How to Tell the Age of My Furnace?

Couple on computer researching How To Tell The Age Of My Furnace?

So you may know how long the average furnace lasts, but you’re not sure how old your furnace actually is.

It’s important to know how old your furnace is. Having a clear picture of the unit’s age can help you properly plan and budget for potential furnace repairs or replacements. This is especially essential in the frigid GTA, where we never want to be stuck without heat! 

Unfortunately, for many, it’s tricky to figure out the exact age of a furnace. When you move into a new residence, the former occupants don’t always provide detailed information, leaving you to investigate the new space and test out your new appliances. Then, when it comes time to turn on your furnace, you cross your fingers and hope for the best.

Here are some quick and easy tips that will help you answer the question, “How old is my furnace?”

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How Old is My Furnace?

If you don’t know the age of your furnace, you can usually find the information on the furnace itself. In recent years, improved labelling has made it easier to find the age of newer furnace models, but older furnaces might require some extra detective work.

When Was It Installed or Last Serviced?

If the manufacturing date isn’t obvious, there are other ways to determine the age of your furnace. First, look for documentation, like a manual. If you’re lucky, it’ll have a date that gives you an idea of how old your furnace is. If you don’t have a manual, look for a service tag. HVAC technicians commonly leave information about service appointments. It might not include the manufacture date but could indicate when the appliance was installed.

Is There a Label?

If you cannot find a helpful manual or service tag, the next step is to search for a label. Before you do anything, though, turn off the furnace. You can do this by shutting off the power switch. Better yet, find the master fuse and turn off the circuit breaker. Once the unit is safely off, attempt to find a label. Depending on the particular system, it may be located on the exterior or interior panelling. 

If you don’t see a sticker or tag attached to the outside of your furnace, there’s a good chance one will be located inside. You can access the interior panelling by opening the removable door. The label may or may not list the date, but it is likely to have a serial number which is exactly what you need to determine the manufacture date.

If your furnace has a red tag – read our guide on what to do with a red tag furnace.

Is There a Stamp or Imprint Inside?

Most newer furnaces will have the label you are looking for, but serial numbers on older furnaces might be hiding on one of the components inside the appliance. Again, ensuring the unit is turned off, search for an imprinted number of parts such as the gas valve, electric relay, blower compartment, fan blades, or access panels.

How to Research the Serial Number

If you’ve identified the serial number, you can usually use it to determine the age of your furnace. How? A quick way is to perform an online search. Enter “find manufacturing date” and your furnace brand or manufacturer. This search will bring you to a website with serial number information.

You’ll find that a furnace’s serial number is essentially a code. Typically, the first four numbers represent the week and year it was built. However, if the serial number starts with a mix of numbers and letters, that may signify the month and year of production. (Either A or M can represent January, meaning B or N would indicate February, and so on.)

Here are some examples of how to interpret the serial numbers for some leading furnace brands:

Trane Furnace

71422L41G (7 represents the year and 14 is the week = April 2007)

12331234B (12 represents the year and 33 is the week = August 2012)

Bryant Furnace

M3P45678 (M represents the 1st month and 3 is the year = January 1983)

920545678 (92 represents the year and 05 is the month = May 1992)

Goodman Furnace

96-45678 (96 represents the year = 1996)

0607456789 (06 represents the year and 07 is the month = June 2007)

If your online search doesn’t lead anywhere, try contacting the manufacturer directly. Come prepared since customer service might ask for a picture of your heating system to help them determine the furnace’s age.

How Long Do Furnaces Last?

When furnace age is no longer a question, you can determine how much longer your heating system will reliably warm your Ontario home. On average, you have about 15 years before you should start to consider furnace replacement (or you risk facing costly repairs). A furnace can last longer than this, especially if experienced technicians perform regular HVAC maintenance.

Besides age and repair bills, there are other signs it is time for a new furnace. These include a furnace that makes loud noises, a cold home (even when you make significant adjustments to the thermostat) and increased energy costs. Replacing an older furnace with a new furnace will not only help you feel warm again, but it can also help to reduce utility bills because many new models have significantly higher energy efficiency ratings.

Talk to Dr HVAC for Professional Furnace Advice

If you are still having trouble identifying the age of your furnace, or have realized it is time for a replacement system, don’t hesitate to speak with some of the most experienced technicians in the industry. We will inspect Trane, Goodman and Bryant brand furnaces. If cost is a concern, we offer HVAC system financing options to make replacing your furnace manageable for your budget.

With our furnace and HVAC inspection checklist, Dr HVAC will inspect the overall operations of your existing furnace and determine its life expectancy. Should you require new furnace installation, you can count on us for quality work backed by a 100% satisfaction guarantee. We’ll make your home cozy in no time!



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