We’re just over a month into the fall season and with winter quickly approaching I’m sure you know as well as I that means unpredictable weather is coming…

Sunny and mild one day to blistering cold and snow storming the next would not out of the ordinary here in Southern Ontario. Mother Nature sure has a poor sense of humour…

And so, we will all be depending on our furnace to keep our homes at a bearable temperature for the next 6-8 months. But what happens if your furnace decides it’s held out long enough? Well, neither you nor I look forward to that fateful day and what it will mean to our wallets.

What if there was a way to know when your furnace is on its last legs? What if you could plan ahead for the always untimely, but ultimately necessary repair or replacements costs? And taking it one step further, how do you know whether it’s smarter to keep paying for repairs or invest in a new one?

Unfortunately, there is no one size fits all answer to either of the questions. However, I’ve put together a list of things you can look out for that will at least make the decision to repair or replace for your personal circumstances an informed one.

1. The Age of Your System

The average lifespan of a furnace ranges from 15-20 years. This is fairly common knowledge, but still, there’s no way of knowing with absolute certainty when it’ll reach its end.

If you purchased a resale property then it’s unlikely you’ve had to replace the furnace yet. Perhaps the previous owner replaced the home’s original furnace at some point, and while it may not be easy to determine exactly how long it’s been there it is possible.

2. Rising Energy Bills

The HVAC system is one of the biggest energy consumers in homes today.

When a furnace is at the end of its service life, it won’t operate as efficiently as it once did. The amount of energy the furnace uses to keep your home at a comfortable temperature will correlate to the numbers on your monthly energy bill.

A noticeable increase in your monthly energy bills can be a sign that the system is running less efficiently. So, as winter approaches and usage increases, examine your monthly energy bills more closely.

3. Excessive Dust, Dirt, Soot or Rust Particles

If you are noticing dust, dander, soot, rust or dirt build up on or near supply and return air grilles, it could be a sign that something is amiss with your furnace.

Your furnace should be removing the majority of airborne particles via the furnace filter. Check the furnace filter and, if necessary, replace it. This should be done once a quarter. If that doesn’t do the trick it could mean it’s an old furnace on its last legs.

4. Constantly Running

Does the furnace cycle on and off very frequently?

Yes, a furnace will cycle on and off during the course of its normal operation to ensure the home stays at a constant and comfortable temperature.

However, does it seem to just run all the time? If it does, this could be a sign of degradation. 

Monitor your furnace’s on/off pattern, and see if its operation gives you reason to believe that it’s underperforming.

‍5. Rooms are Heating Unevenly

If you are noticing uneven heat distribution between several rooms in your home (or they’re not heated at all) it’s likely due to a problem with your furnace. As your furnace ages, it can struggle to push heat evenly throughout your home.

Cold air coming out of supply air grilles even though the heat is on, and rooms that are warmer than others are two trademarks of a struggling furnace. Both will warrant a closer look at your furnace’s performance.

6. Unusually Noisy

Standing next to your furnace can tell you a lot about its current state.

If you are noticing strange or abnormally loud noises coming from your furnace while in operation it could be the result of cracks, leaks or other structural issues.

Listen closely for some of these noises, and just like a car mechanic you may be able to diagnose a troubled part.

Popping – Parts expanding and contracting from temperature fluctuations in temperature.
Rattling – Loose ducts or equipment.
Screeching – Moving parts such as the blower motor, belts or pulleys are damaged.
Humming – Abnormally loud sound from the blower motor.
Clicking – A clicking noise may indicate your flame sensor or igniter needs to be fixed.
Booming – Often caused by a brief delay during the ignition process. The lingering odor of gas is an immediate red flag.

7. Signs of Wear

Give the furnace a visual inspection.

As with most things a furnace will eventually start showing signs of its age. For example, older furnaces may develop rust or cracks when they’ve been in service for an extended amount of time.

If something doesn’t look right, then it may be a sign of a serious issue going inside the unit.

8. Frequent Repairs

If your furnace requires repairs more often than regular scheduled maintenance, you could be putting that money towards a new unit instead.

How many times in the last to years have to had to call an HVAC technician to service your furnace?

Take a look at the total cost of your next repair bill. If it’s more than half the cost of putting in a new furnace, it’s may be time to bite the bullet.

Having a furnace running optimally through the bitterly cold winter months ahead is a must.

Depending on the age and severity of issues a problematic furnace could also come with health risks caused by carbon monoxide, excess or insufficient moisture levels, or airborne dust and dander particles.

Whatever the circumstances may be, it’s important to keep yourself, your family and/or your tenants safe.

If you have noticed any of the above signs from your furnace then it’s time to speak with a qualified HVAC technician to discuss your options. They will help you decide what makes the most sense for your situation.