If your boiler is old, unreliable or inefficient, replacing it can feel urgent – but getting a clear answer to “how much does a new boiler cost?” is surprisingly hard.
Installers quote in different ways, headline prices often exclude important extras, and it’s easy to overpay if you don’t know what’s driving the number.
This guide lays out typical new boiler costs in the UK for 2025, how they break down by boiler type, and which factors really move your quote up or down.
- Average boiler replacement costs by type (combi, system, regular)
- What’s usually included – and what’s extra
- How property size, complexity and location affect price
- Where grants and finance fit in
If you already have your EPC to hand and want to know how a new boiler affects your rating, see Does a New Boiler Improve Your EPC Rating?. For EPC-wide upgrades, start with 27 Ways to Improve Your EPC Rating.
1. Average new boiler costs in 2025 (at a glance)
Every home is different, but typical all‑in installation ranges (boiler + standard fitting) are:
- Combi boiler replacement (combi → combi): often around £2,000–£3,000+
- System boiler replacement (like‑for‑like): often around £2,500–£3,500+
- Regular/heat‑only boiler replacement: often around £2,500–£4,000+ depending on cylinder and system upgrades
Moving from one boiler type to another (e.g. regular + cylinder → combi) or relocating the boiler can push costs higher due to extra pipework, flue changes and making good.
Use these ranges as a sense‑check – then get fixed, itemised quotes so you know exactly what you’re paying for.
2. Combi boiler costs
Combi boilers are the most common option in UK homes, especially smaller properties and flats. They provide heating and hot water from a single unit with no separate hot water cylinder.
Typical combi replacement scenarios
-
Combi → combi (same location)
- Generally the simplest and cheapest scenario.
- Typical all‑in cost: £2,000–£2,800+ depending on brand and output.
-
Combi → combi (new location)
- Requires extra pipework, flue routing and making good.
- Costs more; allow £2,300–£3,200+ in many cases.
Factors that increase combi costs:
- Moving from a small to a higher output combi for more hot water.
- Premium brand or extended warranty packages.
- Difficult flue runs or condensate routing.
Combi boilers work well in:
- Flats and smaller homes with one bathroom.
- Properties where you want to free up space by removing the cylinder.
3. System boiler costs
System boilers heat water for both central heating and a separate hot water cylinder. They’re common in larger homes and properties with higher hot water demand (e.g. multiple bathrooms).
Typical system boiler costs
- Like‑for‑like system boiler swap: often £2,500–£3,500+
- Upgrading the cylinder at the same time (e.g. to an unvented unit) can add £500–£1,000+.
When a system boiler makes sense:
- Larger homes with high hot water usage.
- Properties where simultaneous showers/baths are common.
Expect higher materials cost vs a simple combi swap – but system setups can provide more comfortable hot water performance in the right properties.
4. Regular / conventional boiler costs
Regular (also called heat‑only) boilers work with a separate hot water cylinder and cold water tank, often in the loft. They are common in older homes and rural properties.
Typical regular boiler scenarios
-
Regular → regular (same system)
- Boiler only, retaining existing tank and cylinder (condition permitting).
- Typical cost: £2,500–£3,500+.
-
Regular → combi
- More complex conversion; tanks removed, pipework changed.
- Typical range: often £3,000–£4,000+, depending on complexity, making good and any extras.
Conversions can be worthwhile where you want to:
- Free up loft and airing cupboard space.
- Simplify the system and reduce future maintenance.
However, in large or multi‑bathroom homes, staying with a system/regular + cylinder setup may still be the best option.
5. Boiler installation costs explained
Boiler quotes usually roll labour and materials into one number, but under the surface you’re paying for:
- Installer labour: survey, fitting, testing, commissioning and paperwork.
- Boiler unit and flue kit: core hardware from the manufacturer.
- Controls: thermostats, programmers, smart controls or TRVs if included.
- System cleaning: powerflush or chemical flush, filter installation.
- Ancillaries: pipework, fittings, valves, brackets, wiring.
- Certification: Gas Safe registration, building control notification.
Cheaper quotes sometimes omit key items (e.g. system cleaning or decent controls). When comparing:
- Ask what’s included and excluded.
- Check warranty length and who handles callouts.
- Ensure the installer is Gas Safe registered for gas systems.
6. What affects boiler cost most?
Several factors significantly influence your final price:
Property size and heat demand
- Larger homes need higher output boilers and potentially larger radiators.
- Bigger systems take longer to clean and balance.
System complexity and changes
- Like‑for‑like swaps are cheaper than type conversions or relocations.
- Adding or upgrading cylinders, zoning or underfloor heating adds cost.
