Why the age of your boiler matters
The age of a gas boiler is the single biggest clue to whether you should service it, repair it, or replace it. A well-maintained modern combi typically lasts 10–15 years. After that, efficiency drops off, parts get harder to find, and repair bills start catching up with the price of a brand-new A-rated boiler.
The good news: you don't need an engineer to work out the year. Every UK boiler carries a serial number with the date of manufacture built in — you just need to know where to look and how to read it.
Step 1 — Find the data-plate
The data-plate is a small silver or white sticker printed with the model name, GC number, gas type and serial number. On most modern boilers it sits in one of three places:
- The underside of the case, facing the floor.
- Behind the flip-down front cover (open it like a laptop lid).
- Printed inside the front panel itself once you unclip it.
Take a clear photo — it makes reading the small text much easier, and it's what a heating engineer will ask for anyway.
Step 2 — Read the serial number for your brand
Every manufacturer encodes the date slightly differently. Find your brand below.
Worcester Bosch
Where to look: Data-plate behind the front panel or on the underside of the boiler.
Date format: Serial starts with a 7-digit block, then a 4-digit date code. The 4-digit block reads YYWW — the first two digits are the year, the last two the week of manufacture.
Example: 7 716 192 000 · 2214 → made in week 14 of 2022.
Vaillant
Where to look: Silver sticker on the underside of the case, or printed inside the front panel.
Date format: Long serial number where digits 4 and 5 give the year, and digits 6 and 7 give the week.
Example: 21 20 3400200123456 → made in week 34 of 2020.
Ideal (Logic, Vogue, Mexico)
Where to look: Sticker inside the front cover — flip the cover down and look at the top edge.
Date format: Starts with a GC number followed by a long serial. The first 8 characters usually contain the manufacture date as DDMMYYYY or the year in positions 5–8.
Example: E11 000 000 21032019 → made on 21 March 2019.
Baxi (also Potterton, Main, Heatline)
Where to look: Data-plate on the underside of the case.
Date format: 13-character serial. Characters 4–5 = year, characters 6–7 = week.
Example: BXI 21 47 12345 → made in week 47 of 2021.
Glow-worm
Where to look: Sticker on the underside or inside of the front panel.
Date format: Same convention as Vaillant (same parent group). Digits 4–5 are the year, 6–7 are the week.
Example: 18 09 1000200012345 → made in week 9 of 2018.
Vokèra
Where to look: Silver data-plate inside the case, near the gas inlet.
Date format: Serial ends with a date block in the form MM/YYYY.
Example: …SN 12345 06/2016 → made in June 2016.
Viessmann
Where to look: Data-plate visible without removing the cover, top-left inside the door.
Date format: Uses a 16-digit serial. The last 4 digits are usually YYYY (year of manufacture).
Example: 7 000 000 000 000 2023 → made in 2023.
Alpha, Ariston, Ferroli, Sime and other Italian brands
Where to look: Data-plate inside the front cover or on the underside.
Date format: Most print the manufacture date in plain text near the serial, either as MM/YY or DD/MM/YYYY. If not, the year is usually encoded in the middle of the serial.
Example: Look for a stamped date beside the CE mark.
Step 3 — Decide: service, repair or replace?
- 0–8 years old: keep it. Book an annual service to protect the manufacturer warranty and efficiency.
- 8–12 years old: service yearly and repair sensibly. Start budgeting for replacement so you're not caught out mid-winter.
- 12–15 years old: weigh up any repair over £300 against a new A-rated boiler — the fuel savings often pay it back within a few years.
- 15+ years old: replacement is usually the smart move. Parts are scarce, efficiency is well below modern boilers, and breakdowns become more frequent.
Can't find the serial? We'll help
If the data-plate is faded, hidden or missing, send us a photo of the boiler and we'll do our best to date it from the model number and installation clues. It's a free service to anyone in Brighton, Hove or the surrounding Sussex area.
