FurnaceBuying Guide2025-10-22
High-Efficiency Furnaces and AFUE Explained
AFUE measures how much fuel becomes heat — here's what the numbers mean for your bills.
When shopping for a furnace, AFUE is the key efficiency number. Understanding it helps you balance upfront cost against long-term savings.
What AFUE means
Annual Fuel Utilization Efficiency is the percentage of fuel converted to heat. A 96% AFUE furnace turns 96% of the gas into usable heat; older units may be 60–80%.
Is high-efficiency worth it?
High-efficiency (90%+ AFUE) condensing furnaces cost more upfront but cut gas use significantly and qualify for rebates, paying back over time in a climate like BC's.
Key takeaways
- Look for 95%+ AFUE for best savings
- High-efficiency models need condensate drainage
- Check rebate eligibility for efficient units
- Pair efficiency with correct sizing
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