Furnace Replacement

Best HVAC Contractor for Furnace Replacement in Markham

Replacing a furnace is a fifteen to twenty year decision. Here is how to know when it is time, which brands to consider, and why Markham homeowners trust Aire One to size and install it right the first time.

Since 1990Serving Ontario

150Technicians, stocked trucks

120,000Homeowners trust us

• Headquartered in Markham
• Carrier Factory Authorized
• Up to 100% Financing

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Reviewed by Matthew Arbab, Managing Director, Aire One Heating & Cooling

A furnace replacement is not a small buy. Done right, the new unit heats your Markham home for the next fifteen to twenty years. Done wrong, an oversized or badly installed furnace wastes fuel, wears out early and never quite keeps the house comfortable. This guide walks through when replacement beats another repair, which brands are worth considering, how financing works, and why the contractor you choose matters as much as the furnace itself. Aire One Heating & Cooling has been sizing and installing furnaces across Ontario since 1990, from our headquarters right here at 2800 John Street in Markham.

Signs It Is Time to Replace, Not Repair

A good contractor will tell you honestly whether a repair will do or whether you are better off replacing. These are the signals that usually tip the decision toward a new furnace:

• The furnace is 15 or more years old. Most gas furnaces last up to about 20 years. Past 15, efficiency drops and breakdowns get more frequent and more expensive.
• Repair costs are climbing. When a single repair approaches a large share of the price of a new unit, or repairs are becoming a yearly event, replacement is usually the smarter money.
• Utility bills keep rising. An aging furnace burns more fuel for the same heat. A new high-efficiency unit can meaningfully cut that monthly cost.
• Visible rust or cracks on the body. Corrosion or cracking is a sign the furnace is breaking down physically, and a cracked heat exchanger is a safety concern.
• Uneven heating. If some rooms never warm up no matter what the thermostat says, the furnace may no longer be sized or working right for the home.
• Changed cycling patterns. A furnace that turns on and off more often than it used to is straining, and that pattern rarely improves on its own.

If you smell gas or suspect a cracked heat exchanger, shut the furnace off, leave the home, and call from outside. That is not a wait-and-see situation.

Brands, Rebates and Financing

Part of picking the best contractor is being offered the right furnace, not just the one unit they happen to stock. Aire One carries a wide selection of top brands, including Carrier, York and Navien, so the furnace is matched to your home rather than the other way around. A proper quote should also help you take advantage of the savings available on a new system:

• Rebates. Upgrading to an energy-efficient furnace can qualify for factory and utility rebates that lower the up-front cost.
• Financing. Aire One offers up to 100% financing on the systems it installs, so a failed furnace does not have to mean a large lump-sum payment.
• Payment flexibility. Choose a low monthly payment, defer payment, or rent the equipment, whichever fits your household best.
• Warranty. New systems come with a strong manufacturer warranty for years of worry-free heating. Ask your advisor for the specific terms on the model you choose.

Why Your Furnace Replacement in Markham Depends on the Contractor

The same furnace, installed two different ways, gives two very different results. Correct sizing, clean ductwork connections and a proper commissioning are what turn a good unit into a comfortable, efficient home. That is where an experienced contractor earns its place:

The Ratings Homeowners Actually Check

Do not take our word for it. These are the current scores for the Aire One Markham head office on the platforms Markham homeowners already use to judge an HVAC company:

Ratings shown for the Aire One Markham head office, verified July 27, 2026.

What a Furnace Replacement Looks Like

A good replacement starts long before the new furnace arrives. An Aire One comfort advisor visits your home, assesses your heating needs and the existing setup, and sizes the unit to the house. You get a clear quote with the brand options, the rebates you qualify for, and financing laid out before you commit. On installation day, factory trained technicians remove the old furnace, install and connect the new one, and make sure it is running correctly before they leave. No guesswork, no pressure, just a properly installed furnace.

A furnace sized to the home and installed to run efficiently for years.

Because the furnace is sized and commissioned properly, you get the efficiency the manufacturer promises, not a powerful unit that short cycles or an undersized one that never keeps up. That is the difference a careful contractor makes over the fifteen to twenty year life of the system.

More Than Just Furnaces

While you are upgrading, it is worth knowing that Aire One handles the rest of the home comfort system too. From our Markham headquarters we install and service furnaces and central heating, air conditioners and ductless systems, heat pumps, water heaters and tankless units, plus indoor air quality equipment. Replacing a furnace and an aging air conditioner together, for example, is often the more efficient and cost-effective move.

We serve Markham and the surrounding communities, including Richmond Hill, Thornhill, Vaughan, Scarborough, North York and Toronto.

Frequently Asked Questions

About the author

Matthew Arbab

Managing Director, Aire One Heating & Cooling

Aire One has been working on Ontario homes since 1990 and is listed by Carrier as a Factory Authorized Dealer employing NATE certified technicians. I would rather tell you that a five dollar filter is all you need than sell you something you do not.