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8 Signs That Your Furnace Needs To Be Repaired or Replaced

Warning Signs for Furnace

Information is the key to staying prepared

Please don’t wait until it’s too late to find out something’s wrong with your furnace and HVAC system. Allowing a problem to go undiagnosed is an easy way to rack up costly repair fees. Instead, review the most common warning signs that your heating system might need some attention. 

By arming yourself with the information below and keeping an eye out for the following warning signs, you can maintain a well-functioning furnace, as well as an energy-efficient and comfortable home.

1. The Age of Your Furnace

A practical warning sign regarding the health and longevity of your furnace is its age. But what’s old, anyway? The average life expectancy of a furnace is about 15 years. That means that once your heater reaches 15 or older, it’s much more likely to break down.

If your furnace falls into the 15+ year category, it’s safe to assume you’ll need to replace it sooner rather than later. Instead of waiting to purchase a heater after your current unit malfunctions, allow yourself the time and flexibility to shop for a replacement during a less stressful time. Doing so can help save you money, as you’ll be more able to take advantage of sales and any available rebates.

2. You’ve Had More Than One Furnace Repair in the Last 2 Years

Age alone isn’t the only indicator that you could need a new furnace. If you’ve had to invest in multiple repairs within the last 2 years, it could be a sign that your home needs a new system.

Over time, these repairs can start to add up, costing you more money and frustration than your heater is worth. If you struggle to maintain your system and waiting for replacement parts, you might be better off investing in a new heating system.

A replacement system will function more efficiently overall, have a brand new warranty, and be easier to repair if and when something does require maintenance.

3. Uneven Temperatures in Your Home

No matter what kind of system you have–furnace, heat pump, or something else–if there’s cold spots in your home, it’s a problem. 

If you’ve ever felt comfortable while leaving one room only to find the next room too stuffy or too cold, your unit might be having trouble getting heated air through your ductwork.

In these instances, your first instinct will be to adjust your thermostat., this will only overheat comfortable rooms in your home. The result? Higher energy bills and an overworked furnace.

4. Unexplained Spikes in Your Energy Bill

Speaking of higher energy bills, a sudden spike in your monthly gas and electric bill without any dramatic weather changes could be a sign of trouble for your furnace. That’s because heaters lose their efficiency the older they get. When efficiency rates decrease, your furnace will spend more time running as it tries to heat your home, causing higher energy bills.


If you notice your heating system is running longer than it used to, that’s a definite warning sign. It’s a clear sign that your unit is on the decline and may need replacement. You can reduce your energy bill with a new unit, like a heat pump or ductless system. Many of our customers see their energy bills plummet within the first month or two!

5. Feeling Ill in Your Home

This warning sign is crucial in maintaining your safety, as well as in diagnosing problems with your furnace. If you ever notice frequent headaches, burning eyes, nausea, or flu-like symptoms, it could be a sign of dangerous carbon monoxide in your home. Your furnace could also be the culprit.

As your furnace ages, cracks can occur in the heat exchanger. Those cracks can allow carbon monoxide to leak out, which is dangerous to you and your family.

So if you experience any of these health symptoms, take action! Open windows to air out your home. Then, contact a gas service technician. 

And a little PSA: every homeowner should have a carbon monoxide detector in their home. Since carbon monoxide is not visible, it can be difficult to identify its presence.

6. Changes in the Color of the Burner Flame

Another indicator of carbon monoxide production is the color of your furnace’s burner flame. A healthy heater will have a blue burner flame, showing that enough gas is powering the furnace. However, if the burner flame is yellow, this could be a sign that the unit is leaking carbon monoxide.

Although you may not be in the habit of checking the color of your heater’s burner flame, it’s an easy habit to create that could end up saving lives.

7. Air Contamination

While less severe than carbon monoxide poisoning, another environmental indicator that your furnace needs repair is dry air in your home. Air contamination can be particularly troublesome if you or your family suffer from airborne allergies.

An older furnace can lose its ability to promote airflow, causing dust, mold, pollen, and dander to accumulate in ducts and spread throughout the home. 

8. Uncharacteristic Sounds When Your Furnace is Running

Perhaps the most obvious warning sign that your heating system needs attention is odd-sounding noises. If you hear any strange noises, such as bangs, pops, rattles, or whistles coming from your attic, there’s a good chance that it isn’t running correctly.

A professional can help you diagnose any odd noises, as well as any of the above issues your furnace might be experiencing. A trusted Austin HVAC technician is a tremendous resource to maximize your finances when you have a faulty or older furnace. Our technicians will let you know when all that’s needed is a simple repair, or if a furnace is genuinely in need of replacement.

Call McCullough today at (512) 866-9821 to have your heating system inspected. If needed, there’s no better dealer in Austin to recommend and install a new furnace for your home.

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