High-efficiency furnaces like the Goodman 96% AFUE two-stage gas furnace are designed to work smarter, not harder. But here’s the truth most homeowners don’t hear enough: even the best furnace won’t stay efficient on autopilot.
I’ve seen furnaces lose performance not because they were “bad units,” but because simple seasonal maintenance got skipped. The good news? You don’t need to be an HVAC tech to keep your system running strong. You just need the right plan, broken down by season.
This guide walks you through exactly what to do, when to do it, and why it matters—so your Goodman furnace stays efficient, reliable, and ready no matter what the weather throws at it.
🧠 Why Seasonal Maintenance Matters for a 96% AFUE Furnace
A 96% AFUE furnace means 96 cents of every dollar you spend on gas becomes usable heat. That efficiency depends on:
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Clean airflow
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Proper combustion
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A healthy condensate system
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Smart staging and blower operation
When even one of those is neglected, efficiency drops—and parts wear out faster.
Seasonal maintenance isn’t about overdoing it. It’s about doing the right things at the right time.
🍂 Fall: Pre-Heating Season Readiness (Your Most Important Check)
Fall is your furnace’s “pre-game warm-up.” Skipping these steps is the #1 reason homeowners experience mid-winter breakdowns.
✅ 1. Replace or Upgrade the Air Filter
A dirty filter restricts airflow, forcing the blower motor to work harder and disrupting two-stage performance.
Samantha tip:
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Most homes need a new filter every 1–3 months
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High-efficiency furnaces perform best with MERV 8–11 filters (higher isn’t always better)
👉 Learn more about proper filter selection from Energy.gov:
https://www.energy.gov/energysaver/maintaining-your-heating-system
🔍 2. Inspect Intake & Exhaust PVC Pipes
Your Goodman furnace uses sealed combustion with PVC venting.
Check for:
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Leaves, nests, or debris
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Sagging or disconnected joints
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Frost damage in colder climates
Blocked venting = poor combustion + safety shutdowns.
💧 3. Flush the Condensate Drain Line
High-efficiency furnaces create condensation. If the drain clogs, the furnace will shut itself off to prevent water damage.
What to do:
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Pour warm water through the drain
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Add a small amount of vinegar to prevent buildup
🔥 4. Test the Thermostat & Staging
Your two-stage furnace should:
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Start in low stage for steady comfort
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Ramp up only when needed
If it always runs full blast, that’s a sign of airflow or control issues.
🛠️ 5. Schedule a Professional Annual Inspection
Even DIY-savvy homeowners should get one pro check per year.
A technician can:
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Inspect the heat exchanger
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Verify gas pressure
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Test safety switches
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Confirm combustion efficiency
👉 Why annual inspections matter (ASHRAE):
https://www.ashrae.org/technical-resources
❄️ Winter: In-Season Performance & Safety Checks
Once winter hits, your focus shifts from prep to monitoring and protection.
🌡️ 1. Watch for Efficiency Red Flags
Pay attention to:
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Longer run times than usual
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Uneven heating
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Sudden utility bill spikes
These are early warning signs—not annoyances to ignore.
🔊 2. Listen to Your Furnace
A healthy Goodman furnace sounds smooth and consistent.
Call for service if you hear:
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Rattling or banging
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Whistling airflow
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Repeated clicking or short cycling
🚫 3. Keep Supply & Return Vents Clear
Blocked vents reduce airflow and strain the blower.
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Don’t close too many registers
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Keep furniture and rugs clear
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Check basement and spare rooms
👉 Airflow basics explained by HVAC.com:
https://www.hvac.com/expert-advice/common-hvac-problems/
🧯 4. Test Carbon Monoxide Detectors
This is non-negotiable.
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Test monthly in winter
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Replace batteries annually
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Detectors should be near bedrooms and the furnace area
👉 CO safety guidance from CDC:
https://www.cdc.gov/carbon-monoxide/about/index.html
🌸 Spring: Post-Season Inspection & Light Maintenance
Spring is where smart homeowners prevent next winter’s problems.
🧹 1. Clean Around the Furnace Cabinet
Dust, pet hair, and storage clutter restrict airflow and attract moisture.
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Vacuum around the base
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Wipe exterior panels
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Remove stored items nearby
🧾 2. Review Your Winter Notes
Did you notice:
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Cold rooms?
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Strange noises?
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Higher bills?
Write it down now while it’s fresh. This helps technicians diagnose issues faster later.
🔍 3. Check the Drain Line Again
Spring humidity can increase biological growth in condensate lines. A quick flush now avoids summer clogs.
☀️ Summer: Off-Season Protection & Planning
Even when it’s not running, your furnace still benefits from attention.
🛑 1. Power Protection Check
If your area gets summer storms:
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Consider a surge protector
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Check grounding and electrical connections
Power surges quietly damage control boards.
📅 2. Plan Ahead for Fall Service
Booking early:
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Saves money
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Gets better appointment times
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Avoids emergency pricing
🗂️ 3. Maintain a Furnace Maintenance Log
Track:
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Filter changes
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Service dates
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Observed issues
This helps with:
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Warranty claims
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Resale value
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Long-term reliability
👉 Furnace care best practices from This Old House:
https://www.thisoldhouse.com/heating-cooling
⚖️ What You Can DIY vs. When to Call a Pro
✔️ Homeowner-Friendly Tasks
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Filter changes
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Vent inspection
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Drain line flushing
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Visual inspections
❌ Pro-Only Tasks
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Heat exchanger inspection
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Gas valve adjustment
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Combustion analysis
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Control board diagnostics
When in doubt, safety always wins.
🏁 Final Thoughts: Small Habits, Big Comfort
Your Goodman 96% AFUE furnace is built for efficiency, comfort, and longevity—but it relies on you to meet it halfway.
Seasonal maintenance isn’t about perfection. It’s about:
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Catching small issues early
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Protecting efficiency
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Staying warm without surprises
Stick to this Warm & Wise plan, and your furnace won’t just heat your home—it’ll earn its keep year after year.
