How to Shut It Down the Right Way (and Avoid Springtime Surprises)
Electric furnaces don’t get much attention in the off-season—and honestly, that’s fine.
What’s not fine is flipping the thermostat off in spring and forgetting the system exists until the first cold snap hits again.
Goodman 68,240 BTU 20 kW Electric Furnace with 2,000 CFM Airflow - MBVK20DP1X00, HKTAD201
I’ve seen too many electric furnaces:
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Full of dust
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Rusted at terminals
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Infested by critters
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Or tripping breakers on the first fall startup
All because the shutdown was rushed or skipped entirely.
This guide walks you through how to properly turn off and winterize an electric furnace, so it’s protected, clean, and ready when heating season comes back around.
🧠 What “Winterizing” Means for an Electric Furnace
Let’s clear something up.
Winterizing an electric furnace doesn’t mean draining pipes or adding antifreeze like you would with outdoor equipment.
Instead, it means:
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Shutting the system down safely
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Preventing dust, moisture, and corrosion
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Protecting electrical components
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Preserving airflow and wiring
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Making the next startup smooth and predictable
Think of it as putting the furnace to sleep properly, not just turning it off.
🔒 Step 1: Switch the Thermostat Correctly
Before touching breakers or panels, start at the thermostat.
What to do
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Set the system to OFF (not just “Heat Off”)
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Disable emergency heat if applicable
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Replace thermostat batteries if it uses them
Why this matters
Leaving the thermostat active can:
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Trigger short cycles
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Confuse smart thermostats
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Cause accidental fan operation
Thermostat best practices:
👉 ENERGY STAR – Thermostat Use & Settings
https://www.energystar.gov/products/smart_thermostats
⚡ Step 2: Power Down at the Breaker (Safely)
Once the thermostat is off:
Proper shutdown steps
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Locate all breakers feeding the furnace
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Turn them fully OFF
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Label the breaker if it’s not clearly marked
Some electric furnaces use multiple breakers. Missing one leaves parts of the system energized.
Mike’s rule
If even one breaker stays on, assume the furnace is live.
Electrical safety reference:
👉 Electrical Safety Foundation International (ESFI)
https://www.esfi.org/home-electrical-safety/
🧹 Step 3: Clean Before You Walk Away
This is the most skipped step—and the most important.
What to clean
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Replace or remove the air filter
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Vacuum loose dust inside the cabinet
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Wipe flat metal surfaces
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Clear debris near wiring and heat strips
Why now?
Dust that sits all summer:
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Absorbs moisture
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Promotes corrosion
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Attracts insects
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Hardens onto components
A 10-minute cleanup now saves headaches later.
Air filter & dust guidance:
👉 EPA – Air Filters & Indoor Air Quality
https://www.epa.gov/indoor-air-quality-iaq
🌬️ Step 4: Protect the Airflow Path
Your furnace doesn’t just sit idle—it shares space with your home’s air.
Do this
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Remove and discard old filters
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Leave filter slot empty or insert a clean filter
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Make sure return grilles aren’t blocked
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Close supply vents only if recommended by your HVAC design
Never seal off the furnace cabinet completely—air still needs to move around it.
💧 Step 5: Control Moisture & Humidity
Summer humidity is rough on electric systems.
Moisture risks include
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Corrosion on terminals
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Rust on cabinets
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Oxidation on control boards
Smart prevention steps
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Keep basement humidity between 30–50%
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Use a dehumidifier if needed
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Fix nearby plumbing leaks
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Keep floor drains clear
Humidity & indoor air guidance:
👉 ENERGY STAR – Indoor Humidity
https://www.energystar.gov/newhomes/features-benefits/indoor-air-quality-features
🐭 Step 6: Keep Critters Out (Seriously)
You’d be surprised how often I open furnaces in fall and find:
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Nesting material
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Chewed wiring
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Debris in blower housings
Prevention tips
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Seal obvious gaps around duct penetrations
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Keep surrounding area clean
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Avoid storing cardboard or insulation nearby
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Do NOT stuff rags or foam inside the cabinet
The furnace cabinet isn’t a storage box—it’s a mechanical system.
📦 Step 7: What Not to Do During Shutdown
Let’s talk about common mistakes.
❌ Don’t do this
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Don’t leave a dirty filter installed
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Don’t spray cleaners or moisture inside
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Don’t disconnect wires “just in case”
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Don’t cover vents with plastic
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Don’t ignore breaker labeling
Electric furnaces fail more often from human “fixes” than from sitting idle.
📝 Step 8: Leave Yourself a Startup Note
This sounds simple, but it works.
What to note
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Date of shutdown
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Filter size needed
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Any issues noticed last season
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Which breakers power the furnace
Tape it inside the access panel or keep it with home maintenance records.
Your future self will thank you.
🔄 Step 9: What to Do Before Fall Startup
When heating season returns:
Quick reactivation checklist
✔ Install a fresh filter
✔ Restore all breakers
✔ Set thermostat to Heat
✔ Listen for abnormal sounds
✔ Monitor first heating cycle
Startup guidance:
👉 U.S. Department of Energy – Heating System Maintenance
https://www.energy.gov/energysaver/home-heating-systems
📅 Ideal Seasonal Timeline
Late Spring
✔ Shut down system
✔ Clean cabinet & filter area
Summer
✔ Maintain humidity
✔ Keep area clean
Early Fall
✔ Install fresh filter
✔ Power up & test
📋 Seasonal Swap Quick Checklist
✔ Thermostat OFF
✔ Breakers OFF
✔ Filter removed or replaced
✔ Cabinet cleaned
✔ Moisture controlled
✔ Area sealed & cleared
✔ Notes left for startup
Print this. Use it every year.
🧠 Final Word from Mike
Electric furnaces don’t need pampering—but they do need respect during downtime.
A clean, dry, powered-down furnace:
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Starts easier
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Runs more efficiently
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Lasts longer
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Costs less to maintain
Think of seasonal shutdown as protective storage, not neglect.
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In the next topic we will know more about: Smart Thermostat Integration & Maintenance: Keep the Goodman in Sync
