Every HVAC company has an incentive to tell you to replace. A replacement is a bigger job than a repair, so you should treat “you need a new one” with the scepticism you would apply to any expensive recommendation from the person selling it.
So here is the arithmetic, laid out, so you can run it yourself and check ours.
The rules of thumb, and where they break
The 50% rule. If a repair costs more than half of a replacement, replace. Reasonable, and it is the one most people have heard.
The age × cost rule. Multiply the equipment’s age in years by the repair cost. If that exceeds the replacement cost, replace. A 20-year-old furnace needing a $600 repair scores 12,000 — well past most replacement costs. A 6-year-old furnace needing the same repair scores 3,600, and you fix it.
Both are useful and both miss things. What they miss:
The failure was not the first one. Two repairs in one season on the same unit changes the picture regardless of what either one cost. You are not buying a fix, you are buying a few more months.
Parts availability. For equipment past roughly twenty years, parts get scarce and expensive. A cheap repair that takes three weeks to source in January is not cheap.
What else the replacement changes. This is the one the rules of thumb ignore entirely, and it is often the deciding factor.
What replacement changes that repair does not
You can add cooling. If you are replacing heating equipment anyway, a heat pump gives you air conditioning as part of the same project rather than as a separate one later. For a lot of Lower Mainland houses this is the actual reason to replace — summers here are not what they were.
Efficiency. A twenty-year-old furnace is meaningfully less efficient than a current one. How much that is worth depends on your gas rate and how much you run it; it is real, but it is rarely enough on its own to justify replacing working equipment.
Rebates only apply to replacement. There are no incentives for repairing a furnace. This should not drive the decision — chasing an incentive into the wrong equipment is a real failure mode — but it belongs in the arithmetic. Our rebate tool will tell you which programs your situation points at.
Financing spreads it. A repair is money now. A replacement can be financed, which for some households changes a $600 problem-this-month into a manageable monthly figure with better equipment attached. The financing terms are worth looking at before deciding you cannot afford the replacement.
When repair is clearly right
We tell people to repair regularly, and here is when:
- The unit is under about twelve years old and this is its first significant fault.
- It is a cheap consumable part — igniter, flame sensor, capacitor, thermocouple. These are wear items, not symptoms of a dying furnace.
- You are moving within a couple of years. You will not recover a replacement in resale, and the next owner may want something different anyway.
- It is mid-January and the house is cold. Get it running. Have the replacement conversation in April when you can compare quotes properly instead of deciding under pressure.
That last one matters more than people realise. Nobody makes a good equipment decision at 9pm on a cold Tuesday.
When replacement is clearly right
- Cracked heat exchanger. This is not a judgement call. It is a carbon monoxide risk and the unit gets shut down. Anyone offering to repair one should be shown the door.
- Repeated failures across a season.
- Past twenty years with an expensive fault.
- The refrigerant is R-22, on the cooling side. Phased out, expensive, and a system leaking it is on borrowed time.
- It never heated the house properly. If it was undersized or the ductwork was wrong from the start, repairing it just restores an unsatisfactory baseline.
The question to ask any contractor
“What specifically failed, and what is the condition of the rest of the unit?”
A good answer names the part, explains why it went, and gives you an honest read on the heat exchanger, the blower motor and the control board. A vague answer that moves straight to a replacement quote is telling you something.
Also worth asking: “If this were your house, what would you do?” The pause before the answer is informative.
What we do
We tell you when the repair is the better value, and we put the reasoning in writing. That has been the approach since 1989 and it is not principled so much as practical — this is a business built on people ringing us again in eight years, and on their neighbours ringing us.
If your furnace is misbehaving right now, the ten-minute checklist is worth working through first; a fair share of no-heat calls turn out to be a setting or a filter. If it is beyond that, we do repair and replacement across the Lower Mainland and we will tell you which one you actually need.