How to Tell Your Gas Heater's Age (And Why It Actually Matters)

Published 23 April 2026 · Written by Sidney — Licensed Gas Fitter, Pilot Gas Adelaide · 9 min read

TL;DR: Every gas heater has a data plate with a manufacture date or a serial number you can decode. Under 10 years old and it's a service-only story. Between 10 and 15, start watching for signs. Over 15, get it combustion-tested every winter and start budgeting for replacement. Over 20, you're living on borrowed time — and it's not always safe.

Why age actually matters

G'day. Sidney here. Every second week I climb into an Adelaide roof cavity or pull a wall furnace off its bracket and the customer asks the same question: "How old is this thing, mate?" Usually followed by, "Is it worth fixing?"

Age matters for four reasons, and they all cost you money or risk your safety.

1. Heat exchanger fatigue. The steel chamber that separates combustion gases from your room air expands and contracts every cycle. After 15–20 years of Adelaide winters, stress cracks are common. A crack means carbon monoxide mixing with your warm air — that's not a theoretical risk, it's the main cause of residential CO incidents in Australia.
2. Efficiency drop. A 1998 Braemar ducted unit is roughly 65% efficient. A 2024 one is closer to 92%. On a cold Adelaide July running the heater six hours a day, that gap is real money on the bill.
3. Parts availability. Manufacturers stop making control boards, specific fan motors, and custom-sized heat exchangers after the model's been out of production around 10–15 years. Generic parts cover a lot, but not everything.
4. Compliance. Older heaters sometimes don't meet current flue and ventilation standards. If they ever need modification — say you're renovating or re-roofing — a fitter may need to bring them up to current code, which can cost more than replacement.

Where to find the data plate

Every gas appliance sold in Australia has to carry a data plate. It's a metal or foil label with the brand, model, serial, gas type, input rating, and — critically — either a manufacture date or a serial number you can decode.

Ducted gas heating (Braemar, Brivis, Bonaire)

For ducted systems, the data plate is either:

• Inside the front access panel of the furnace (roof cavity or underfloor) — you'll usually need to unclip or unscrew a metal cover.
• On the side of the outdoor unit if it's an add-on ducted/refrigerated system.
• On a sticker inside the return air filter compartment (Bonaire MB series especially).

Take a torch and your phone. It's usually dusty, and the print can be faded. Snap a photo before you try to read it — zooming in on the photo is easier than squinting in a roof cavity.

Wall furnaces (Braemar Econ, Vulcan Heritage, Pyrox)

Behind the bottom grille or on the base. On Vulcans and older Pyroxes, pop the front cover off (usually two screws at the top) and the plate is on the left-hand internal panel.

Rinnai Energysaver space heaters

Right-hand side about a third of the way down, or on the rear panel if it's wall-mounted. Rinnai makes it easier than most — their serial format is very readable.

Flued gas log fires and Cannon/Regency units

Under the unit, usually visible if you lift the front grille or flame display. Some Regencys have the plate tucked behind the logs — a torch helps.

If you genuinely can't find the plate, ring us with the model name and any serial you can spot and we'll tell you over the phone. Happens a few times a week.

Decoding the serial number by brand

Not every data plate shows a "Manufacture Date" line. Plenty of older ones just give you a serial, and you have to decode it. Here's how, brand by brand, based on what we see in Adelaide homes.

Braemar (Seeley International)

Braemar serials on ducted units typically follow a format like YYMM embedded in the first four characters, or show the year and week more plainly on newer plates. A serial starting 1206... likely means June 2012. If in doubt, Seeley keeps records — you can ring their Adelaide HQ with the serial and they'll tell you exactly. For more on Braemar service intervals, see our Braemar service page.

Brivis

Brivis data plates since about 2005 have a clear "Date of Manufacture" field. Older SP523, Classic and HX series often only show a serial — the first two digits are usually the year. Serial 98... is 1998, 04... is 2004. Past 2010, the year is normally four digits. See our Brivis service guide for age-appropriate service scopes.

Bonaire

Bonaire's more modern plates list the month and year directly. The classic MB12 and MB16 from the 90s and early 2000s used a lot-number format — if yours looks like hieroglyphics, photograph it and send it through. We've been reading these for 12 years and have a cheat sheet.

Rinnai

Easiest in the business. Rinnai serials encode the date clearly. On an Energysaver 309, a serial like 23042560789 means year 23 (2023), month 04 (April), then a run number. Some older models use a similar YYMM prefix. Full guidance on our Rinnai service page.

If decoding feels like too much hassle, just book a service. We record the age, brand, model, serial and a combustion reading on every job, and leave you a sticker on the unit with the next service due date.

The Adelaide age guide

Here's the simple framework I walk homeowners through every day.

