80% vs 90% Furnace — What’s the REAL Difference (and What Repairs can Cost You)

What’s the difference between an 80% and a 90% furnace? And why can replacing all the parts inside one cost nearly $9,000? In this video, Yarbrough & Sons Heating, Cooling & Plumbing breaks down two furnaces that look similar—but perform very differently. We’ll show you: ✅ How efficiency ratings actually work (80% vs 90%) ✅ The key parts that make high-efficiency furnaces more expensive ✅ Common repair costs for motors, gas valves, igniters, and more ✅ When it’s better to replace your system instead of repairing it If you’re wondering whether a high-efficiency furnace is worth it—or which one makes sense for your home—this is your complete guide. 🔥 Get an instant estimate for a new system in under 45 seconds: https://estimate.yarbroughandsons.com 00:00 - Introduction to 80% vs. 90% Furnaces 00:21 - Understanding Furnace Efficiency Ratings 00:51 - Upflow vs. Downflow Furnace Explained 01:13 - Disassembling Both Furnaces 01:48 - Part Comparison: Condensate Trap 02:43 - Part Comparison: Control Board & Door Switch 04:52 - Part Comparison: Transformer 06:05 - Part Comparison: Blower Assembly & Motor 08:44 - Part Comparison: Gas Valve 09:48 - Part Comparison: Igniter 11:17 - Part Comparison: Limit & Rollout Switches 12:46 - Service & Estimate Information 13:22 - Part Comparison: Pressure Switches 14:06 - Part Comparison: Flame Sensors 15:46 - Part Comparison: Inducer Motors 17:58 - Part Comparison: Burner Assembly 18:54 - Part Comparison: Heat Exchangers 21:11 - The Importance of Maintenance & Air Filters 23:30 - Why an 80% Furnace Might Be Better for Attics 24:44 - Cost to Replace a Heat Exchanger 26:36 - Final Thoughts & Summary