The Quick Decision Framework
Usually repair if:
- Furnace is under 10 years old
- First significant repair
- Repair cost is under $500
Usually replace if:
- Furnace is over 15 years old
- Heat exchanger is cracked
- Multiple repairs in past 2 years
- Repair exceeds 50% of replacement cost
But there's more to consider.
Repairs That Are Usually Worth It
Ignitor Replacement
Cost: $150-300 Worth it? Yes, almost always
Ignitors are wear items. They fail every 5-10 years. This is like changing brake pads — normal maintenance.
Flame Sensor Cleaning/Replacement
Cost: $100-200 Worth it? Yes
Flame sensors get dirty. Cleaning is cheap. Replacement is still affordable.
Thermostat
Cost: $100-300 Worth it? Yes
If the furnace itself is fine, a new thermostat is an easy fix.
Blower Motor
Cost: $400-700 Worth it? Usually, if furnace is under 12 years
Blower motors fail occasionally. If the rest of the furnace is healthy, this repair is reasonable.
Inducer Motor
Cost: $400-800 Worth it? Depends on age
In a furnace under 10 years? Yes. In a 15-year-old furnace? Getting questionable.
Repairs That Often Mean Replacement
Heat Exchanger
Cost: $1,500-3,000+ Worth it? Usually no
A cracked heat exchanger is serious — it can leak carbon monoxide. Repair cost often approaches or exceeds replacement cost for an older furnace.
If your heat exchanger is cracked and furnace is over 12 years: Replace.
Control Board
Cost: $500-1,200 Worth it? Depends heavily on age
On a 5-year-old furnace? Probably yes. On a 15-year-old furnace? Probably no.
Gas Valve
Cost: $400-800 Worth it? Usually, but consider age
Similar to control board — worth it on newer units, questionable on older ones.
The Math: Repair vs Replace Calculation
Method 1: The 50% Rule If repair costs more than 50% of replacement, replace.
Example: New furnace installed = $5,000 50% threshold = $2,500 Repair quote = $1,800 → Repair makes sense mathematically
Method 2: The 5000 Rule Multiply unit age by repair cost. Over $5,000? Replace.
Example: 14-year-old furnace, $500 repair 14 × 500 = $7,000 → Consider replacing
Method 3: Remaining Life Calculation Estimate remaining life. Divide replacement cost by remaining years. Compare to repair + ongoing costs.
Example:
- 13-year-old furnace (maybe 5 years left)
- New furnace: $5,000 ÷ 18 years = $278/year
- Repair $800 now + likely repairs over 5 years
- Which costs less over time?
Beyond the Math: Other Factors
Efficiency Gains
A 15-year-old furnace might be 80% efficient. New furnaces are 95%+. The gas savings add up.
In Vancouver's mild climate, savings are moderate — but still meaningful over 15+ years.
Reliability Value
An old, repaired furnace might fail again — possibly during the coldest week of winter. A new furnace comes with warranty and peace of mind.
Home Sale Timing
Selling soon? Buyers prefer modern equipment. A new furnace can help your home sell.
Rebates and Incentives
Check current rebates:
- CleanBC rebates for heat pumps
- FortisBC rebates for high-efficiency gas furnaces
- Manufacturer promotions
These can change the math significantly.
When to Upgrade to Heat Pump
If you're replacing anyway, consider a heat pump:
Pros:
- Heating and cooling in one system
- Higher efficiency
- Significant rebates available in BC
- Works well in Vancouver's mild climate
Cons:
- Higher upfront cost
- May need electrical upgrade
- Backup heat recommended for coldest days
For Vancouver homes, heat pumps often make sense — especially with current rebates.
Making the Decision
Get multiple quotes for both repair and replacement. A good HVAC company will give you honest advice — not just push the expensive option.
Ask:
- What's the realistic remaining life?
- What other repairs might be coming?
- What's included in a new install (warranty, thermostat, etc.)?
Then decide based on math, reliability, and your plans for the home.