Quick answer
The $5,000 rule
Age in years × repair cost. Below $5,000, lean repair. Above $5,000, lean replace.
The 50% rule
If a repair costs more than half the price of new equipment, replace.
Typical lifespans in Ottawa
Gas furnaces 15–20 years, central AC 12–15 years, heat pumps 12–15 years.
Always replace for safety
A cracked heat exchanger or repeated carbon monoxide concerns.
R-22 systems
A refrigerant leak on an R-22 AC is almost always a replace.
Typical repair costs
Furnace $150 – $900, AC $150 – $1,200.
How the age × repair cost rule works
The rule balances two things: how much life the equipment has left and how much you are putting into it. A young system with a big repair is still a good bet. An old system with even a modest repair is often throwing good money after bad.
| Example | Age × cost | Verdict |
|---|---|---|
| 6-year-old AC, $350 capacitor and contactor | 6 × $350 = $2,100 | Repair |
| 9-year-old furnace, $700 igniter and flame sensor | 9 × $700 = $6,300 | Borderline: repair if maintained and reliable |
| 16-year-old furnace, $1,200 inducer motor | 16 × $1,200 = $19,200 | Replace |
| 13-year-old AC, $2,500 compressor | 13 × $2,500 = $32,500 | Replace |
| 4-year-old AC, $2,500 compressor under parts warranty | Labour only | Repair |
Treat the rule as a starting point, not a verdict. Your repair history, the efficiency of the old unit and the safety findings can tip the decision either way.
Repair or replace by age
| Equipment age | Furnace | Central AC |
|---|---|---|
| 0–8 years | Repair almost anything. Check parts warranty first. | Repair almost anything, including a compressor under warranty. |
| 8–12 years | Repair most items. Replace if the heat exchanger or several major parts fail. | Repair minor items. Think hard about a compressor or coil. |
| 12–15 years | Repair small, cheap items only. Start budgeting. | Lean replace for anything beyond a capacitor or contactor. |
| 15+ years | Lean replace, especially for mid-efficiency (80% AFUE) furnaces. | Replace for most repairs, and always for an R-22 leak. |
Ottawa’s long heating season works furnaces hard, so a 15-year-old furnace here has done more work than the same unit in a milder climate. Our furnace lifespan guide explains what shortens and extends that life.
When to replace no matter what the math says
Safety problems
A cracked or rusted-through heat exchanger can let combustion gases, including carbon monoxide, mix with the air in your home. Replacing a heat exchanger on an older furnace is rarely worth it. If a technician red-tags a furnace under TSSA rules, it cannot be used until the hazard is fixed. See our furnace carbon monoxide safety guide for warning signs.
R-22 air conditioners
R-22 refrigerant has been phased out in Canada. Remaining supply is limited and expensive, and no new equipment uses it. If an R-22 system has a leak or a failed compressor, recharging it rarely makes sense. Newer systems use R-410A, and the latest equipment is moving to R-454B and R-32.
A failed compressor on an older AC
A compressor replacement typically costs $1,800 – $3,500. On an AC older than about 10 years, that money is usually better put toward a new, matched system with a fresh warranty. A new compressor in an old system can also run into problems with a mismatched, worn indoor coil.
Repeated breakdowns
If you have paid for two or more significant repairs in two years, the next one is likely around the corner. Patterns matter more than any single bill.
Efficiency: what an old system really costs you
Efficiency gains can make replacement pay back faster than you expect, especially on furnaces.
Furnaces
A 20-year-old mid-efficiency furnace is about 80% AFUE, so 20 cents of every gas dollar goes up the chimney. A new furnace in Canada must be at least 95% AFUE, and most are 96–98%. That cuts wasted fuel by roughly three-quarters.
Air conditioners
A 15-year-old AC may be around 10–13 SEER, and it has likely lost some efficiency to age and wear. New central air is rated in SEER2 and is considerably more efficient, with variable-speed models removing more humidity on muggy days.
Heat pumps
If your AC is due, a cold-climate heat pump can replace it and also cover much of your heating. Read do heat pumps work in Ottawa winters to see if it fits.
Our SEER2, AFUE and HSPF2 guide explains the ratings in plain terms.
