Need a new gas combi and a clear installed price — without a sales call? Start the online quote, see fixed prices for boilers that suit your answers, then choose and book. Boiler Central supplies and fits mains-gas combis from £1,790. More on new boiler installation.
For most like-for-like combi swaps, next-day installation is available if you order by 3pm, there’s a free slot at your postcode and the boiler is in stock. We fit 7 days a week. Conversions take longer.
You see the installed price before you pay. After you order, upload photos of your boiler and pipework so the Gas Safe engineer turns up prepared.
How much does a combi boiler cost?
Combi boiler installation cost with Boiler Central starts from £1,790 for a mains-gas combi supplied and fitted. Exact prices vary by home and model. We fit Worcester Bosch, Viessmann, Alpha and Ideal only. You see a fixed online price from your answers before you pay.
A like-for-like combi swap is usually the cheapest path. Our quote shows one fixed price for your home and the boiler you pick.
Want the wider cost picture across boiler types? See the new boiler cost guide.
See this month’s combi boiler prices from our online quote.
What’s included in the fixed price
Every Boiler Central combi price is for supply and fit. Your quote confirms the full list for your job. As standard that covers:
- Your new gas combi, fitted by a Gas Safe registered engineer
- Removal of your old boiler
- Chemical flush, inhibitor and magnetic filter
- Wireless thermostat
- Commissioning and testing
- Gas Safe notification and manufacturer guarantee registration (your quote shows the guarantee for each boiler; up to 14 years depending on the model)
What’s not included as standard: major relocation of the boiler, large flue or pipework changes, and conversion extras when you move from a system, regular or back boiler. The quote shows any extras before you pay.
Combi swap vs conversion cost
A like-for-like combi-to-combi swap is usually the cheapest and fastest job. Converting from a system or regular boiler or a back boiler costs more and takes longer (usually around two days), so it is not next-day. Your booking calendar shows the first real date before you pay.
Is a combi boiler right for your home?
A combi (combination) boiler heats your radiators and gives hot water from the mains in one wall-hung unit — no hot-water cylinder or loft tank. It’s the usual choice for flats and small to medium UK homes.
A combi is usually right if you:
- Have about one bathroom (or light use of a second)
- Don’t often need two showers at full flow at the same time
- Want to free up airing-cupboard or loft space
- Prefer a simpler, lower install cost than a system boiler
Choose a system boiler instead if you:
- Regularly run two or more bathrooms at once
- Have a larger household with heavy morning hot-water demand
- Already have (or need) a hot water cylinder
Honest bottom line: a bigger combi doesn’t fix simultaneous showers the way a cylinder does. If that’s your routine, a system setup is the better buy. Read system vs combi or what is a combi boiler if you’re still deciding. The quote sizes the boiler for your answers — don’t oversize “just in case”.
What size combi do you need?
Scroll horizontally to view all columns.
| Home & hot water demand | Typical combi output |
|---|---|
| 1–3 bedrooms, ~7–10 radiators, 1 bathroom | About 20–29kW |
| 3–4 bedrooms, ~11–15 radiators, 1–2 bathrooms | About 30–35kW |
| Larger home / higher simultaneous demand | Often better as a system boiler |
These are guides only. Your online quote recommends outputs that fit your home; a Gas Safe engineer confirms on the day.
Combi boilers we supply and fit
We supply and fit mains-gas combis 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 combis — a strong all-round choice for most homes. The Greenstar 4000 (25kW and 30kW) is A-rated at 94% ErP space-heating efficiency, with a colour display and compact cupboard fit. The Greenstar 2000 is the quieter, more affordable Worcester entry point for smaller homes. More detail: Worcester Bosch prices & reviews.
Viessmann
German-engineered Vitodens combis with a stainless-steel heat exchanger. The Vitodens 050-W is a popular mid-range pick; the Vitodens 100-W is the step-up all-rounder when you want the higher-spec Vitodens combi. See Viessmann prices & reviews.
Alpha
Great-value combis for smaller and mid-size homes. See the Alpha E-Tec review and browse Alpha boilers. Exact models and fitted prices appear in your quote.
Searching for Vaillant, Baxi or Glow-worm? We keep reviews and guides for brands people already have — useful when you’re replacing one — but Boiler Central fits Worcester Bosch, Viessmann, Alpha and Ideal. Your quote shows the models we can install. For a wider shortlist, see best combi boilers UK.
How getting a combi with Boiler Central works
- Answer a few questions about your home and current boiler.
- See fixed prices for the gas combis that suit your answers.
- Choose your boiler and complete your online order — pick a date and finish the quote/order steps on screen.
- Upload photos of your boiler, flue and pipework.
- We fit it — a local Gas Safe engineer removes the old boiler, fits the new one, tests it and shows you the controls. A straight combi swap usually takes 4 to 6 hours.
No salesperson. The price you accept is the price you pay for that job scope.
Next-day combi installation
For most like-for-like combi swaps, order by 3pm and — if there’s a free slot at your postcode and the boiler is in stock — we can fit tomorrow. We work 7 days a week, weekends included.
Next-day isn’t available when:
- You order after 3pm (then the earliest is the day after)
- There’s no engineer slot near your postcode
- Stock is short (the quote calendar shows a later date)
- The job is a conversion (system/regular/back boiler → combi) — those usually take around 2 days
You’ll always see your first real date before you pay. Full rules: next-day boiler installation.
Combi boiler FAQs
How much does combi boiler installation cost in the UK?
With Boiler Central, gas combi boiler installation starts from £1,790 supplied and fitted. Exact prices vary by your home and the Worcester Bosch, Viessmann, Alpha or Ideal model you choose. You see a fixed online price before you pay.
What’s included in a Boiler Central combi installation price?
As standard: the new gas combi, Gas Safe fitting, removal of your old boiler, a chemical flush with inhibitor, a magnetic filter, a wireless thermostat, commissioning, Gas Safe notification and manufacturer guarantee registration. Guarantees are up to 14 years depending on the model. Your quote shows the exact list and years for your job.
Is a like-for-like combi swap cheaper than a conversion?
Yes. A like-for-like combi-to-combi swap is usually the cheapest and fastest option. Converting from a system, regular or back boiler costs more because of extra pipework and labour, and usually takes around two days, so it is not next-day.
How long does a combi installation take?
A straight like-for-like combi swap usually takes 4 to 6 hours. For eligible swaps, order by 3pm and, if stock and a slot are free for your postcode, fitting can often be the next day. Conversions usually take around two days. Your quote calendar shows real dates.
Do I need a survey to get a fixed combi price?
No. There’s no home survey. Answer a few questions online to see your fixed price, then upload photos of your boiler and pipework after you order.
Can two showers run at once on a combi?
A standard combi will struggle to keep full flow and temperature on two showers at once. Higher-output models cope better with light overlap, but for regular simultaneous use a system boiler with a cylinder is the more reliable choice.
What guarantee do I get?
We register the manufacturer guarantee for you. Guarantees are up to 14 years depending on the model. Your quote shows the exact years for each boiler. Keep it valid with an annual Gas Safe service.
What if I’m converting from a system, regular or back boiler?
Conversions cost more than a like-for-like swap and usually take around two days, so they are not next-day. See changing to a combi boiler and back boiler conversion. Your quote still shows a fixed price and first available date before you pay.
Ready for a fixed combi price?
Start the quote, see fitted prices for Worcester Bosch, Viessmann, Alpha and Ideal combis, and book a Gas Safe install — next day for many like-for-like swaps if you order by 3pm and a slot is free.
Still researching? Browse new boilers or the new boiler cost guide.