Warranty
Combi boiler warranty comparison
Standard warranties run 5 to 10 years. Extended warranties go up to 12 years if a brand-accredited installer fits the boiler and registers it within 30 days. Skipping the annual service is the single biggest reason warranty claims get rejected.
Side by side
Warranty terms by brand
| Brand | Standard | Extended | Covers |
|---|---|---|---|
| Worcester Bosch | 5 years | Up to 12 years | Parts and labour |
| Vaillant | 7 years | Up to 10 years | Parts and labour |
| Viessmann | 10 years | Up to 12 years | Parts and labour |
| Ideal | 5 years | Up to 12 years (Vogue Max only) | Parts and labour |
| Baxi | 7 years | Up to 10 years (Baxi 800) | Parts and labour |
Brand
Worcester Bosch
Standard cover
5 years
Extended (max)
Up to 12 years
What is covered
Parts and labour
How to unlock the extended term
Worcester Accredited Installer fits a Greenstar 8000 Life and registers within 30 days.
Common voids
Missed annual service, non-Gas Safe install, registering after the 30 day deadline.
Brand
Vaillant
Standard cover
7 years
Extended (max)
Up to 10 years
What is covered
Parts and labour
How to unlock the extended term
Vaillant Advance installer fits an ecoTEC Plus and registers within 30 days.
Common voids
Missed annual service, non-Advance installer, sludge damage where no MagnaClean is fitted.
Brand
Viessmann
Standard cover
10 years
Extended (max)
Up to 12 years
What is covered
Parts and labour
How to unlock the extended term
Viessmann installer registers via the partner portal. Limited models qualify for the 12 year tier.
Common voids
Missed annual service, third-party parts, missed registration.
Brand
Ideal
Standard cover
5 years
Extended (max)
Up to 12 years (Vogue Max only)
What is covered
Parts and labour
How to unlock the extended term
Ideal Max Accredited Installer fits a Vogue Max with a system filter and registers within 30 days.
Common voids
Skipping the system filter, missed service, non-accredited install.
Brand
Baxi
Standard cover
7 years
Extended (max)
Up to 10 years (Baxi 800)
What is covered
Parts and labour
How to unlock the extended term
Baxi-approved installer registers and the system filter is included.
Common voids
Missed annual service, non-approved installer, third-party PCB swap.
Avoidable voids
Eight things that void a warranty
Every brand reads slightly differently, but these are the universals. Avoid them all and the warranty stays in force.
Missing a single annual Gas Safe service.
Installation by a non-Gas-Safe engineer or DIY.
Non-accredited installer (kills the extended term, not the standard one).
Registering after the 30 day deadline (varies by brand).
Using third-party parts not approved by the manufacturer.
Skipping the system filter (MagnaClean) on a brand that requires it.
Sludge damage where no powerflush was done on an old system.
Modifying the boiler or its controls without manufacturer sign-off.
Decision
Extended warranty vs boiler cover
Two ways to protect against post-warranty repair costs. They are similar but not the same.
Manufacturer extended warranty
Bought up front through your installer when the boiler is new. Locks in 10 to 12 years of cover. Cheaper per year than third-party cover plans, but only covers the boiler itself, not the rest of the heating system.
Boiler cover plan
Bought monthly from a third party (British Gas, HomeServe, Hive, others). Includes annual service plus breakdowns and parts. Covers the wider heating system. More expensive but more flexible.
FAQs
Common questions
Which combi boiler has the longest warranty?v
Worcester Bosch Greenstar 8000 Life and Ideal Vogue Max both top out at 12 years when fitted by an accredited installer and registered within 30 days. Viessmann offers 10 to 12 years on selected models.
Does the warranty cover labour as well as parts?v
Yes for the major UK brands listed here. Worcester, Vaillant, Viessmann, Ideal, and Baxi all cover parts and labour during the warranty period. Some smaller brands only cover parts, which leaves you paying the call-out and labour for repairs.
How do I register the warranty?v
Through the manufacturer's website, usually within 30 days of installation. Some installers do it for you, but it is your responsibility to check. Keep the Benchmark certificate, the registration confirmation email, and every annual service record.
Do I need an annual service to keep the warranty valid?v
Yes. All major UK brands require an annual Gas Safe service. Miss one year and the warranty typically becomes void. Set a reminder for the same month each year, autumn is the best time so issues are caught before peak winter.
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