7 Warning Signs Your Furnace Is In Trouble This Winter

Brandon Quigley

Expert Contributor | Quigley Heating & Air Conditioning Quigley Heating & Air Conditioning

The Good Life Park Cities Jan 2026

Winter in Dallas is unpredictable. When your furnace finally gives up, it usually picks the worst possible night—Christmas Eve, Super Bowl Sunday, or the middle of a polar vortex. The good news? Your furnace almost always shows warning signs before it dies completely. Catch these early and avoid the inconvenience of an untimely breakdown.

1. Age 15+ Years (The #1 Predictor of Failure)

Most furnaces are designed to last 15–20 years with perfect maintenance. If yours was installed before 2010, you’re on borrowed time. The older it gets, the more likely critical parts (heat exchanger, blower motor, inducer) are cracked or seized.

2. Strange Noises That Are Getting Louder

Rattling or buzzing = loose panels or a failing blower motor
Screeching or grinding = bad bearings about to seize
Booming or banging on startup = delayed ignition (dangerous and a common heat-exchanger-crack symptom)

3. Yellow or Flickering Flame (Instead of Steady Blue)

Open the front panel (with the power off!) and look at the burner flames. They should be steady blue. A yellow, orange, or flickering flame usually means cracked heat exchanger, incomplete combustion, or soot buildup—all expensive and potentially deadly problems.

4. Skyrocketing Heating Bills With No Explanation

If your gas or electric bill jumped 30–50% compared to last year but you’re using the same thermostat settings, your furnace is working overtime because it’s losing efficiency fast. A failing heat exchanger or clogged blower can cause exactly this.

5. Constant Cycling (Short Cycling)

Your furnace turns on and off every few minutes instead of running a normal 8–12 minute cycle. This is usually caused by:

Overheating due to restricted airflow (dirty filter or failing limit switch)
Bad thermostat
Undersized ductwork finally giving up

Short cycling destroys components and is the fastest way to kill a furnace.

6. Excessive Dust, Soot, or Rust Around the Furnace

Black soot near the burners = cracked heat exchanger leaking combustion gases
Rust on the furnace cabinet or flue pipe = condensation problems eating metal

7. Your Family Is Experiencing Headaches, Nausea, or Burning Eyes

This is the scariest one. Carbon monoxide leaks often happen gradually as heat exchangers develop tiny cracks. Symptoms mimic the flu. If multiple family members feel sick only when the heat is running—and feel better when they leave the house—shut the furnace off immediately and call us immediately.

What Should You Do Right Now?

1. Check your furnace age (sticker on the unit).

2. Change the filter if it’s been more than 3 months.

3. Schedule a precision tune-up and safety inspection before January 23rd. (We’re offering FREE carbon monoxide testing and a 21-point safety check with every tune-up booked this month—normally $149.)

Be sure to stay warm and safe this winter by calling the Quigley Heating & Air Team to reserve your tune up and free carbon monoxide test by calling 214-390-4829. Or visit their website www.quigleyac.com.