Fall Furnace Maintenance Checklist for Washington Winters

Heating season in Western Washington is long, damp, and demanding. Our winters rarely bring extreme cold, but they ask a furnace or heat pump to run steadily for months — and steady running is what finds weaknesses.

The most valuable thing on this list costs nothing: run your heat before you need it. Nearly every no-heat emergency call we take in November is a problem that existed in September and went unnoticed.

What to do yourself

Test the system early

On a mild day in September or October, switch your thermostat to heat and set it about five degrees above room temperature. Let it run 15 to 20 minutes.

You’re checking that it starts promptly, produces genuinely warm air at the registers, runs without unfamiliar noises, and shuts off normally.

A faint burning-dust smell at first startup is normal — summer dust burning off the heat exchanger — and should clear within half an hour.

If anything seems off, you now have weeks to sort it out instead of hours.

Replace the air filter

The highest-value five-minute task in home maintenance.

A clogged filter restricts airflow, which makes the system work harder, raises energy use, and can cause the furnace to overheat and shut itself down on the high-limit switch — the classic “it’s running but blowing cold air” complaint.

Note the size printed on the old filter’s frame, and note the direction of the airflow arrow when installing the new one. Most homes need this every one to three months. During wildfire smoke season, expect to change filters considerably more often.

Clear registers and return vents

Walk the house. Move furniture, rugs, and curtains off supply registers, and make sure return vents aren’t blocked.

Resist the urge to close vents in unused rooms. It seems efficient but raises system pressure, and in enough quantity causes the same airflow problems as a dirty filter.

Test every alarm

Non-negotiable with any gas appliance. Press the test button on every smoke and carbon monoxide alarm, and replace batteries.

You want working CO alarms on every level of your home, including near sleeping areas. Alarms have a service life — usually 7 to 10 years — so check the manufacture date on the back and replace units that have aged out.

Check the thermostat

Replace batteries if it’s battery-powered. Verify it’s set to HEAT and the fan is on AUTO rather than ON. If you have a programmable or smart thermostat, review the schedule — plenty of people are still running last spring’s program.

Clear the area around the furnace

Give it breathing room. Move stored items away, especially anything flammable — paint, solvents, paper, cardboard. Gas furnaces need combustion air, and a furnace closet packed with storage restricts it.

Outdoor tasks for heat pumps

If you have a heat pump, the outdoor unit works all winter and needs attention:

• Clear at least two feet on all sides
• Cut back plants and remove leaves and debris
• Clear the top — it needs vertical airflow too
• Confirm it’s not sitting where water pools and freezes
• Don’t cover it. Unlike an AC-only condenser, a heat pump runs in winter. Covering it blocks the airflow it depends on.

Some frost on the unit in cold damp weather is normal, and the system runs periodic defrost cycles to clear it. Thick ice encasing the coil is not normal and needs a service call.

Check your exhaust vents

High-efficiency furnaces vent through PVC pipes, often out a sidewall. Make sure the intake and exhaust terminations are clear of leaves, nests, and debris — and remember they need to stay clear once leaves start falling in earnest.

Look at the condensate drain

High-efficiency furnaces produce water. Confirm the drain line isn’t kinked or clogged; a blocked drain can trip the overflow switch and shut the furnace down entirely.

What a professional tune-up covers

Some of this genuinely requires a technician, tools, and training:

• Burner inspection and cleaning for proper, complete combustion
• Heat exchanger inspection for cracks — the safety check that matters most
• Flame sensor cleaning, a common cause of nuisance shutdowns
• Gas pressure and combustion analysis to verify it’s firing correctly
• Electrical connections checked and tightened; loose connections cause failures and are a fire risk
• Blower motor and wheel inspected and cleaned
• Safety controls tested — limit switch, pressure switch, rollout switch
• Amp draw measured against specification to catch components beginning to fail
• Refrigerant charge and coils on heat pumps
• Airflow measured, and static pressure checked for duct restrictions

Two reasons this matters beyond peace of mind: most manufacturer warranties require documented annual maintenance to remain valid, and a technician measuring amp draw can often catch a motor that’s starting to fail before it strands you.

Signs you should call before winter

Don’t wait on any of these:

• The furnace doesn’t start, or takes several tries
• Air from the registers isn’t warm
• Unfamiliar noises — banging, grinding, squealing, or a boom at ignition
• A persistent burning smell after the first 30 minutes
• Short cycling — turning on and off repeatedly
• A yellow, flickering burner flame instead of steady blue
• Soot or discoloration around the furnace
• Any carbon monoxide alarm activation
• Any smell of gas — leave the house first, then call your gas utility

The last two are emergencies. Everything else is much cheaper to fix in October than in January.

A quick word on timing

HVAC companies get busiest the week the weather turns. Scheduling maintenance in September or early October means you get an appointment when you want one, and if something needs fixing, there’s time to do it properly rather than as an emergency.

Book a pre-winter tune-up

We’ll do the full inspection — burners, heat exchanger, safeties, electrical, airflow — and tell you honestly what we find, including when the answer is that everything looks good. If we do find something, you’ll get straight options with no pressure.

Serving Tacoma, Fircrest, and communities across Pierce, Kitsap, and Mason Counties.