10 Signs Your Furnace Needs Replacing in 2026

Most furnaces last 15–20 years in Ontario homes. Past that point, you're rolling dice. Here are the signals that tell you it's time to start pricing a replacement before it fails on the coldest weekend of the year.

1. It's older than 15 years

Mid-efficiency furnaces installed before 2010 have an AFUE rating of 80% or less. New high-efficiency models hit 96–98%. The math: an older 80% furnace is leaking nearly $1 of every $5 you spend on gas right out the flue.

2. Your gas bills keep climbing

Climbing gas costs aren't always the supplier — a furnace losing efficiency burns more gas to deliver the same heat. Compare last winter's average daily usage to this winter's. A 15–20% jump with no change in habits = a furnace that's working harder than it should.

3. It short-cycles

If your furnace turns on, runs 2–3 minutes, shuts off, then turns back on a few minutes later, that's short-cycling. Causes range from a bad flame sensor (cheap fix) to a cracked heat exchanger (replace the unit). A licensed tech can diagnose in 20 minutes.

4. Banging, rattling, scraping noises

A normal furnace is quiet. Banging on startup is usually delayed ignition (fuel pooling before lighting — dangerous). Rattling is a loose blower wheel or a shifted heat exchanger. Scraping is the blower bearings dying. None of these get better on their own.

5. Uneven heating room-to-room

If one room is always 4°F colder than the rest, the furnace's blower is losing static pressure or the ductwork is leaking. Combined with an older unit, replacement is usually cheaper than chasing duct leaks.

6. Yellow burner flame

Open the furnace cabinet (with the unit off and cool). Look at the burner flame. It should be sharp and blue. Yellow or flickering = incomplete combustion = carbon monoxide risk. Stop running the unit and call us today.

7. Soot, dust, or rust around the unit

Black soot near the flue or rust on the cabinet means the heat exchanger may be cracked. That's a non-negotiable replacement — cracked heat exchangers leak CO into the air you breathe.

8. The pilot light keeps going out

Older furnaces with standing pilots are by definition past their service life. Modern units use electronic ignition. If you're still relighting a pilot every few weeks, you're driving a 1995 truck.

9. Frequent repair calls

Once you're calling a tech 2–3 times a heating season, you're spending replacement money on bandaids. We'll always tell you honestly when it's time to walk away from a unit instead of patching it.

10. Strange smells

A faint sulphur or rotten-egg smell is gas. Get out and call the gas company. A burning-plastic smell on first startup of the season is normal (dust burning off). Persistent musty or smoky smells after a week of running = call us.

What we do differently

We don't sell rentals. We don't push the most expensive unit. We size the equipment to your home (Manual J calculation, not "rule of thumb per square foot") and we put the price in writing before we touch a wrench. Our owner is a BSc-credentialed, TSSA-licensed technician with 10+ years on tools — the same person who answers the phone is the one who'll be on your job.

If your furnace is showing 3+ of these signs, call (416) 258-2460 and we'll come give you an honest assessment. Same-day across the GTA in most cases.