What repair and replacement cost in Ottawa
| Item | Typical range |
|---|---|
| Furnace repair (most common repairs) | $150 – $900 |
| Major furnace parts (blower motor, control board, inducer) | $600 – $2,000 |
| AC repair (most common repairs) | $150 – $1,200 |
| AC compressor replacement | $1,800 – $3,500 |
| High-efficiency gas furnace replacement | $4,500 – $8,500 (variable-speed/modulating up to ~$10,500) |
| Central air conditioner replacement | $4,000 – $8,000 |
| Furnace + AC combo replacement | $8,000 – $15,000 |
| Ducted cold-climate heat pump (existing ducts) | $9,000 – $18,000 |
These are typical installed ranges before rebates, not quotes. The final price depends on the home, the equipment and the venting and ductwork. Oria gives free quotes on any equipment purchase, and financing is available from $49/month on approved credit through our financing options.
Should you replace the furnace and AC together?
If one is failing and the other is more than about 10–12 years old, replacing both together often makes sense. You get matched equipment designed to work together, one installation visit, one set of warranties and usually a lower combined price than two separate jobs. If the other system is young and healthy, there is no need to replace it.
Kenneth D. described the kind of advice you should expect: “They are quick to respond and very knowledgeable, offering creative and reasonable solutions.” A good technician will show you the failed part, give you the repair price and the replacement price, and let you decide.
Questions to ask before you decide
- What exactly failed, and can you show me the part?
- Is the part covered by the manufacturer’s parts warranty? Was the unit registered?
- Did you find any other worn parts that are likely to fail soon?
- What is the efficiency of my current unit, and what would a new one save?
- Is my current system sized correctly for the house, or was it oversized?
- Are there rebates available right now for a replacement? Oria checks current programs on our HVAC rebates page.
Get an honest repair-or-replace opinion
Oria has served Ottawa since 2014 and repairs every make and model, so we have no reason to push a replacement you do not need. Book air conditioning repair or furnace service, and if replacement is the smarter move, we will quote it with a free quote. Call (613) 866-1869.
Frequently Asked Questions
What is the $5,000 rule for HVAC repair?
Multiply the age of your furnace or air conditioner by the repair cost. If the result is under $5,000, repairing usually makes sense. If it is over $5,000, replacement is usually the better investment. For example, a $400 repair on a 7-year-old AC equals $2,800, so repair it. A $900 repair on a 16-year-old furnace equals $14,400, so replace it.
Is it worth repairing a 15-year-old furnace?
Only for small, inexpensive repairs such as an igniter, flame sensor or capacitor. Ottawa furnaces typically last 15–20 years, so a 15-year-old unit is near the end of its life. For major parts, a cracked heat exchanger or repeated breakdowns, replacing it with a 96–98% AFUE furnace is usually smarter. A typical replacement costs $4,500 – $8,500 installed.
Should I replace my AC if it uses R-22?
Usually, yes, if it needs refrigerant or a major repair. R-22 has been phased out in Canada, so remaining supply is scarce and expensive, and no new systems use it. A leak or compressor failure on an R-22 system is rarely worth fixing. A new central air conditioner typically costs $4,000 – $8,000 installed in Ottawa.
Is replacing an AC compressor worth it?
A compressor replacement typically costs $1,800 – $3,500 in Ottawa. It is worth it on a fairly new AC, especially when the compressor is still under the manufacturer’s parts warranty and you only pay labour. On a system older than about 10 years, putting that money toward a new, matched AC with a fresh warranty is usually the better choice.
How long do furnaces and air conditioners last in Ottawa?
A well-maintained gas furnace typically lasts 15–20 years in Ottawa, while central air conditioners and heat pumps usually last 12–15 years. Lifespan depends on installation quality, sizing, filter changes and yearly maintenance. Equipment that was oversized or rarely serviced often fails earlier, while a regularly tuned system can reach the upper end of these ranges.
Should I replace my furnace and AC at the same time?
It often makes sense if one has failed and the other is more than 10–12 years old. Matched equipment works better together, and one installation usually costs less than two. A furnace and AC combo typically costs $8,000 – $15,000 installed in Ottawa. If the other unit is young and working well, replacing only the failed system is fine.
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