How Much Longer Will Your 20-Year-Old Furnace Last? 

How Much Longer Will Your 20-Year-Old Furnace Last
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How much longer a 20-year-old furnace will last may be better answered by deciding whether you should keep repairing your aged furnace. A 20-year-old furnace may limp along for a couple of years (probably less), but the moment you receive an expensive repair quote past the age of 18, it is wiser to put that money toward a new furnace.


Planning for a furnace replacement with time for research is better than a last-minute decision forced during a cold winter night when it suddenly stops working. 

Replacing heating, ventilation, and air conditioning (HVAC) components are close to the last thing homeowners want to replace. However, you don’t want to be caught off guard, choosing between a costly repair or a replacement decision made in haste. 

Contact furnace installers and repair specialists, Peter Inch & Associates, providing old-fashioned service in the London or St. Thomas areas.  

Read more in our article, Is it Worth Fixing Older HVAC Equipment?


You’ll experience higher energy efficiencies with a new furnace or air conditioner instead of repairing an inevitably ineffective unit. 

The higher its Annual Fuel Utilization Efficiency (AFUE) number, the more efficient it is. AFUE is determined by measuring the percentage of heat produced (BTu)s per dollar of fuel used. An 18 to 20-year-old furnace will measure more than 20% inefficiency, meaning 80% of the power (gas or electricity) goes to heating your home, while 20% is wasted. A new high-efficiency furnace will read between 90-95 AFUE, meaning 90-95% of the power used goes to heating your home, and only 5 – 10% is wasted.


9 signs that your furnace’s efficiency is lessening and its days are numbered.

  • The age of your furnace is over 18 years old 
  • The number of repairs increase
  • The furnace starts and stops
  • There are water leaks around the furnace
  • You notice certain rooms are cold
  • You need to raise the thermostat’s setting to warm the rooms
  • Your heating costs are rising by a lot at once
  • If your older gas furnace flame is yellow, it is a sign the furnace is producing carbon monoxide (CO) 
  • Inefficient airflow from poorly designed or improperly installed ductwork


1)  The age of your furnace is over 18 years old

Whether parts are rusting or components are not performing, 20 years of service is the extent you should expect from your appliance, whether you have a gas or electric furnace. 



2) The number of repairs increase

This is a sure sign that repairs will continue, and it may be time for you to weigh the amount of money spent against investing that money in a high-efficiency model. 


Peter Inch & Associates will always expertly repair your furnace. We are also here to advise you, with many years of experience, about a furnace that is most suitable for your needs when you feel it’s time for a new furnace. Meet our helpful team here.


3) You notice certain rooms are cold

Experiencing sudden and unevenly heated rooms may be a sign your furnace is unable to maintain the circulation of air as well as it once could. 


4) The furnace starts and stops

It is normal to hear your furnace running for a length of time while it heats the home to reach the set temperature and then stop for an extended period until the start of the next cycle. If your furnace starts and stops in shorter bursts, it might indicate the motor’s fan or heat sensor no longer work.


5) Water leaks around your furnace

Water is a normal byproduct of a gas furnace or air conditioner. If the water is puddling during the furnace’s heating cycle, there may be a clogged line, or it could be more serious.


6) You need to raise the thermostat’s setting to warm the rooms

Ask a trusted HVAC installer and repair company to check your thermostat; however, It may also indicate more significant furnace concerns, especially combined with an aged furnace.


7) Your heating costs are rising by a lot at once

Heating costs can vary yearly through rising utility company rates or winter temperature changes. A spike in heating costs also indicates that a furnace is running more to keep the same temperature, lowering its efficiency.


8) If your older gas furnace flame is yellow, it is a sign the furnace is producing carbon monoxide (CO) 

Carbon monoxide poisoning is often fatal before any indication is noticeable. It is signalled by headaches, nausea, dizziness or flu symptoms but is hard to detect due to its lack of odour, colour or taste. Yellow flames are a sure sign that carbon monoxide is present, caused by gas and air not mixing correctly. Dirty fuel, a dirty burner, a blocked air intake or a dirty heat exchanger are possible reasons, and all should be addressed immediately. (Blue flames indicate proper and efficient combustion, while yellow/orange flames are a sign of inadequate heat.) Rusted furnace flues provide cracks through which CO can escape.

Peter Inch & Associates recommends that every home should install a carbon monoxide detector; it will bring you assurance of safety whether you have an older or brand-new furnace. 


9) Inefficient airflow results from poorly designed or improperly installed ductwork

Heated air is designed to travel through completely sealed and correctly distanced heating ducts. When ducts are damaged or punctured (through other renovations, for example) or whose layout is poorly designed, your furnace is forced to work harder than it should. This can lead to a shortened life. 

Contact Peter Inch & Associates online or by phone at (519) 900 9960 to request an inspection of your older furnace and your ductwork by one of our licensed service technicians.  


An aging furnace develops many issues before its unavoidable demise. You will need to decide your comfort between pushing its function through repairs or ending repair costs and gaining efficiency through replacement.

Always choose a heating and cooling company with licensed associates invested in family-valued service.

Want to know more about your heating, plumbing and air conditioning? Tune into our informative podcast with your questions every Saturday morning between 9-10. 


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