Is it Time to Repair or Replace Your Furnace? Telltale Signs to Look For

Published on: November 28, 2013

When your faithful and long-lived furnace starts forgetting things, like providing heat for example, you might wonder if its end is near. You need to look for warning signs to know if furnace replacement is in your immediate future.


Unusual furnace noises could spell trouble. Loud thumps and sharp knocks are signs of mechanical problems. A buzzing sound could have an abnormal electrical origin. A steady hum may indicate something’s stuck, and rattling sounds tell you something has come loose. All are indicators too loud to ignore.

Unpleasant Sights

If you see puddles, rust spots or signs of corrosion in and around your furnace, you may want to look into furnace replacement. Especially critical, but usually invisible to you, is the condition of the heat exchanger. A qualified HVAC technician, during annual cleaning, will check this element. Any crack or corrosion is serious, as it poses a health risk and a sharp decrease in efficient heating.

Another unpleasant visual sign guiding your decision on furnace replacement is puffback, or soot and dust settling on interior surfaces. It can indicate a weakened HVAC system but also a problem with venting, which is a health hazard as deadly carbon monoxide (CO) can escape back into your home.


An inefficient furnace can cause your energy bills to rise even if you don’t change thermostat settings. A 20-year-old furnace’s efficiency may have only been 75 percent when new, but now it might be down to 60 percent or less. A new high efficiency furnace can achieve up to 98.5 percent efficiency, saving you money over its life.

Frequent repair visits by your HVAC service team may also indicate impending furnace replacement. While trained technicians will try to coax all the efficiency and life out of your furnace, they will know best when your system is past its prime.

For professional help deciding on furnace replacement in the southeast United States, search to find a contractor in your area.