Boiler brand and warranty
- Premium brands cost more but may offer longer guarantees and better support.
- Extended warranties can be worth it, especially for rentals.
Location and access
- Labour rates vary by region.
- Difficult access (e.g. high flues, tight cupboards, flats without lifts) can add time and cost.
Regulatory requirements
- Flueing, condensate disposal and ventilation must all meet current standards; upgrades here can add to the bill.
7. Does a new boiler improve your EPC rating?
Often, yes – particularly if you’re replacing an old, non‑condensing or G‑rated boiler.
- Modern A‑rated condensing boilers are much more efficient, so more of your fuel becomes usable heat.
- In many cases, this leads to a higher EPC score, especially when combined with improved controls.
The exact impact depends on:
- Your starting rating and heating type.
- What other fabric measures (insulation, glazing) you have in place.
For a full breakdown, including when a boiler upgrade should come before or after insulation, see Does a New Boiler Improve Your EPC Rating?. For band‑specific improvement paths, see:
8. Boiler grants and funding in 2025
Depending on your circumstances, you may be eligible for support with heating upgrades:
- ECO4 and related schemes – focused on low-income or vulnerable households in poorly rated homes.
- Boiler Upgrade Scheme – primarily for heat pumps, but relevant when deciding between a boiler and low‑carbon option.
- Local authority schemes – area‑based programmes that may include boiler or whole‑house upgrades.
For a detailed look at free or subsidised options, including eligibility and application steps, read Boiler Grants UK 2025: Free & Subsidised Schemes.
For broader home‑upgrade funding (insulation, heat pumps, solar), see Home Energy Grants UK 2025: Complete Guide to Funding (/insights/home-energy-grants-uk).
9. How to get the best boiler price
To avoid overpaying while still getting a quality job:
- Get at least two to three fixed, written quotes.
- Make sure each quote includes:
- Boiler model and output.
- What’s included (controls, filter, flush, warranties).
- Any additional works (pipework, flue, making good).
- Compare like for like – a slightly higher quote with better warranty and controls may be better value.
- Consider timing: off‑peak seasons or shoulder periods can sometimes mean more availability.
Online quote tools and specialist partners can help you benchmark prices and avoid surprises.
10. When to replace vs repair your boiler
Replacement isn’t always the right move. Consider:
When repair might make sense
- The boiler is relatively new and still in warranty.
- The fault is minor and cheap to fix.
- You’re planning to move soon, and EPC isn’t a priority.
When replacement is often better
- Boiler is 10–15+ years old and out of warranty.
- Frequent breakdowns or expensive parts needed.
- You’re planning to keep the property long term and want lower bills and better EPC performance.
- You’re a landlord needing to protect against tighter EPC rules – see EPC Rules for Landlords in 2025–2030.
11. Boiler vs heat pump: which is right for you?
With rising interest in low‑carbon heating, many homeowners are weighing new boiler vs air source heat pump.
High‑level trade‑offs:
- Boilers:
- Lower upfront cost.
- Familiar technology.
- Best suited to gas‑connected homes where deep fabric upgrades aren’t yet in place.
- Heat pumps:
- Higher upfront cost, but grants available.
- Much lower carbon emissions when run on a decarbonising grid.
- Work best in well‑insulated homes with suitable radiators or underfloor heating.
For a detailed comparison of upfront costs, running costs and grants, see Boiler vs Heat Pump: Cost Comparison and Air Source Heat Pump Costs UK.
12. FAQs
What is the average cost of a new boiler in the UK?
For a straightforward combi‑to‑combi replacement, many households pay in the region of £2,000–£3,000 including installation. System and regular boiler setups can cost more, especially if cylinders or locations are changed.
Is a more expensive boiler brand worth it?
Often, you’re paying for reliability, support and warranty length. For many homes, a mid‑range boiler with a strong warranty is a good balance. Premium brands can make sense if you’re planning to stay long term or want maximum peace of mind.
How much extra does a boiler conversion cost?
Converting from regular/system to combi, or moving the boiler, typically adds several hundred pounds (or more) compared with a like‑for‑like swap due to extra pipework, flue changes and making good.
Will a new boiler reduce my energy bills?
If you’re replacing a very old or non‑condensing boiler, a modern condensing model can significantly cut fuel use, especially when paired with good controls. The exact saving depends on your property, usage and gas prices.
What should I do next?
- Check your EPC and property recommendations using our EPC checker.
- Read Does a New Boiler Improve Your EPC Rating? to understand EPC impact.
- Use this guide to benchmark fair price ranges.
- Get a small shortlist of fixed, itemised quotes and compare warranty, scope and reputation – then schedule the installation at a time that minimises disruption.