Seasonal · August 5, 2026 · By Doug Kelley, Master Licensed HVAC Technician

The Fall Furnace Checklist: What to Do Before the First Cold Snap

Every year the first hard cold snap hits the upper Shore and every HVAC phone in three counties rings at once. Most of those no-heat calls trace to problems that existed in October: weak ignitors, dirty flame sensors, tired motors. Fall maintenance exists to find them while the fix is a scheduled appointment instead of a cold night. Here is the full checklist, split into what you can do and what we do.

The homeowner's half, one afternoon

• Replace the filter and stock spares for the season
• Test the thermostat by calling for heat and confirming warm air within a few minutes
• Replace thermostat batteries if it takes them; a dying thermostat mimics a dead furnace
• Clear storage away from the furnace: three feet minimum, nothing combustible against it
• Check that supply registers and returns are open and unblocked by furniture and rugs
• Test CO detectors and replace their batteries; combustion heat and attached garages make these mandatory
• For propane and oil: check the tank level and schedule delivery before the rush
• For heat pumps: clear leaves and debris from around the outdoor unit

The professional half, and why it is measurements

A real fall service call is instrumented. On gas equipment we clean and test the flame sensor, inspect the ignitor, check gas pressure with a manometer, examine the heat exchanger, verify venting, measure temperature rise against the rating plate, and run a combustion analysis. On oil equipment the nozzle, filters, and electrodes get replaced and the burner is tuned to a smoke test and efficiency numbers. On heat pumps we verify charge, test defrost, and confirm backup heat stages correctly instead of running constantly. None of that is visible from a homeowner checklist, and all of it is where winter failures hide.

Why October beats December

The practical reason to schedule early: when a fall visit finds a weakening part, you fix it on an ordinary Tuesday. When the same part fails in a cold snap, you join a regional queue on the day everybody else's weak part failed too. The systems that come through January quietly are almost always the ones somebody looked at in the fall. Schedule yours at (443) 310-0206.