October in Minnesota means one thing for homeowners: it's time to make sure your furnace is ready. A few hours of preparation now can prevent a breakdown at -20°F in January. Here are the 10 most important things to do before heating season starts.
1. Replace Your Air Filter
Start the heating season with a fresh filter. A clean filter ensures maximum airflow, prevents overheating, and gives you a clean baseline to measure filter life through winter. Standard 1-inch pleated filters (MERV 8): replace every 60–90 days. 4-inch media filters: replace every 6–12 months.
2. Test Your Furnace Before You Need It
Turn your thermostat to heat mode and set it 5 degrees above room temperature. Let it run through a complete cycle. Listen for any new noises; check that heat reaches all vents; verify the blower starts properly. Do this in September or early October — not when it's already cold and you're desperate for heat.
3. Check Your CO Detectors
Carbon monoxide detectors should be within 10 feet of each bedroom and near the furnace. Test them now (press the test button), replace batteries, and replace any detector over 5–7 years old. CO detectors are your safety net against heat exchanger cracks — the risk increases as furnaces age.
4. Clear the Area Around Your Furnace
Furnaces need clearance from combustibles — typically 30 inches on the service side, 6 inches on other sides (check your manual for specifics). Summer storage has a way of creeping toward the furnace. Clear it out before heating season.
5. Check Vents and Registers Throughout the House
Walk every room and confirm all supply and return vents are open and unobstructed. Furniture gets moved in summer; rugs get shifted. Closed or blocked vents create pressure imbalances that stress your furnace and create cold spots. Every vent should be open unless you have a zoning system.
6. Inspect the Flue Pipe
For high-efficiency furnaces (PVC venting): check both the intake and exhaust terminations on the outside of your home. Verify they're clear of debris, bird nests, or damage from lawn equipment. For older furnaces with metal flues: check for rust, gaps, or disconnections. A disconnected flue is a CO emergency.
7. Flush the Condensate Drain (High-Efficiency Furnaces)
90%+ AFUE furnaces produce condensate water. The drain line can develop algae buildup over summer. Pour a cup of water into the condensate trap and verify it drains freely. If it backs up, the furnace will shut down on a safety fault mid-winter. Clear it now with a shop vac or diluted bleach solution.
8. Check Your Thermostat
Switch from cooling to heating mode. Verify the thermostat is reading correct room temperature. If you have a programmable or smart thermostat, update your heating schedule. Replace batteries in battery-powered thermostats — a dead thermostat battery is a surprisingly common "furnace problem" service call.
9. Schedule a Professional Tune-Up
Annual professional maintenance is the single best thing you can do for furnace longevity. HVAC techs are less busy in September–October than November–January. A tune-up covers heat exchanger inspection, burner cleaning, ignitor testing, gas pressure verification, and safety control testing — things you can't DIY. Cost: $80–$150. What it prevents: a $500–$2,000 emergency repair or early replacement.
10. Assess Your Furnace's Age and Condition
Fall is the right time to make honest decisions about aging equipment. Is your furnace over 15 years old? Has it needed repairs in the last year or two? Are your gas bills trending upward? If the answer is yes to two or more of these, plan a proactive replacement before you're in an emergency in January. Furnace Direct offers same-day delivery — call (888) 762-1334 for current pricing on Goodman furnaces.
When should I turn my furnace on for the first time in fall?
Test your furnace for the first time in September or early October — before you actually need it. This gives you time to address any problems that show up (an ignitor that failed over summer, a clogged filter, a dead thermostat battery) without being in an emergency situation. The first time you need your furnace should never be the first time you've tested it that season.
Why does my furnace smell when I first turn it on in fall?
A burning dust smell when the furnace first runs in fall is normal — dust that settled on the heat exchanger and burners over summer is burning off. This smell should dissipate after 1–3 heating cycles. A persistent burning smell, a chemical smell, or a gas smell are different situations: persistent burning suggests a clogged filter or motor issue; gas smell means turn off the furnace and call your gas utility immediately.
How do I know if my furnace is ready for a Minnesota winter?
After working through this checklist, your furnace is ready if: it starts and runs through complete cycles without issues, the burner flame is blue and steady, no unusual noises have developed, the filter is clean, CO detectors are working, and venting is clear. If you're over 15 years old and haven't had a professional tune-up in 2+ years, schedule that inspection even if everything seems fine — professional eyes catch problems homeowners can't.
What's the most important fall furnace maintenance task?
Filter replacement and the professional tune-up are equally important and complementary. The filter you can do yourself in 5 minutes; the professional tune-up catches the things you can't see — heat exchanger cracks, gas pressure issues, ignitor wear. Both together give you the best chance of a trouble-free Minnesota heating season.
Is Your Furnace Ready for Winter? Get a Fast Quote
If your furnace is 15+ years old, plan ahead. Same-day delivery, factory-direct pricing.
📞 (888) 762-1334 🧮 Size Your FurnaceGet wholesale pricing on a new system.
Tell us a little about your home and what you're replacing. We'll send real numbers on a Goodman 96% AFUE setup — shipped direct to your door anywhere in the lower 48. No contractor markup, no obligation.