0–5 years: service only

A modern heater under five years old is almost certainly fine. Service every two years is enough, and warranty covers most major parts if anything fails. This is the easy phase. Keep the return air filter clean, keep a metre of clearance around the unit, and you're sorted.

5–10 years: still young, but watch

Annual or biennial service. Start noticing things — louder startup noises, longer ignition cycles, small gas bill creep. These are all early whispers. This is also when the first non-warranty repair often happens (ignition electrode, flame sensor, capacitor) — cheap to fix, $150–$350 most of the time.

10–15 years: middle age

Annual service non-negotiable. Every service, we do a combustion analysis — CO in the flue should stay under 100 ppm, ideally under 50. Fan motors start going. Control boards occasionally pack it in. If you've got a ducted system, ductwork and return air will need attention too. Repairs in this phase are usually worth it — a $500 fan motor on a good heater still has years of life ahead.

15–20 years: decision window

Here's where the honest conversation happens. A heater that's had every service and passes combustion testing can easily run safely past 20. A heater that's been neglected, has a rusting flue, or fails a combustion test is living on borrowed time. Budget for replacement within this window. Don't panic-replace — plan-replace.

20+ years: borrowed time

Some Rinnai Energysavers from the early 2000s still pass combustion testing and will outlive us all. Plenty of 25-year-old Brivis SP523s are still pumping out heat. Fine — if they pass testing, keep them going. But: every year, not every two. Full flue inspection. CO alarm in the house non-negotiable. Have a replacement quoted so you know the number and can pull the trigger the moment something major fails. Our warning signs guide is worth a read if you're in this bracket.

Service vs repair vs replace — a simple decision tree

This is the framework I'd use on my own parents' heater.

• Under 10 years old, working: Service. $189–$290.
• Under 10 years, not working: Repair, almost always. Manufacturer parts are available and cheap.
• 10–15 years, working but inefficient: Service + combustion test + honest quote on bringing it up to spec.
• 10–15 years, needs repair under $600: Repair.
• 10–15 years, needs repair over $600: Weigh it up. Factor in remaining life. Often still worth repairing.
• 15+ years, needs repair over $600: Usually replace. A new ducted system is $4,500–$8,000 installed, a new wall heater $2,500–$4,500. A $1,200 repair on a 17-year-old unit buys maybe 3 more years, not 15.
• Any age, failed combustion test or cracked heat exchanger: Replace. Don't mess with this one. See our carbon monoxide safety guide.
• Any age, unit is non-flued or a heritage open-flame room heater: Replace. Safety regulations have moved on.

If you want help running the numbers on repair vs replace, we quote both sides for free — see repair pricing and installation.

What we still see in Adelaide homes

Some Adelaide-specific patterns worth knowing, after twelve years of doing this.

• Brivis SP523 ducted units from the mid-90s are still everywhere in Tea Tree Gully, Golden Grove and Salisbury. Plenty of them running. Fan motors on these have been rebuilt once or twice. Replacement when the heat exchanger finally goes.
• Bonaire MB12 and MB16 are common in 80s–90s builds across Marion, Mitcham and the southern suburbs. Many still pass combustion testing with a proper service. Parts still obtainable.
• Braemar Econ wall furnaces from the 2000s sit in thousands of Norwood and Prospect homes. Reliable but the heat exchangers corrode — 15+ years is when I'd start testing carefully every year.
• Rinnai Energysaver 309s and 556s installed late 90s / early 2000s are the hard-to-kill ones. Seen plenty of 25-year-old units still passing. Rinnai build quality is the reason.
• Vulcan Heritage wall furnaces — if yours is pre-2005, get it tested. Parts are dwindling and heat exchangers corrode hard in SA conditions.

For the authoritative regulatory framework, the SA Department for Energy and Mining publishes SA gas safety requirements. Energy Safe Victoria's public education materials on heater age and safety are worth a read too — esv.vic.gov.au.

FAQ

My heater has no data plate I can find — what now?

Ring us with the brand name, rough model name and any serial number visible elsewhere (sometimes the gas valve or burner has its own date code). We'll usually work it out or come and have a look during a service.

Does the age matter if the heater still works?

Yes — because "still works" isn't the same as "still safe." A 22-year-old heater can blow warm air and still be leaking CO. Age means more frequent safety checks, not automatic replacement. See our service frequency guide.

What if the previous owner left no records?

That's most houses we visit. First service, we document everything from scratch — data plate photo, combustion reading, filter condition, visual flue inspection. You then have a baseline for every year after.

Is it ever worth replacing a young heater?

Rarely. If a modern heater fails in the first 10 years, it's almost always a specific component — and the rest of the unit is fine. Repair is usually the right call.

Does moving house affect heater age relevance?

If you're buying: absolutely ask for the heater's age and last service. Factor it into your offer. If you're selling: a current service certificate reassures buyers. We do pre-sale heater inspections for exactly this reason.