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Get a Fixed-Price New Boiler Quote Online: How It Works & What to Expect
Online boiler installers now give you a fixed, all-in price in about 90 seconds — no home visit needed. This neutral guide explains how that works, what should be included, when a "fixed" price can still change, and how to compare an online quote against a local Gas Safe engineer like-for-like.
Quick answer
A fixed-price online boiler quote is an instant, all-inclusive price you get by answering questions about your home — typically the boiler, Gas Safe installation, flue kit, filter, controls, a system cleanse, commissioning and the manufacturer guarantee, with installation often available the next working day. Indicative 2026 UK prices for a combi swap run roughly £1,800–£3,500, with a median quote around £2,300 (based on a sample of online quotes; figures vary by provider).
The price is genuinely fixed provided your home matches what you declared. Non-standard flues, moving the boiler, a system upgrade or hidden problems found on the day can trigger a revised price. We are a boiler-cover comparison site, not an installer — this is general information, not personalised financial or gas-safety advice. Always confirm any quote and its inclusions on the provider's own page.
1. What is a fixed-price boiler quote (and how it differs from an estimate)?
A fixed-price quote is a firm, all-in figure for supplying and installing your new boiler. Unlike an estimate, it shouldn't drift upward once work starts — assuming your property matches what you told the installer.
An estimate is an educated guess that can change as the job unfolds. A fixed quote is a commitment to a number, with the small print spelling out the few conditions that can override it.
Online installers can offer fixed prices because they standardise everything: a set list of compatible boilers, a fixed parts bundle and a defined labour scope. That standardisation is what makes an instant on-screen price possible.
The key point: "Fixed" means fixed for a standard installation that matches your answers. It is not the same as a full survey. If your home differs from what you declared, the price can legitimately be revised — so the accuracy of your answers is everything.
2. How getting a boiler quote online works — step by step
Most online installers (for example BOXT, Heatable, Boiler Central, WarmZilla and iHeat) use a near-identical flow. You never need a person in your home for a standard swap.
- Answer questions about your home — current boiler type, number of bedrooms and bathrooms, how many radiators, fuel type and where the boiler and flue sit. This typically takes a minute or two.
- Get matched to compatible boilers — the tool filters to models that suit your home, often across brands like Worcester Bosch, Vaillant, Baxi and Navien (the exact brand line-up varies by installer).
- See an instant fixed price on screen — usually a few options at different price and guarantee levels.
- Upload photos (or do a short video survey) — of the boiler, flue, gas meter and pipework. This replaces the traditional home survey for most swaps and is how the installer confirms the job is "standard".
- Book the installation — often as soon as the next working day if you order before a cut-off (some installers, such as BOXT, use a 3pm cut-off; check each provider).
If you're unsure which boiler type suits you, read combi vs system vs regular boilers and what size boiler you need before you start, so your answers are right first time.
3. What's included in a fixed-price quote?
A good fixed-price quote is genuinely all-in. Inclusions vary by installer, so check each one rather than assuming. A typical bundle covers:
| Item | What it means | Usually included? |
|---|---|---|
| The boiler | The unit itself, sized for your home | Yes |
| Gas Safe installation labour | Fitting by a Gas Safe registered engineer | Yes |
| Flue kit | Standard horizontal/vertical flue | Yes (standard only) |
| Magnetic system filter | Captures sludge to protect the boiler | Usually |
| Wireless / smart thermostat | Often on combi swaps | Often |
| System cleanse or power flush | Chemical cleanse standard; full power flush may cost extra | Cleanse yes, power flush varies |
| Commissioning + Building Regs notification | Engineer registers the install with Gas Safe / Building Control | Yes |
| Manufacturer guarantee | Up to 10 or 12 years on some brands, if registered | Yes, if registered |
"Is it really included?" checklist
- Is the flue kit for a standard flue, or could yours be charged as non-standard?
- Is it a chemical cleanse or a full power flush — and which does your system need?
- Is the thermostat a basic wireless unit or a smart one?
- Who registers the guarantee — you or the installer?
- Is removal of the old boiler and making good included?
The guarantee matters for your longer-term cover decision — see new boiler warranty and 10-year cover.
