Quick answer
A Baxi boiler warranty commonly runs between 2 and 10 years, with the exact length depending on the model and whether you registered it in time — usually within around 30 days of installation.
To keep the guarantee valid you generally must register on time, have the boiler serviced every 12 months by a Gas Safe registered engineer, and keep the Benchmark logbook completed. The warranty covers defects in the boiler itself, not poor installation, neglected system maintenance or the wider heating system.
Always confirm your own model's terms with Baxi or your installer, as they vary.
If you've had a new Baxi boiler fitted, the manufacturer's guarantee is one of the most valuable things that came with it — but only if you keep it valid.
Baxi (part of the BDR Thermea group, alongside brands such as Potterton and Heatrae Sadia) offers warranties that range widely depending on the model and how it was registered.
Below we explain the typical lengths, the conditions attached, what's covered, how to make a claim, and how a warranty differs from the boiler cover policies many homeowners also take out.
How long is a Baxi boiler warranty?
There is no single answer, because the length depends on the model and, crucially, on whether it was registered within the stated window. Across Baxi's current combi, system and heat-only ranges, guarantees commonly fall somewhere between 2 and 10 years.
Entry-level models tend to sit at the lower end; flagship combis and bundles bought with a filter or installed by an accredited installer often reach the higher figure.
A few points worth understanding:
- The headline length you see advertised (for example "10-year guarantee") usually assumes you register in time and have the boiler serviced every year. Miss those steps and the term can drop back to the shorter standard period.
- Promotional or installer-led offers can lengthen the term beyond the standard figure for the same model, so two identical boilers can carry different warranties.
- Terms change over time. The figure that applied when your boiler was made may differ from what Baxi advertises today.
Always confirm your own model's terms. The only reliable source is the guarantee paperwork supplied with your boiler, or your registration confirmation. Treat the ranges here as a general guide, not a promise for your specific unit.
The conditions that keep your warranty valid
A manufacturer's guarantee is conditional. With Baxi, three requirements come up again and again, and falling short of any of them is the most common reason a claim is refused.
1. Register within the stated window
Baxi normally asks you to register the boiler within a set period after installation — often around 30 days. Registration is free and is usually done online or by phone. Without it, you may default to a shorter standard guarantee, or have no extended cover at all. Your installer sometimes registers on your behalf, but don't assume it has been done — check.
2. An annual service by a Gas Safe registered engineer
To keep the guarantee live, the boiler must be serviced every year by a Gas Safe registered engineer. The service must be carried out on time (typically within a window around each anniversary of installation) and recorded properly.
Skipping a year — or letting it slip late — is enough to invalidate the remaining term on many policies. Keep your receipts and service records; you may be asked to produce them when you claim.
3. A completed Benchmark logbook
The Benchmark Checklist is the industry commissioning record that your installer should complete and sign at handover, then update at each annual service. A missing or blank Benchmark logbook is a frequent sticking point in warranty disputes, so make sure yours was filled in on day one and is kept with the boiler documents.
| Condition | Why it matters |
|---|---|
| Register in time | Unlocks the full advertised length rather than the shorter standard term |
| Annual Gas Safe service | Keeps the guarantee live year on year; missing one can void the rest |
| Benchmark logbook completed | Proves correct commissioning and ongoing servicing if you claim |
| Installed by a competent person | Faults caused by poor installation are typically excluded |
What a Baxi warranty covers — and what it doesn't
A manufacturer's guarantee is designed to cover defects in the boiler itself — faulty parts and manufacturing problems within the warranty period. If a covered component fails, Baxi arranges repair or replacement of that part, and the associated labour, under the guarantee terms.
What it generally does not cover:
- Faults caused by poor installation, or by work done by someone who wasn't Gas Safe registered.
- Problems from sludge, scale, lack of an inhibitor or a missing/neglected system filter — i.e. issues from how the wider heating system was looked after.
- Accidental damage, frost damage, or faults arising from low system pressure that wasn't maintained.
