Winter in Snohomish County is no joke. When temperatures drop and the rain sets in, the last thing you want is a furnace that decides to quit on you. The good news? Most furnace breakdowns are preventable — and a little maintenance goes a long way.

Here are five things every homeowner in our area should do to keep their heating system in top shape.

1. Change Your Air Filter Every 1–3 Months

This is the single most impactful thing you can do for your furnace — and it takes about two minutes.

A clogged filter forces your furnace to work harder to pull air through, which strains the blower motor, reduces efficiency, and can cause the system to overheat and shut down. In Snohomish County, where we run our heat for a good chunk of the year, filters get dirty fast.

What to do: Check your filter monthly. If it looks gray and dusty, swap it out. Use a 1-inch MERV 8 filter for most residential systems — don't go higher than MERV 11 without checking with your HVAC tech, as thicker filters can restrict airflow on older systems.

2. Keep the Area Around Your Furnace Clear

Your furnace needs at least 18–24 inches of clearance on all sides for safe operation and proper airflow. It's easy for storage to creep in over time — boxes, holiday decorations, laundry supplies.

Beyond airflow, this is a safety issue. Furnaces produce heat and, in gas systems, combustion gases. Flammable materials stored nearby are a real hazard.

What to do: Do a quick walkthrough of your mechanical room or utility closet before heating season. Clear out anything that's crept too close.

3. Test Your Thermostat Before You Need It

Don't wait for the first cold snap to find out your thermostat isn't communicating with your furnace. Test it in early fall — turn it to heat mode, set it a few degrees above room temperature, and listen for the furnace to kick on within a minute or two.

If it doesn't respond, the issue could be as simple as dead batteries in the thermostat, a tripped breaker, or a loose wire connection. Catching this in September is a lot less stressful than catching it in January.

What to do: Test your heat mode in September or October. Replace thermostat batteries annually while you're at it.

4. Check Your Vents and Registers

Blocked or closed supply and return vents throw off the pressure balance in your duct system, which forces your furnace to work harder and can cause uneven heating throughout your home.

Walk through each room and make sure all registers are open and unobstructed. Furniture, rugs, and curtains are common culprits. Also check that your return air grilles — usually larger, unlouvered vents — aren't blocked.

What to do: Do a full vent audit once a year. Open any closed registers (closing them doesn't save energy — it actually hurts efficiency) and move furniture away from supply vents.

5. Schedule Annual Professional Maintenance

Even if you do everything above, there's no substitute for a professional tune-up once a year. A certified HVAC technician will:

• Inspect the heat exchanger for cracks (a cracked heat exchanger can leak carbon monoxide — this is a serious safety issue)
• Clean the burners and check ignition
• Test the flue and combustion gases
• Lubricate moving parts
• Check electrical connections and controls
• Measure system efficiency

We recommend scheduling your furnace tune-up in late summer or early fall — before the heating season rush. Appointments are easier to get, and you'll head into winter knowing your system is ready.

When to Call Us

If your furnace is making unusual noises (banging, squealing, rattling), short-cycling (turning on and off frequently), producing uneven heat, or if your energy bills have spiked without explanation — those are signs something needs attention.

We serve all of Snohomish County, and we offer same-day and next-day appointments for most service calls. Our diagnostic fee is just $69, and we'll give you a written quote before any work begins.

Don't wait until your furnace fails on the coldest night of the year. A little maintenance now saves a lot of headaches later.