How long do gas heaters last?

Most gas heaters last 15 to 20 years with regular servicing. Signs they need replacing include frequent breakdowns, uneven heating, rising gas bills, and visible corrosion.

When should I replace rather than repair my gas heater?

If repairs cost more than 50% of a new unit, the heater is over 15 years old, or the heat exchanger is cracked, replacement is the better investment.

How much does it cost to replace a gas heater in Melbourne?

Gas heater replacement in Melbourne typically costs between $1,200 and $3,500 fully installed depending on the system type and size.

When Should I Replace My Gas Heater? Melbourne Guide

Christopher Unwin
May 3
2 min read

Updated: May 3

When Is It Time to Replace Your Gas Heater?

Most gas heaters have a design life of 15–20 years. But age alone doesn't determine when to replace — condition does. Here's how to think about it honestly.

Replace If the Heat Exchanger Has Cracked

A cracked heat exchanger is a safety issue — full stop. It cannot be repaired, only replaced. If a licensed gas fitter finds a cracked heat exchanger during inspection, the unit must be condemned and replaced. There is no economical or safe workaround. This is the number one reason we condemn heaters at ATC Plumbing.

Replace If Repairs Cost More Than Half the Replacement Price

If your heater needs a major component — a control board, gas valve, or heat exchanger — and the part plus labour costs more than half what a new unit would cost installed, replacement is almost always the better investment. A new unit comes with a full warranty. A repaired 15-year-old unit does not.

Replace If It Has Had Repeated Failures

One repair in 10 years is normal. Two or three repairs in 24 months means the unit is at end of life. Every repair is a band-aid on an ageing system — and eventually the band-aids stop working. If your heater is constantly breaking down, replacement is the more economical choice in the long run.

When Repair Is Still Worth It

If your heater is under 12 years old, has a sound heat exchanger, and the fault is a simple component — thermocouple, ignition module, pilot assembly — repair is almost always worthwhile. These parts typically cost $150–$400 to supply and fit, compared to $1,500–$2,500 or more for a new ducted system installed.

Replacement Options in Melbourne

If replacement is the right call, your main options are a like-for-like gas ducted system, a multi-head reverse-cycle air conditioning system (no gas required), or a combination approach. Given Victoria's long-term gas substitution roadmap, it's worth discussing your energy direction when choosing. ATC Plumbing can provide honest advice and quotes across all options. Call 1300 282 758.