Top Signs Your Furnace Needs Repair: What Tacoma Homeowners Should Watch For

By GreenFlow Heating & Cooling
Oct 16, 2025
3 min read

Few things are worse than waking up to a cold house in the middle of a Washington winter. The good news? Most furnaces give you warning signs before they quit completely. Catching them early can save you from expensive repairs, freezing mornings, and safety risks. Here are the most common warning signs your furnace may need attention and what to do about them.

1. Trouble Starting or Staying On

A healthy furnace should fire up quickly when your thermostat calls for heat. If it hesitates, shuts down early, or takes multiple tries to start, that’s your first red flag. Ignition problems, worn-out wiring, or faulty safety switches are often the cause especially in older furnaces with pilot lights.

Pro Tip: Double-check your thermostat settings first. If it’s on and set correctly but the furnace still won’t start, it’s time for a technician. At GreenFlow, we’ll test your ignition system, inspect safety switches, and track down the electrical fault before it turns into a full breakdown.

2. Weak or Uneven Airflow

If some rooms in your house are toasty while others feel like an icebox, you’re likely dealing with weak or uneven airflow. This can be caused by a failing blower motor, clogged air filter, or leaky ductwork. When airflow drops, your furnace works harder running longer cycles, burning more energy, and wearing out faster.

Pro Tip: Try changing your furnace filter first. If that doesn’t help, schedule a professional inspection. We’ll measure static pressure, check duct sealing, and make sure your blower motor is running efficiently.

3. Strange Noises During Operation

Your furnace should be heard, not felt. Loud bangs, rattles, or high-pitched squeals are never normal. These sounds can indicate anything from loose parts to failing bearings or blower issues.

Pro Tip: Pay attention to when the noise happens and what it sounds like. Noting that helps your technician narrow down the cause faster. In many cases, catching the issue early prevents expensive component failures later.

Schedule Furnace Repair

4. Unusual Smells or Carbon Monoxide Alerts

Furnace problems can sometimes be more than inconvenient they can be dangerous. A persistent burning smell could point to electrical problems, while a musty odor might mean mold in your ductwork. The biggest concern, though, is carbon monoxide (CO). A cracked heat exchanger can leak CO into your home, which is both odorless and deadly.

Pro Tip: If your CO detector ever goes off, shut off the furnace immediately, leave your home, and call the gas company. For other odors, contact GreenFlow. We’ll inspect your heat exchanger, wiring, and venting to make sure your system and your family are safe.

5. Furnace Short Cycling

When your furnace turns on and off too frequently, that’s called short cycling. It wastes energy, strains your components, and often signals underlying problems like a dirty filter, a bad flame sensor, or even an oversized furnace.

Pro Tip: Replace your air filter to rule out airflow restriction. If the issue continues, it’s time for diagnostics. Our team can test your thermostat, clean the flame sensor, and verify your system’s sizing and performance.

Why Furnace Maintenance Matters

Catching problems early is great but preventing them altogether is even better. That’s where annual maintenance comes in.

Think of a fall furnace tune-up like an oil change for your car: a small step that keeps everything running safely and efficiently when winter hits.

During a GreenFlow Heating & Cooling furnace tune-up, we:

Inspect burners, heat exchangers, and safety controls
Check for gas leaks or carbon monoxide risks
Clean and lubricate moving parts
Test efficiency and airflow
29 point inspection, covering everything fromt eh thermostat and air filters to condenser fins and coils
Give you honest feedback on the condition of your system

A single visit can reduce breakdowns, lower heating costs, and extend the lifespan of your furnace.

When Repair Isn’t Enough

Sometimes, repair just isn’t the best investment. If your furnace is 15–20 years old, needs frequent repairs, or struggles to keep up with demand, replacing it may be the smarter long-term move.

New high-efficiency systems like Mitsubishi heat pumps and American Standard furnaces can cut your heating bills dramatically while keeping your home more comfortable.

Stay Warm, Safe, and Stress-Free This Winter

If your furnace is showing signs of trouble, don’t wait for it to quit on the coldest day of the year. Whether you need a quick fix, a full tune-up, or honest advice on replacement, GreenFlow Heating & Cooling is here to help.

We’re a local, family-owned company serving Tacoma, Puyallup, Graham, Spanaway, and the greater Pierce County area, offering expert furnace repair, maintenance, and installation you can trust.