Should I repair or replace my furnace?

Short answer: Repair a furnace that's under roughly 12 years old, has a minor, isolated fault, and a clean safety record. Replace when it's 15+ years old, the repair costs a large share of a new unit, it keeps breaking down, or there's any heat-exchanger crack or carbon-monoxide concern. Safety always overrides cost math.

The factors that decide it

There's no single rule, but five factors settle most cases:

• Age — furnaces typically last 15–20 years; past 15, replacement gets more compelling.
• Repair cost vs. replacement — a common guideline: if a repair approaches roughly half the cost of a new furnace, replace.
• Repair frequency — repeated breakdowns signal a unit at end of life.
• Efficiency — an old mid-efficiency furnace wastes gas a 96%+ AFUE unit would save every winter.
• Safety — a cracked heat exchanger or CO risk is a replace-now situation, full stop.

When repair is the smart money

A relatively young furnace with a failed igniter, flame sensor, or capacitor is usually worth fixing — those are routine parts, not a death sentence. If it's heated reliably and a technician confirms the heat exchanger is sound, repair and keep it running. Don't let a pushy upsell talk you into replacing a healthy furnace.

When replacement wins

If you're facing a major component failure (heat exchanger, control board on a very old unit) on a furnace past 15 years, the repair often just delays the inevitable while you keep paying high gas bills. This is also the natural moment to compare alternatives: a heat pump or hybrid can replace the furnace's role and your AC at once, with rebates in play. See real pricing in furnace cost in Ontario.

The misconception: "always repair to save money"

Repeatedly repairing an old, inefficient furnace can cost more over a few winters than a new high-efficiency unit — in parts, service calls, and wasted fuel — while still leaving you with an end-of-life system. The cheapest today isn't always the cheapest over three years. A straight diagnosis, not a default to "repair," gives you the real picture.

Get an honest diagnosis

Have a licensed technician diagnose the fault, check the heat exchanger, and quote both the repair and a replacement so you can compare with real numbers. Energy Clean offers 24-hour heating service across the GTA and gives you the straight call — repair when it's right, replace only when it's warranted. If you've been told to replace and aren't sure, get a free second opinion.