Most furnace failures don’t happen because a system was “bad.”
They happen because small warnings were ignored for months.
I’ve pulled apart plenty of Goodman 96% AFUE furnaces that could’ve run another decade if someone had spent 10 minutes a month paying attention. Instead, dirt built up, airflow slipped, sensors got lazy — and by the time winter hit, the furnace was already in trouble.
100,000 BTU 96% AFUE Upflow/Horizontal Two Stage Goodman Gas Furnace - GR9T961004CN
This guide is about monthly furnace TLC — not a tune-up, not a teardown, just quick checks that:
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Catch problems early
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Keep efficiency honest
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Prevent emergency no-heat calls
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Protect the heat exchanger
If annual maintenance is your physical exam, monthly TLC is brushing your teeth.
🔁 Why Monthly Checks Matter on High-Efficiency Furnaces
A 96% AFUE furnace like the Goodman GR9T series runs tighter tolerances than old-school units.
That means:
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Airflow matters more
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Sensors get dirty faster
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Condensate systems must stay clear
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Small issues show up sooner
Monthly checks don’t replace annual service — they make annual service boring, which is exactly what you want.
⏱️ How Long This Takes (Honestly)
If everything is healthy:
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5–10 minutes per month
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No tools beyond a flashlight and your ears
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Zero technical skills required
You’re not fixing anything here — you’re noticing changes before they matter.
📅 The Monthly Furnace TLC Checklist (Jake’s Version)
Do these once a month during heating season. Pick a date you’ll remember — first weekend, thermostat battery day, whatever works.
🧼 1. Look at the Air Filter (Don’t Guess)
You don’t have to replace the filter every month — but you do have to look at it.
Monthly check:
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Pull the filter out
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Hold it up to light
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If you can’t see light → it’s done
Dirty filters cause:
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Overheating
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Limit switch trips
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Weak airflow
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Premature blower wear
This single check prevents more breakdowns than anything else on this list.
👂 2. Listen to the Furnace Start and Run
Your furnace talks to you — most people just don’t listen.
What “normal” sounds like:
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Smooth ignition
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Steady blower ramp-up
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No rattles, bangs, or whining
Red flags:
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Clicking or popping at startup
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Buzzing from the blower
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Sudden new noises
If it sounds different this month than last month, that’s your cue to investigate.
🔥 3. Watch the Flame (Quick Visual Check)
You’re not inspecting like a pro — just confirming nothing looks wrong.
Healthy flame:
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Mostly blue
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Stable and even
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No rolling or flickering
Unhealthy flame:
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Lazy yellow flames
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Flames lifting off burners
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Uneven ignition
If something looks off, stop there and call it in. Flame issues don’t fix themselves.
🌬️ 4. Check Airflow at a Few Registers
Airflow problems rarely start at the furnace — they show up in the house first.
Monthly walk-through:
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Feel airflow at several vents
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Note rooms that feel weaker than usual
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Make sure registers aren’t blocked
Sudden airflow changes often point to:
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Dirty filters
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Blower issues
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Duct obstructions
Catching this early protects the heat exchanger and blower motor.
💧 5. Peek at the Condensate Drain Area
High-efficiency furnaces make water — and water causes problems when ignored.
Monthly glance:
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No standing water
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No dripping or stains
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Drain line looks secure
Blocked drains cause:
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Pressure switch faults
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Random shutdowns
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Internal corrosion
This is one of those “five seconds now or five hours later” checks.
🧠 6. Check for Flash Codes or Warning Lights
Modern Goodman furnaces log complaints — even when they keep running.
What to do:
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Look at the control board sight glass
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Note any flashing codes during operation
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Compare to last month
Repeated warnings mean something is drifting out of spec — airflow, ignition, or sensors.
🌡️ 7. Confirm the Thermostat Is Behaving Normally
Thermostats cause more “furnace problems” than furnaces do.
Monthly check:
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Temperature matches how the house feels
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No short cycling
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No unexpected stage jumps
If the system seems to hit high fire too often, efficiency drops and wear increases.
🧯 8. Verify Safety Basics (Quick but Critical)
These aren’t furnace parts — but they matter just as much.
Once a month:
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Test carbon monoxide detectors
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Confirm nothing flammable is near the furnace
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Make sure intake/exhaust pipes aren’t blocked
Safety problems don’t give second chances.
📝 9. Make a One-Line Monthly Note
This sounds boring. It isn’t.
Write down:
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“All normal”
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Or “slight noise from blower”
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Or “filter replaced”
Patterns show up on paper long before they show up as breakdowns.
🚨 Monthly Red Flags You Should Never Ignore
Call a pro if you notice:
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Repeated shutdowns
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Burning smells
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Loud bangs or pops
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Water where it shouldn’t be
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CO detector alerts
Monthly TLC is about awareness — not bravery.
🧠 How Monthly TLC Saves You Money (Real Talk)
Here’s what monthly checks prevent:
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Emergency service calls
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Heat exchanger stress
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Blower motor burnout
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Sensor failures
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Winter downtime
A furnace that’s watched monthly almost never surprises you.
🔄 Monthly TLC vs Annual Tune-Up (Know the Difference)
Monthly TLC:
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Observation
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Light checks
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Early warnings
Annual tune-up:
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Cleaning
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Measurements
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Adjustments
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Combustion testing
Do both, and your furnace becomes boring — in the best way possible.
🔗 Verified External Resources
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Goodman Gas Furnace Overview:
https://www.goodmanmfg.com/products/gas-furnaces -
Furnace Filter Basics (EPA):
https://www.epa.gov/indoor-air-quality-iaq -
Carbon Monoxide Safety (CDC):
https://www.cdc.gov/carbon-monoxide/about/index.html -
High-Efficiency Furnace Operation (Energy.gov):
https://www.energy.gov/energysaver/furnaces-and-boilers
🔚 Jake’s Final Word
Monthly furnace TLC isn’t about being technical.
It’s about not being surprised.
Five minutes a month keeps small problems small, protects the parts that matter most, and turns winter from a gamble into a non-event.
Do the checks. Write the note. Let your furnace do its job.
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In the next topic we will know more about: Goodman Furnace Filter Mastery: Which Filters, When to Replace, and Why It Matters







