Key takeaways
- The Lennox SLP99V and Carrier Infinity 98 are both ENERGY STAR Most Efficient modulating gas furnaces that qualify for federal and provincial rebates across Canada — the efficiency difference between them is less than one percentage point AFUE and rarely justifies a significant price premium on its own.
- Installed cost in Canada ranges from approximately $5,500 to $10,500 for either model depending on city, contractor, capacity, and installation complexity — always compare fully installed quotes, not equipment list prices.
- Both furnaces require their brand-specific proprietary smart thermostat to operate at full variable-speed efficiency; using a standard thermostat reduces both to two-stage operation and negates most of the premium-tier advantage.
- Your installer's experience and parts access with a specific brand matters more in the long run than small specification differences — ask your technician which brand they service most frequently and which their distributor supports most reliably in your region.
- Annual professional maintenance is not optional on either model — it preserves warranty coverage, prevents condensate freeze-ups common in Canadian winters, and is the single most impactful action for achieving the rated 20-to-25-year service life.
Why This Comparison Matters for Canadian Homeowners
Choosing between Lennox and Carrier is one of the most common decisions Canadian homeowners face when it is time to replace a furnace. Both brands occupy the premium tier of the North American HVAC market, both have decades of engineering history, and both offer variable-speed, modulating gas furnaces that can reach AFUE ratings above 98 percent. But the devil is in the details — and for Canadians dealing with outdoor temperatures that regularly drop to -20°C or colder across provinces like Alberta, Manitoba, Saskatchewan, and Ontario, those details can mean hundreds of dollars in annual heating costs and the difference between a furnace that quietly hums through January and one that cycles on and off all night.
This article focuses on the two flagship models that most installers will quote you when you ask for the best: the Lennox SLP99V and the Carrier Infinity 98. Both are modulating variable-speed gas furnaces designed for the coldest climates. We will walk through efficiency ratings, installed cost in Canadian dollars, noise levels, thermostat ecosystems, warranty terms, rebate eligibility under Natural Resources Canada's Greener Homes Initiative, and the hands-on service realities that only come from years of working on these units in the field. If you want to run the numbers for your specific home, our furnace comparison tool lets you stack models side by side with real Canadian data.
Efficiency Ratings: AFUE Explained and What It Means in a Canadian Winter
AFUE stands for Annual Fuel Utilization Efficiency, and it represents the percentage of fuel that is converted into usable heat versus what escapes through the flue. A furnace with a 98% AFUE rating converts 98 cents of every dollar spent on natural gas into heat for your home. The Lennox SLP99V carries a published AFUE of up to 99% — the highest of any residential gas furnace on the North American market. The Carrier Infinity 98 achieves up to 98.5% AFUE, which is still exceptional and qualifies comfortably for maximum rebate tiers under most provincial programs. In practical terms, the AFUE difference between these two models is less than one percentage point. On a $2,400 annual gas bill — a reasonable figure for a 2,000-square-foot home in Winnipeg — the annual savings from that extra half-percent efficiency amounts to roughly $12. AFUE alone should not be the deciding factor.
What matters more in Canadian winters is how the furnace manages its output at partial load, which is the vast majority of operating hours. Both the SLP99V and the Infinity 98 use fully modulating gas valves — meaning they can ramp their heat output continuously from roughly 40% up to 100% of rated capacity rather than simply switching between two stages. This modulation is critical for comfort in a Canadian home because it means the furnace runs longer at lower output during milder weather, maintaining an even temperature instead of blasting heat and then going quiet. Longer run cycles also improve humidity retention and air filtration, since more air passes through your filter per hour. Natural Resources Canada classifies both models as ENERGY STAR Most Efficient, which is the highest designation available and a prerequisite for the largest federal and provincial rebates. Use our efficiency savings calculator to see how an upgrade from your current furnace to either of these models translates into dollar savings at current natural gas rates in your province.
