Age, heat exchanger condition, parts availability and running cost. Four factors decide it — not a sales pitch.
1. Age of the unit
Ducted gas heaters typically last 15 to 20 years, wall furnaces a little longer with servicing. Under ten years, repair is almost always the right call. Past fifteen, every repair needs to be weighed against remaining life.
2. Heat exchanger condition
This is the deciding factor. A cracked or corroded heat exchanger is not a repairable item on most residential units, and it's a genuine safety issue. If the exchanger has failed, replacement is the only responsible recommendation.
3. Parts availability
Some older models have excellent parts support in Australia; others are effectively orphaned. We check availability before quoting so you aren't left waiting weeks in the middle of winter.
4. Running cost
Older units often run at much lower efficiency than a modern high-star-rating system. If you're heating a large home for long hours, the efficiency gain can shorten the payback period on a replacement considerably.
Our rule of thumb
If the repair costs more than half the price of a comparable new system and the unit is past two-thirds of its expected life, replacement usually wins. Below that, repair. We'll always give you both figures and let you decide.