The fall furnace checklist

Every January we run a week where the board is nothing but no-heat calls, and every year the majority trace back to something that took less than ten October minutes to prevent. This is that list, ordered by how often skipping it becomes somebody's emergency.

1. Change the filter. Today, not conceptually.

A loaded filter makes the furnace run hot, and a furnace that runs hot cycles off on its limit switch, over and over, until a part gives up. It is the single most common root cause on our winter board. If you remember nothing else: filter, first cold week, every year, and again 90 days later.

2. Run the heat for ten minutes before you need it

The first burn of the season should happen on a mild afternoon with you home, not at 11 pm in the first freeze. A dusty burn smell for the first few minutes is normal. A smell that persists past fifteen, any clicking that never becomes flame, or a start-stop-start cycle is your cue to book a window while they are easy to get.

3. Test the thermostat's opinion against a real thermometer

Set it five degrees above room temperature and confirm heat arrives within a few minutes. If the thermostat says 70 and a $6 thermometer on the same wall says 64, your system is being lied to, and it is a cheap fix now versus a mystery later.

4. Clear three feet around the furnace

The storage that migrates toward the furnace all summer, paint cans, boxes, the artificial tree, chokes its combustion air and is a genuine fire consideration. Three feet of clearance, always.

5. Vacuum the return grilles

Two minutes with the brush attachment. Starved returns make everything downstream work harder, and it is the reason one room goes stale first.

6. Press the test button on every CO detector

You should have one on each sleeping floor. Batteries yearly, units replaced at their stamped expiration, and if you do not own one, buy it before you buy anything else on this list. Any Kelvin visit will check your levels free if you ask.

7. Book the tune-up while the calendar is soft

September and October tune-up windows are easy; the first freeze fills the board for weeks. The inspection catches the weak ignitor and the coated flame sensor at rate-book prices on a calm day, which is the entire economic argument for maintenance in one sentence.