4. How much should an online boiler quote cost in 2026?
These are indicative UK ranges for 2026, last checked this year — confirm live figures on each provider's own page. They are illustrative, not endorsements, and the "from" figures are starting prices for the cheapest standard jobs.
| Job type | Indicative price (from) | Typical range |
|---|---|---|
| Combi replacement (like-for-like swap) | from ~£1,500–£1,800 | £1,800–£3,500 |
| System / regular boiler replacement (like-for-like) | from ~£1,800 | £1,800–£3,500 |
| System / regular conversion to combi | from ~£3,000 | £3,000–£4,500+ |
| Back-boiler conversion to combi | from ~£3,000 | £3,000–£5,000+ |
| Median combi swap (online-quote sample, Jan–May 2026) | ~£2,300 | |
| UK average new boiler + install | ~£2,400 | |
What drives your number: boiler type and brand, fuel, your location, install complexity, guarantee length, and whether the boiler is being moved. For a deeper breakdown see new boiler cost in 2026, boiler installation cost breakdown and our boiler replacement cost guide. The best combi boilers for 2026 guide compares the units behind these prices.
5. When can a "fixed" price actually change?
This is the part installer-owned pages tend to gloss over. A fixed quote is conditional on the photos and survey matching reality. Here's the honest version.
| Stays fixed when… | Can change when… |
|---|---|
| Property matches your declared answers | System "not as described" (e.g. more radiators, different boiler type) |
| Standard flue position and length | Non-standard or extended flue, or an asbestos flue |
| Boiler stays in the same place | You ask to move the boiler |
| Existing gas supply is adequate | Gas pipe needs upsizing for the new boiler |
| Like-for-like swap | System upgrade (e.g. regular to combi) discovered mid-job |
| No hidden faults | Hidden problems found on the day |
Your rights: a price change must be agreed, not imposed. A reputable installer should explain any revision before proceeding and give you the option to decline. If work hasn't started and the revised price isn't acceptable, you can usually cancel — check the cancellation terms before you book, and keep the written quote.
6. How accurate are online quotes — and how to make yours accurate
A quick online quote is only as accurate as the detail you feed it. Garbage in, surprise on the day. Have this ready before you start:
- Current boiler make, model and type (combi, system or regular)
- Flue position — wall or roof, and roughly how long
- Number of radiators and bathrooms
- Fuel — mains gas, LPG or oil
- Clear photos of the boiler, flue exit, gas meter and nearby pipework
Get these right and the on-screen price should hold. Vague or wrong answers are the single biggest cause of a "fixed" price being revised later.
7. Online fixed-price installer vs local Gas Safe engineer
As a comparison site we don't sell installations, so here's the impartial trade-off. Neither is universally "better" — it depends on what you value.
| Factor | Online fixed-price installer | Local Gas Safe engineer |
|---|---|---|
| Speed | Often next working day | Depends on their diary |
| Price transparency | Instant, itemised, all-in | Quote after a visit; varies |
| Survey | Photo/video survey | In-person survey (catches more) |
| Finance | 0% APR / pay-monthly common | Rarely offered |
| Flexibility on odd jobs | Standard scope only | Can adapt to quirks |
| Relationship / snagging | Via central support | Direct, often same person |
| What's silently left out? | Non-standard extras quoted separately | May not include filter/cleanse/controls unless asked |
The honest summary: online tends to win on speed, transparency and finance; a good local engineer tends to win on flexibility, in-person assessment and an ongoing relationship for snagging. Compare inclusions, not just the headline number.
8. Finance & pay-monthly options
Most online installers offer pay-monthly plans, frequently with 0% APR on selected boilers and selected terms — commonly available up to around 48 months, with longer interest-bearing terms also offered. Deposits and the available terms vary by lender, boiler and amount borrowed, and finance is always subject to status and lender approval. Spreading the cost can make a higher-spec boiler affordable, but always check the total repayable and the APR.
Boiler finance is a regulated credit product. We don't give financial advice — see our full boiler finance and 0% APR pay-monthly deals guide for how the plans work and what to watch for.
9. Red flags & what to check before you book
- Gas Safe ID — the engineer must be on the register. Learn how to check a Gas Safe engineer.
- Who notifies Building Control — the installer should register the install; you should receive a certificate.
- Guarantee registration — confirm who registers it, and get proof.
- A written fixed quote — itemised, with the conditions that could change it stated in writing.
- No pressure to pay in full up front for unregulated "service plans" or "care plans" bundled in — these are not insurance.
