How long does ducted heating really last in Ballarat?
Honest lifespans for furnaces, ductwork, evaporative units and heat pumps in the Central Highlands, why the brochure numbers do not apply here, what kills a system early, and the line where repairing stops making sense.
12 to 18 years, not 15 to 20.
The commonly quoted figure for a ducted gas furnace is 15 to 20 years. That is a national average, and Ballarat is not average. Realistically, expect 12 to 18 years here. The reason is runtime, not build quality. Ballarat sits at roughly 435m in the Central Highlands and is one of the coldest population centres in Victoria, with frosts running May through September. A furnace here racks up far more running hours per year than the identical unit in a bayside suburb, and appliances age on hours, not on birthdays.
The part that decides the life of the whole appliance is the heat exchanger. Everything else on a furnace is replaceable at sensible money: fan motors, gas valves, ignition, controllers. The heat exchanger is not, and it is the component that eventually fails from thermal cycling, expanding and contracting through thousands of heat-up and cool-down cycles until a crack opens. When it cracks, combustion products including carbon monoxide can enter the air stream, which is why a cracked heat exchanger is the end of the conversation regardless of what the rest of the unit looks like.
Ducts, evaporative units and heat pumps.
- Ductwork, 20 to 25 years. It will often outlive one or even two furnaces, so it does not automatically get replaced with the unit. What it does is quietly get worse. Flexible duct to AS 4254.2 loses effective R-value as the insulation compresses and sags over decades, joints work loose, and rodents in a Ballarat roof cavity chew it. We inspect the ducts whenever we change a furnace and tell you honestly whether they have another decade in them or whether reusing them will waste the new unit’s efficiency.
- Evaporative cooling, 10 to 15 years. The unit lives on the roof taking full UV and full frost, which is a hard life. One local advantage: Ballarat’s water supply is relatively soft compared with hard-water districts, which is kind to pads and pumps because they scale up more slowly. The winter kit matters here, an uncovered unit through a Central Highlands winter ages faster. See the evaporative cooling page.
- Reverse-cycle outdoor unit, 12 to 18 years. Ballarat is actually kind to these. Being inland, there is essentially no salt load, so the outdoor coil does not suffer the corrosion that eats condensers in coastal towns. The local wear factor is frost instead. Through a Central Highlands winter a heat pump runs defrost cycles constantly, and that cycling, plus the reversing valve and fan motor work it demands, is what ages the unit here rather than rust. More on the refrigerated cooling page.
What actually kills a system before its time.
Two things, and one is far worse than the other.
Undersizing is the killer. A unit too small for a Ballarat heat load runs flat out all winter, never quite reaches setpoint on a one degree morning, and simply wears out sooner while costing more to run the whole time. It is a defect that gets built in on day one and cannot be serviced out. This is why we size off a room-by-room heat-load calculation accounting for ceiling height, glazing, wall construction and insulation, rather than floor area. A system sized for a milder climate is undersized the moment it arrives in Ballarat, and the choosing an installer guide explains how to spot that in a quote before you sign it.
No servicing is the other. Annual servicing matters more here than in a milder town precisely because the unit works so much harder. A serviced heater burns cleanly, does not choke itself on a blocked filter, and gets its flue and heat exchanger looked at before a fault becomes a failure. At $160 to $280 a year including a carbon monoxide test, it is cheap insurance against a $10,000 replacement arriving three years early. The service and repair page covers what we actually check.
Behind those two sit the smaller ones: a cheap unit chosen on headline price, ducts crushed at install so the fan fights the system for twenty years, and a system with no zoning heating empty bedrooms for a decade.
Where the line sits.
Our rule of thumb, and we will give you the same answer on site:
- Repair under a third of replacement cost, unit under twelve years old, repair it.
- Repair over half of replacement cost, unit past fifteen, replace it. You are pouring money into a unit that has other failures queued behind this one.
- Cracked heat exchanger, any age, any price, replace it. That is the carbon monoxide part and it is not a component worth gambling on.
Between those lines it is a judgement call about how many more Ballarat winters you want out of it.
A worked example, Ballarat East.
A weatherboard home in Ballarat East with a sixteen-year-old ducted gas furnace. No heat in June. The fault was a failed gas valve plus a tired combustion fan, quoted at $1,180 to put both right. Replacement with a 6-star unit reusing the existing ducts was $8,600. The repair was under fifteen percent of replacement, so on price alone it was an easy repair. But the CO test came back clean and the heat exchanger inspected sound, which was the part that actually decided it. We did the $1,180 repair. That unit has three to five winters left in it, the owner knows that, and they can plan the replacement instead of being ambushed by it in July. Had the heat exchanger shown a crack, the same job would have been a replacement conversation no matter how cheap the valve was.
Know where your system sits.
The best time to replace a ducted heater is on your terms, in autumn, with quotes compared properly, not on the coldest morning of the year when you will take whoever can come today. If your unit is past twelve, get it serviced annually and ask the technician each year for a straight read on the heat exchanger and the flue. That gives you a runway rather than a surprise. An annual service to AS 4575, the standard for servicing domestic gas appliances, is what puts a carbon monoxide test and a heat-exchanger inspection on the record each year.
One planning point specific to here. If the unit being replaced is a roof-mounted evaporative one and your home sits in a City of Ballarat heritage overlay, a replacement visible from the street can need a planning permit, which adds weeks to a job you were hoping to book quickly. Our compliance and permits guide sets out what to check. The cost guide sets out what a replacement runs to in 2026, and if the old unit is gas it is worth reading the gas vs reverse cycle comparison before defaulting to like-for-like, because the answer for a Ballarat home with solar is not always the obvious one.
Where we work.
Not sure how much life is left in your system?
Free measure, honest read on repair versus replace, fixed written quote either way.