Is the upgrade worth it? What AFUE, energy savings, and rebates mean for your home this winter.
The short answer: A high-efficiency furnace turns up to 98.5% of the fuel it burns into heat, compared with 60–80% for older units. For most Markham homes with an aging furnace, that efficiency lowers heating bills enough to make the upgrade worth it — especially when rebates and financing help cover the upfront cost.
If your furnace is more than 15 years old, a big part of the gas you pay for is going up the chimney instead of warming your home. A modern high-efficiency furnace changes that math — and in Markham's long heating season, the savings add up quickly.
This guide explains what makes a furnace high-efficiency, how much you can save, and how to tell whether the upgrade is worth it for your home. If you'd rather get a straight answer for your specific furnace, you can book a free home assessment any time.
Key takeaways
- "High-efficiency" means an AFUE of 90% or higher — top models reach up to 98.5%.
- Older furnaces often run at just 60–80% AFUE, wasting a large share of your gas.
- The upgrade usually pays for itself over time through lower monthly bills.
- Rebates and financing can offset much of the upfront cost.
- If repairs are getting expensive on an old unit, replacing beats repairing.
What Makes a Furnace "High-Efficiency"?
Furnace efficiency is measured by AFUE (Annual Fuel Utilization Efficiency) — the percentage of fuel that becomes usable heat. A 95% AFUE furnace turns 95 cents of every fuel dollar into warmth, with only 5% lost. Anything rated 90% AFUE or higher is considered high-efficiency, and the best condensing models reach up to 98.5%.
By contrast, many older furnaces still running in Markham homes operate at 60–80% AFUE. That gap is exactly where your savings come from when you upgrade.
The Benefits of a High-Efficiency Furnace
Beyond the AFUE number, here's what a modern unit delivers day to day:
- Lower heating bills. Less wasted fuel means a smaller gas bill every month of the heating season.
- More even comfort. Variable-speed models hold a steadier temperature with fewer cold spots.
- Quieter operation. Newer furnaces run softer than the loud on/off cycling of older units.
- Cleaner and greener. Burning less fuel for the same heat means a smaller carbon footprint.
- Rebate eligibility. High-efficiency equipment often qualifies for energy-efficiency incentives.
- Reliability. A new system under warranty means fewer breakdowns on the coldest nights.
High-Efficiency vs. Standard Furnace
Here's how a modern high-efficiency furnace compares with an older, standard-efficiency unit:
| Factor | High-efficiency | Older / standard |
|---|---|---|
| AFUE | 90–98.5% | 60–80% |
| Heating bills | Lower | Higher |
| Comfort | Even, steady heat | More temperature swings |
| Noise | Quiet | Louder cycling |
| Rebates | Often eligible | Rarely |
Is the Upgrade Worth It for Your Home?
The upgrade makes the most sense when one or more of these is true:
- Your furnace is 15 or more years old and running at a low AFUE.
- Repairs are adding up — a good rule of thumb is that if a repair costs more than half the price of a new unit, replacing is the smarter move.
- Your heating bills keep climbing even though your usage hasn't changed.
- Rooms feel uneven, or the furnace is short-cycling and noisy.
If you're weighing a repair against a replacement, our team can lay out both paths honestly. Explore our HVAC servicing and repairs, and keep any new system performing with a maintenance and protection plan.
What It Costs and How to Save
The upfront price depends on your home's size, the model you choose, and the complexity of the installation. Two things make it easier to manage: rebates on qualifying high-efficiency equipment, and financing that spreads the cost into predictable monthly payments. Because the new furnace also lowers your energy use, part of the investment pays you back over time. Our heating and cooling services include a free assessment so you get an exact recommendation and quote for your home — no guesswork.
Not sure if it's time to upgrade?
Trusted in Markham since 1990. Book a free assessment and we'll tell you honestly whether to repair or replace.
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Frequently Asked Questions
What AFUE should a high-efficiency furnace have?
A furnace is considered high-efficiency at 90% AFUE or higher. Entry high-efficiency models start around 90 to 95%, while top condensing units reach up to 98.5%. The higher the AFUE, the less fuel is wasted.
Is a high-efficiency furnace worth it in Markham?
For most homes with an older, low-AFUE furnace, yes. Markham's long heating season means the monthly savings add up, and rebates plus financing help offset the upfront cost so the upgrade pays back over time.
How much can a high-efficiency furnace save?
Savings depend on your old furnace's AFUE and how much you heat. Moving from a 70% unit to a 96% unit means far less wasted fuel, which shows up as a lower gas bill every month of the winter. A home assessment gives you a realistic estimate.
Are there rebates for a high-efficiency furnace?
Often, yes. Energy-efficiency programs frequently include incentives for qualifying high-efficiency equipment, but they change over time. Check current federal and provincial programs and ask our team which ones apply to your project.
How long does a high-efficiency furnace last?
With annual maintenance, a quality furnace typically lasts about 15 to 20 years. Keeping up with yearly service protects its efficiency and helps it reach the top of that range.
Sources & Helpful Resources
Matthew leads the Aire One Markham / Metro Toronto team, helping homeowners choose the right furnace, heat pump, and comfort solutions. Aire One has been a trusted, Carrier Factory Authorized Dealer since 1990.