Short answer: Change your filter every 1–3 months, keep vents clear, and test your CO detectors — that’s the homeowner half. Once a year, get a pro tune-up ($109) to check the heat exchanger, burners, gas pressure, and safety controls. That combination is what keeps a furnace running 15–20 years instead of 10.
Here’s the full checklist I give Downriver homeowners — what’s on you, what’s on us, and the mistakes I see most often.
Safety First
Before you touch anything: know where your furnace’s power switch is (usually a light-switch-style box on or near the unit) and where the gas shutoff valve is. You don’t need to close the gas valve for basic checks, but you should know how. If you ever smell gas, hear hissing, or feel lightheaded near the furnace, leave the house and call your gas company first — then call us at (734) 559-4688.
Your DIY Furnace Maintenance Checklist
These take minutes, need no special tools, and prevent most of the no-heat calls I run:
- Change the filter every 1–3 months. This is the single most important thing you can do. A clogged filter chokes airflow, overheats the furnace, and shortens its life. Check the size printed on the frame and install with the arrow pointing toward the furnace. Don’t grab the highest MERV rating on the shelf without checking — an overly restrictive filter on marginal ductwork chokes airflow just like a dirty one. Match what your system was designed for.
- Clear space around the furnace. Keep 2–3 feet of clearance. Move boxes, paint cans, and anything flammable away — dust and clutter get pulled into the system.
- Check supply vents and return grilles. Make sure vents are open and not blocked by furniture, rugs, or curtains. Don’t push the couch against the return grille.
- Verify thermostat settings. Confirm it’s on Heat mode with a realistic setpoint. If you have a programmable stat, make sure the schedule still matches your routine.
- Look, listen, and sniff. Banging, screeching, or repeated clicking are red flags. A faint burning-dust smell on first startup is normal; persistent burning or metallic odors are not. Visually check for rust on the cabinet, water pooling around the base, or scorched wire insulation — and if your furnace has a sight glass, the flame should burn steady and blue.
- Test CO detectors monthly. Place them on every level and outside bedrooms. If you ever smell gas or feel lightheaded near the furnace, leave and call your gas company — then call us.
What Our $109 Tune-Up Covers
DIY handles the basics. But there’s a long list of things that need a trained tech with the right instruments — combustion analyzer, manometer, electrical meters. Here’s what we check on every tune-up:
- Heat exchanger inspection. Visual check for cracks, rust, or hot spots — a cracked exchanger leaks carbon monoxide into your home.
- Burner cleaning and flame check. Dirty burners cause uneven flames and nuisance shutoffs. We clean them and verify a steady blue flame.
- Flame sensor and ignitor test. A dirty flame sensor is one of the most common causes of a furnace that starts then shuts off.
- Gas pressure and leak check. Measured against manufacturer specs — wrong pressure means incomplete combustion and wasted gas.
- Safety controls tested. Limit switches, rollout switches, pressure switches — the fail-safes that shut the furnace down if something goes wrong.
- Flue and venting inspection. Confirming vent pipes are connected, sloped right, and free of rust or blockages.
- Temperature rise and airflow. Measured across the furnace and compared to the nameplate range — tells us if the system is overheating from poor airflow.
- Electrical connections. Tightened and inspected — loose connections are a fire risk.
- Blower compartment and ductwork check. Cleaning the blower wheel and compartment, and a visual check of accessible ductwork for disconnected runs or major leaks — leaky ducts can waste 20–30% of your heated air into the attic or crawlspace.
- Condensate drain check. High-efficiency furnaces produce water as they run — a clogged drain line backs up and shuts the system down, or leaks onto the floor. We flush it and verify it flows freely.
- CO test. We check carbon monoxide levels with a combustion analyzer on every visit. Zero ppm is the only acceptable number.
If we find a developing issue during the tune-up — a worn ignitor, a weakening blower motor, early heat exchanger corrosion — we’ll tell you straight and give you real numbers, including honest advice on whether to repair or replace. If you’re already seeing 7 warning signs your furnace needs repair, don’t wait for the annual visit.
When to Schedule It
Early fall — September or October. That’s the sweet spot. You’re ahead of the rush, and if we find something that needs fixing, there’s time to handle it before the first cold snap. Waiting until January means emergency rates and no-heat urgency.
During heating season, keep up the quick monthly checks: filter, vents, and a listen for anything unusual. If your energy bill spikes unexpectedly, that’s worth a service call — not just a filter change.
