10 Signs Your Furnace Needs Service Before it Breaks Down

...and leaves you wrapped up in six blankets, questioning your life choices.

No one plans for their furnace to quit—but furnaces do try to warn you before they call it quits.

The trick is knowing what to listen for (besides your own teeth chattering).

Here are 10 signs your furnace is trying to say: “Help me before it’s too late.”

It's Making Noises Like a Garage Band in the Basement

Banging, rattling, squealing—if your furnace sounds like it's auditioning for a punk rock album, something's up.

  • What to do:

Banging, rattling, squealing—if your furnace sounds like it's auditioning for a punk rock album, something's up.

Your House Has Hot and Cold Personality Issues

If the living room is toasty but the bedroom feels like a meat locker, it's not just your thermostat being passive-agressive.

  • What to do:

Check that your vents are open and unblocked. Still inconsistent? It could be ductwork leaks or airflow issues—so, it's time for a tune-up!

The Furnace Smells Like Trouble

Musty? Could be mold in the system. Metallic or burnt smells? That's a red flag—especially if it smells like burning plastic or wires

  • What to do:

Shut the furnace off and call right away. Some smells are just burning off... others can mean overheating or electrical issues.

It Starts... Then it Stops... Then it Starts Again...

This is called "short cycling." It's like your furnace is doing wind springs and that's not good.

  • What to do:

Short cycling could mean an overheating unit, a bad flame sensor, or a dirty filter. Check the filter first. If it's clean and the problem still continues, let us run diagnostics before you burn out the system.

Your Energy Bill Suddenly Needs a Side Hustle

If your utility bills are climbing but your habits haven't changed, your furnace might be working

  • What to do:

Compare usage with last year. A sudden jump is a sign of inefficiency—usually from a failing component, dirty burners, or bad airflow. Schedule a performance check to pinpoint the cause.

Your Flame is Yellow, Not Blue

Your furnace's flame should burn a steady blue. Yellow, flickering, or lazy flames can indicate carbon monoxide issues. Not Funny!

  • What to do:

Stop using the system and call immediately. This could be a combustion problem or ventilation issue. It's also a reminder ot check your CO detectors immediately.

You Can Feel Air...But It's Weak Like Decaf Coffee

If your furnaces is technically running but airflow is weak, your not getting the heat you are paying for.

  • What to do:

This can be caused by a worn-out blower, clogged ducts, or filter issues. Start with a filter check, then give us a call to test your blower motor and inspect duct pressure.

You're Constantly Micromanaging the Thermostat

If you feel like you’re babysitting the thermostat—up, down, up again—it’s probably not the thermostat’s fault.

  • What to do:

Don’t just replace the thermostat. The underlying issue could be sensor problems, system inefficiency, or airflow imbalance. A pro can isolate it.

Your Furnace is Old Enough to Vote

Furnaces over 15 years old might still run, but they’re like an old pickup truck—reliable until suddenly… they’re not.

  • What to do:

If it’s been more than a year since your last checkup (or you can’t remember ever having one), schedule a safety inspection. And ask us about efficiency upgrades or membership discounts for tune-ups.

You Haven't Had It Checked Since... Who Knows When

If your idea of furnace maintenance is “Well, it’s still running,” we love the optimism. But just like oil changes keep your car running, tune-ups keep your furnace efficient and safe.

  • What to do:

Join the FAN Club! You get two seasonal clean & checks, priority service, and up to $500 discount on repairs and installations. Prevention beats surprise breakdowns every time.

Priority service

Get Help When You Need it Most

As a F.A.N. Club member, you jump to the front of the line. Whether it’s a plumbing emergency or a heating and cooling issue, we’ll make sure your home gets the attention it needs—fast.

Regular maintenance

Prevent Breakdowns

With bi-annual tune-ups for your HVAC system, we’ll catch small issues before they become big problems. From cleaning and inspections to replacing filters and testing components, we’ve got your home covered year-round.

exclusive discounts

Save Big on Repairs and Upgrades

⚡ Enjoy 10% off all repairs and installations

Club members enjoy 10% off all repairs and installations (up to $500 in savings per job). With waived diagnostic fees and priority scheduling, your membership quickly pays for itself!

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Established 1903

Ehret Inc. is a family-owned full-service plumbing, heating and cooling business established in 1903 and currently on the rise with the 5th generation of Ehret family owners.

111 Premier Drive • Belleville, IL • 62220

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