Gas-safety bright line: any work on the gas supply, burner, flue, sealed circuit, gas valve, PCB or pressure-relief valve must be done by a Gas Safe registered engineer — never a DIY job and never an unregistered tradesperson. If you smell gas or suspect a leak, call the National Gas Emergency line on 0800 111 999.
10. How to compare quotes the smart way
Common guidance — echoed by the Energy Saving Trust, which advises not comparing on cost alone — is to get at least three quotes. With online tools that takes minutes.
- Get three quotes for the same boiler type and spec.
- Line up the inclusions side by side — filter, cleanse type, thermostat, flue, guarantee length.
- Compare the total cost, not just the monthly payment.
- Note each provider's price-change conditions and cancellation terms.
A cheaper headline price with a basic thermostat, no filter and a shorter guarantee can cost more in the long run than a dearer all-in quote.
11. After you've chosen: install day & what to confirm in writing
A standard combi swap is usually a one-day job. On the day, the engineer will isolate the old boiler, fit the new one, cleanse the system, commission it and test for safety.
Before they leave, confirm in writing:
- The Gas Safe / Building Regs certificate (or when it will arrive)
- The commissioning checklist completed in your guarantee booklet
- That the guarantee is registered with the manufacturer
- Any aftercare or annual-service condition that keeps the guarantee valid
Where a new boiler meets the cover decision
A new boiler's manufacturer guarantee typically covers parts and labour on faults — but it usually requires an annual service and doesn't cover everything boiler cover does (call-outs, controls, sometimes wider central heating). Don't pay twice for the same protection while the guarantee runs.
And if your current boiler is old, the smarter move may be replacement rather than another repair or cover renewal — our guide on whether to repair or replace your boiler walks through the maths. When the guarantee eventually lapses, that's the natural point to compare cover.
Disclosure: we are a boiler-cover comparison site and may earn a commission when you buy through some links. We feature a selected panel of providers, not the whole market. This page is general information, not financial or gas-safety advice. Insurance-based products are FCA-regulated; service and care plans are not insurance. Prices are indicative "from" figures, last checked 2026 — always confirm on the provider's own page.
Are online boiler quotes free?
Yes. Getting an online fixed-price quote is free and there's no obligation to buy. You answer questions, see a price, and can walk away — most providers don't even need your full details to show an initial figure.
How many quotes should I get?
At least three is the common rule of thumb, and the Energy Saving Trust advises not comparing installers on cost alone. Compare the same boiler type and spec, and look at what each quote includes — not just the headline price.
Can the fixed price change after I've booked?
Only if your property differs from what you declared, or the photos/survey reveal non-standard work — for example a non-standard flue, moving the boiler, gas-pipe upsizing or a system upgrade. A reputable installer should agree any revision with you first, and you can usually decline. Keep the written quote and check the cancellation terms.
How accurate are quick online quotes?
As accurate as the detail you give. Provide the correct boiler model and type, flue position, radiator and bathroom count, fuel and clear photos, and the price should hold. Vague answers are the main reason a "fixed" price gets revised.
Do I need new radiators with a new boiler?
Usually no. A standard swap reuses your existing radiators after a system cleanse. New radiators are typically only needed if existing ones are badly corroded or you're changing the heating layout.
Is online cheaper than British Gas or a local installer?
Often, yes — online installers tend to be competitively priced and several offer price-beat promises (for example, BOXT advertises beating like-for-like quotes by £50; check current terms). But always compare inclusions like-for-like, because a low headline price can leave out a filter, smart thermostat or longer guarantee.
What happens if the engineer finds a problem on the day?
They should stop, explain the issue and the cost to fix it, and get your agreement before continuing. You're not obliged to accept extra work at a revised price — but a genuine safety issue may mean the install can't safely complete until it's resolved. Anything touching gas, the flue or the sealed circuit must be done by the Gas Safe engineer.
Compare boiler cover the easy way
Compare boiler & central heating cover from a selected panel of UK providers and find a plan that fits your boiler and budget. Information, not advice — we show a chosen panel, not the whole market.
Compare boiler coverThis article is general information, not financial or gas-safety advice. We compare a selected panel of providers, not the whole market, and may earn a commission if you buy through our links. Always have gas appliances checked and repaired by a Gas Safe registered engineer; in a gas emergency call 0800 111 999. Prices are indicative UK guides for 2026 — confirm current prices on the provider's own site.