postcode allow, like-for-like swaps can often be fitted the next day. Conversions commonly take around two days. Other system or non-like-for-like dates depend on job scope — use the first real date in your quote calendar. See next-day boiler installation and how buying online works.
What to do next to get fast boiler replacement in 24 hours?
Using Boilercentral.com’s online quotation system, answer 9 simple questions about your home and water usage to find the fuel and boiler that’s right for you.
Once we’ve received your information, we’ll provide a list of boilers we can install — from budget options right through to mid and top-end models. Choose the right one for your budget and we can be there as soon as tomorrow! Read how our next day boiler installation works.
Before you choose, our guide to what to consider when buying a boiler explains the key decisions, and how to buy a boiler online covers what to check before ordering. If you are replacing an older system, read our full guide to boiler replacement and new boilers.
Get a fixed price new boiler in 20 seconds
Next-day installation for most like-for-like swaps if you order by 3pm, subject to slot, stock and postcode. Fixed online prices from £1,790, with no salesperson visit needed to see your price.