Your Seasonal Furnace Maintenance Schedule
Fall (September–October): Book your tune-up. Replace the filter, clear the area around the furnace, test CO detectors, and check that vents and returns are unblocked before heating season starts. Turn the heat on once before you actually need it — let it run, listen for anything unusual, and confirm warm air reaches every room.
Winter (December–February): Check the filter monthly — the furnace runs hardest now. Listen for new noises, keep vents clear, and watch for uneven heating between rooms, which can signal ductwork or airflow problems.
Spring (March–April): Swap the filter one last time after heavy use. If you noticed any issues during winter — strange smells, short cycling, rooms that never warmed up — note them now so they’re fixed before next fall.
Summer: If your furnace shares ductwork with central AC, keep the filter changed and the blower compartment clean. It’s also the easiest time to schedule repairs — no rush, no emergency rates.
Don’t Forget the Humidifier
Downriver winters get dry, and a lot of our tune-up customers run a whole-home humidifier like the Aprilaire 500. If you have one, it needs its own yearly attention: replace the water panel (evaporator pad) at the start of heating season, check the water line and drain for clogs, and make sure the humidistat is set right — usually 35–45% in winter. A neglected humidifier grows mold and stops working; a maintained one protects your wood floors, your sinuses, and your furnace from static buildup.
4 Maintenance Mistakes I See Constantly
- Forgetting the filter for months. Set a phone reminder. A dirty filter is the #1 slow killer of furnaces I see.
- Blocking returns with furniture. Then wondering why rooms are cold and the furnace runs constantly.
- Ignoring new noises. Furnaces rarely just die — they whisper first. A new rattle today is a breakdown in February.
- Skipping the pro tune-up entirely. DIY is great but it doesn’t replace combustion testing, gas pressure checks, and heat exchanger inspection. $109 once a year beats a no-heat breakdown in February.
The Bottom Line
Do your half — filter, vents, thermostat, CO detectors. Let us handle the other half once a year. That combination is how furnaces hit 20 years instead of dying at 12.
Not sure if your furnace needs attention now or can wait for fall? Run through our 6 checks to run before you call. If your furnace runs but blows cold air, that’s usually a maintenance-fixable issue — not a death sentence.
Schedule your $109 furnace tune-up — or call (734) 559-4688. If we find something that needs furnace repair, you’ll get an honest diagnosis and real numbers, 24/7 across Trenton, Wyandotte, Woodhaven, Riverview, and all of Downriver.
Key Takeaways
- Change the filter every 1–3 months and keep vents and returns clear — that covers most homeowner maintenance.
- Book a pro tune-up every fall ($109) for combustion testing, gas pressure, electrical safety, and heat exchanger inspection.
- Test CO detectors monthly and know where your furnace’s power switch and gas shutoff valve are.
- New noises, smells, or uneven heating are early warnings — don’t wait for a February breakdown.
Frequently Asked Questions
How often should I service my furnace?
Once a year minimum, ideally in early fall before heating season. If you run the furnace hard from fall through spring, that’s the schedule that keeps warranties valid and catches problems early.
What happens if I don’t service my furnace?
Higher energy bills, more breakdowns, and a shorter lifespan — an unmaintained furnace might last 10 years instead of 15–20. You also risk safety issues like CO leaks from a cracked heat exchanger that nobody inspected.
Can I do furnace maintenance myself?
The basics, yes — filters, vents, thermostat, CO detectors, visual checks. But combustion testing, gas pressure, heat exchanger inspection, and electrical diagnostics need a pro with the right instruments. That’s what the $109 tune-up is for.
How long does a furnace tune-up take?
Usually 60–90 minutes for a thorough job. If a company is in and out in 20 minutes, they didn’t check much.
Does maintenance really extend furnace life?
Yes. The difference between a maintained and unmaintained furnace is roughly 5–10 years of service life. Annual tune-ups also keep most manufacturer warranties valid — skip maintenance and you can void the warranty on a major component failure.
Should I close vents in unused rooms?
No — closing vents raises static pressure and can overheat the heat exchanger. Keep all supply vents open and clear instead.
What does a furnace tune-up cost in Downriver?
Our tune-up is $109. Nationally you’ll see $80–$200 depending on the company and what’s included — the number that matters is what they actually check, not just the price.
Is a maintenance plan worth it?
If you tend to forget the annual visit, yes — it keeps the schedule automatic and catches small problems before they become February breakdowns. Ask us about options when you book.