How old is my boiler?

Two dates, and which one you need

A boiler has a manufacture date and an installation date, and they are rarely the same. It can sit in a merchant's warehouse for months before an engineer fits it. For a rough sense of how much life is left, the manufacture date is enough. For the date a guarantee runs from, you need the installation date.

Vaillant's domestic boiler guarantee shows how the two relate. It commences from the date of installation, and Vaillant asks for proof of purchase, an invoice or a completed Benchmark logbook, “without which the guarantee will commence from the date of manufacture, as shown on the boiler data plate”. The manufacture date is the fallback, not the headline.

So the job splits in two. Read the plate for what the boiler will tell you, then find the paperwork for the date that decides a guarantee.

Key facts

• Some makes print a date of manufacture on the data plate. Where they do, that is the fastest rough answer.
• The installation date sits on the Benchmark logbook, the building control certificate or the installer's invoice.
• Gov.uk says a scheme-registered installer “will also give you a certificate within 8 weeks of completion which can be used as evidence of compliance”, and that “If needed, they'll tell your local authority about work on your behalf.”
• Never take the front casing off to look. That is inside a gas appliance, and it is work for a Gas Safe registered engineer only.

Step 1: read the data plate

The data plate is a label carrying the model, the serial number and the appliance details. On many boilers it sits behind the drop-down flap on the front, on the underside of the casing, or on a sticker on top. Where the maker prints a date of manufacture on it, you have your rough age in one look.

Photograph the whole plate rather than copying digits by hand. Serial numbers are long, and one wrong character sends a lookup back empty.

There is one hard limit on where you look. The flap, the underside and the top of the casing are fair game. Removing the front panel is not: that is inside a gas appliance, and it is engineer-only work. If you can see nothing without unscrewing something, take the paperwork route below.

If you ever smell gas, do not touch any electrical switches, do not smoke, put out all naked flames, open the doors and windows, and contact the National Gas Emergency Service immediately on 0800 111 999.

Step 2: let the manufacturer confirm it

The serial number is not a date you can decode. What it does is unlock the manufacturer's own record of your boiler. Worcester Bosch is explicit on its guarantee check: “Simply enter your 23 digit serial number below to find your guarantee expiry date.”

Note what comes back. These are guarantee tools, so the answer is an expiry date, and an expiry date read alongside the published guarantee length gets you close to the installation date. Worcester Bosch attaches a condition worth reading first: “Please be aware that all dates and guarantee validity of boilers are subject to an annual service being undertaken every year since installation, as outlined in the Guarantee Terms & Conditions.”

If the guarantee has already run out, an online checker often gives you nothing at all, which is the position most people asking this question are in. Do not stop there. Our guide to checking a boiler warranty sets out who to ring when the online tool comes back blank, and the paperwork route below works whether the guarantee is alive or dead.

If a third-party site offers to decode your serial number into a build date, confirm it with the maker before acting on it.

Step 3: find the installation date

This is the date a guarantee runs from, and it lives in one of three places.

The Benchmark logbook first. Benchmark is the commissioning checklist your installer fills in on the day, and Baxi tells homeowners to “Make sure your installer completes the Benchmark commissioning checklist”. Vaillant treats a completed logbook as proof of purchase in its own right. It is usually in a drawer near the boiler, or stapled inside the user manual.

The building control certificate second. Gov.uk explains the scheme: “An installer (for example of windows or boilers) who's registered with a scheme can self-certify that their work complies with building standards”. It then says what you should have received: “They'll also give you a certificate within 8 weeks of completion which can be used as evidence of compliance – it will also show up in solicitors' searches if you come to sell your home.” If you bought the house with the boiler already in it, check the conveyancing pack before you check anywhere else.

The installer's own records third. The business that fitted it will have a dated invoice, and a phone call is often quicker than a paper search. The logbook and the certificate both name the installer.

If none of the three turns up, try your local authority's building control team next. Gov.uk says of a scheme-registered installer that “If needed, they'll tell your local authority about work on your behalf”, so a record may sit there even when your own copy is long gone. If nothing was ever notified, gov.uk is direct: “Without approval you will not have the certificates of compliance you may need when you want to sell your home.” Treat the boiler as undated, go by the data plate, and get the gap sorted before you sell.

What your boiler's age actually decides

Three real decisions hang on the number, and they hang on it differently.

Whether the guarantee is still alive. Guarantee length runs from installation, and Vaillant, Ideal Heating and Baxi all ask for the boiler to be registered within 30 days. Vaillant publishes the consequence of missing that window: the guarantee reverts to 12 months from the date of installation. Other makers word the consequence differently, so read your own maker's terms rather than assuming. Our guide to checking a boiler warranty walks through the check, and our guide on what to do when a warranty has expired covers your options once it has run out.

Whether to repair it or replace it. Age is one input, alongside the repair cost, how often the boiler has failed before, and how easily parts for a discontinued model can still be found. It is a judgement rather than a cut-off, and our guide on repairing or replacing a boiler sets out how to weigh it up.

What a cover plan will pay towards a repair. On our boiler and central heating module, parts and labour are covered up to £500 in each 12-month period of your plan while the boiler is under 7 years old, and up to £200 once it is over 7 years old, with anything above the limit paid by you. That step is the one place age genuinely changes what you get. Our page on cover for older boilers goes through what the lower limit does and does not stretch to.

Boiler age FAQs

The small print on our boiler cover

• Cover limit: parts and labour up to £500 in each 12-month period of your plan while the boiler is under 7 years old, and up to £200 once it is over 7 years old. Anything above that you pay.
• Defects: if our engineer identifies a fault that was already there before your plan started, the terms class it as a defect, and repairing that part is not covered.
• Call-outs: Monday to Friday, 08:00 to 18:00. We aim to get an engineer out to you within two working days.
• £95 call-out fee, paid in advance: in your first 30 days, for faults the plan does not cover, for no-access visits and for an annual service asked for early. Your cover is running throughout those first 30 days, so the fee is the only difference.
• Payment and agreement: payment is monthly, and a 12-month agreement period begins as soon as you request a service. Leaving inside it costs the remaining months, or 75% of the outstanding balance as a one-off.
• Cooling off: 14 days from the start of the agreement, ending once a service is carried out.
• We work with a national network of thousands of Gas Safe registered engineers. Smart Plan is a service plan, not insurance, from UK Boiler Company Ltd, trading since 2014.

Know the age? Tell us about your boiler.

Tell us the make, the model and roughly how old it is, and we will tell you what the boiler and central heating module would cover on it. The cover limit steps down once the boiler passes 7 years old, and the small print above sets out the limits, the fee and the agreement period in full.

Helpful links

• How to check your boiler warranty
• Boiler warranty expired? What to do next
• Boiler repair or replace
• Boiler cover for older boilers
• Boiler & central heating cover
• Worcester Bosch guarantee check
• Vaillant domestic boiler guarantee terms
• Gov.uk: using a competent person scheme