- Wider system parts that aren't the boiler — radiators, most thermostats, external pipework and so on.
- Consequential issues where the annual service or registration conditions weren't met.
This is exactly where many homeowners get caught out: the boiler is still "in warranty" on paper, but the claim is declined because a service was missed or the fault sits outside the boiler. It's worth reading our explainer on what boiler cover actually is to see where a warranty ends and a separate policy begins.
How to make a Baxi warranty claim
If you think your boiler has a covered fault, the broad process is:
- Do the safe basic checks first. Confirm there's power and the fuse hasn't tripped, the programmer/thermostat is calling for heat, and the pressure gauge reads roughly 1 to 1.5 bar when cold. If pressure is low, you can top it up via the filling loop, and you can bleed radiators if they're cold at the top. A single front-panel reset is fine. Beyond that, stop.
- Note the fault code. Most Baxi boilers show an error code on the display. Write it down — it speeds up the diagnosis.
- Contact Baxi. Register the fault through Baxi's service line or website. Have your model name, serial number, installation date and registration/service history to hand.
- Have your records ready. Be prepared to show proof of annual servicing and your Benchmark logbook — these are what validate the claim.
- A Baxi or approved engineer attends. Repairs under warranty are carried out by Baxi's own engineers or approved partners, not by any engineer you choose.
Safety first. Never attempt DIY repairs on the gas valve, gas pipework, the flue, the sealed/pressurised circuit, the pressure relief valve or behind the boiler casing. These are gas-safety-critical and must only be touched by a Gas Safe registered engineer.
If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Warranty vs boiler cover: what's the difference?
People often use "warranty" and "boiler cover" interchangeably, but they're not the same thing.
- The manufacturer's warranty is free with the boiler, fixed in length, and only covers manufacturing defects in that boiler while the conditions are met.
- Boiler cover is an ongoing policy you pay for (monthly or annually). Depending on the plan it can cover breakdowns, parts and labour, and sometimes the wider heating system or controls — and it usually continues after the warranty expires. Many plans also include or bundle the annual service that keeps a warranty valid.
The two can work together: your warranty handles boiler defects for the first few years, while a cover policy can fill the gaps (system faults, controls, an included service) and take over once the guarantee runs out.
If you're weighing up whether to pay for a policy at all, our guide on whether boiler cover is worth it walks through the trade-offs, and you can line up plans side by side on our best boiler cover comparison.
Does a Baxi warranty include the annual service?
Generally no — the warranty requires an annual service to stay valid, but you arrange and pay for that service yourself unless it's bundled into a separate cover plan. Always use a Gas Safe registered engineer and keep the record.
What happens if I miss a year's service?
Missing or delaying the annual service can invalidate the remaining warranty, even if the boiler is otherwise still within its term. Check your specific guarantee wording, as the exact rules vary by policy.
Is the warranty transferable if I sell my home?
Many Baxi guarantees can transfer to a new homeowner, sometimes for the remaining period, provided the servicing record is intact. Confirm the transfer process with Baxi, as terms differ by model and registration.
I've lost my paperwork — how do I check my warranty length?
Contact Baxi with your boiler's serial number and installation address; if you registered, your details should be on file. The serial number is usually on a label on or inside the boiler casing or on the original Benchmark logbook.
Does the warranty cover my whole heating system?
No — it covers the boiler itself. Radiators, most controls and external pipework sit outside it. That's the gap a separate boiler cover policy is designed to address.
It pays to compare boiler cover — prices and cover levels vary more than most people expect.
Compare boiler cover for your Baxi
See how cover plans line up on price, callouts and what's included — and find one that complements your manufacturer warranty.
Compare boiler coverThis article is general information, not advice, and reflects indicative 2026 terms for a selected panel of providers rather than the whole market. Warranty lengths and conditions vary by model and registration — always confirm the exact terms for your own Baxi boiler with Baxi or your installer.