Installed Cost in Canada: What You Will Actually Pay
Sticker price on a furnace means very little without the installation cost, and in Canada those installed costs vary significantly by province, city, and contractor. As of 2025-2026, a Lennox SLP99V in a mid-size Canadian city — think Calgary, Ottawa, or Hamilton — will typically run between $5,800 and $8,500 installed, inclusive of labour, new venting (usually 2-inch or 3-inch PVC for a high-efficiency unit), a new condensate drain, gas line adjustment, and the smart thermostat that unlocks the full variable-speed controls. In Vancouver and Toronto, where labour rates are higher, installed costs can push toward $9,000 to $10,500 for a larger-capacity unit in a complex installation. The Carrier Infinity 98, paired with the Infinity System Control thermostat, runs in a comparable range — typically $5,500 to $8,200 installed in the same markets. Carrier's slightly lower average installed cost reflects both competitive contractor pricing and slightly lower list prices on the equipment itself.
These numbers assume a straightforward swap-out where existing ductwork is in good condition and the furnace location does not require significant structural work. If your home has asbestos duct wrap, requires a gas line upgrade from 1/2-inch to 3/4-inch pipe, or needs a new electrical circuit for the variable-speed blower motor, add $300 to $1,500 to either quote. The good news is that both furnaces are eligible for Canada's Greener Homes Grant (when funded) and for provincial programs in Ontario (Enbridge Home Efficiency Rebate Plus), Alberta (Home Energy Efficiency Tiered Incentive Program — HEETIP), BC Hydro and FortisBC rebates in British Columbia, and Efficiency Nova Scotia programs in the Maritimes. Rebates for upgrading to an ENERGY STAR Most Efficient furnace can range from $500 to $2,500 depending on the province and the AFUE jump from your existing equipment. Our financing options page details how to layer rebates with low-interest financing so the net out-of-pocket cost comes down significantly.
Noise Levels: Which Is Quieter in Your Living Space?
Both the Lennox SLP99V and the Carrier Infinity 98 are marketed as ultra-quiet furnaces, and both deliver on that promise — but they approach acoustics differently. Lennox publishes a sound rating of 0.4 sones for the SLP99V at low-fire operation. For reference, a quiet library registers around 1 sone, and a refrigerator hum is roughly 1 to 1.5 sones. At 0.4 sones, the SLP99V at low fire is barely audible from an adjacent room, and many homeowners report they can no longer tell when it has kicked on unless they are standing near a supply register. This achievement comes from a combination of the variable-speed ECM blower motor, an insulated cabinet, and the fact that the furnace rarely needs to run at full capacity in a well-sized installation, since it modulates down to match the actual heat load.
The Carrier Infinity 98 is also a genuinely quiet machine, rated at approximately 0.5 to 0.7 sones at low-stage operation depending on the capacity. In a basement utility room with a closed door, both furnaces will be imperceptible from the main living floor. The meaningful difference appears in homes where the furnace is installed in a main-floor closet, a mechanical room adjacent to a bedroom, or an open basement in a bungalow. In those scenarios, the Lennox SLP99V's lower sone rating gives it a measurable edge for bedroom-adjacent installations. Carrier compensates with excellent vibration dampening and a well-engineered cabinet design, so the difference is real but not dramatic. If noise is a primary concern for your installation location, ask your installer about cabinet isolation pads and supply-plenum lining — these field modifications cost $100 to $200 and close the gap between the two models significantly.
Variable-Speed Technology and Smart Thermostat Ecosystems
Both furnaces rely on ECM (electronically commutated motor) technology for the blower, which is a permanent magnet motor that adjusts its speed continuously based on system demand. This technology is why high-efficiency variable-speed furnaces use approximately 75% less electricity for blower operation than older PSC (permanent split capacitor) motors — a meaningful saving given that furnace blowers can run thousands of hours per year in a Canadian home with forced-air heating and cooling. The Lennox SLP99V is designed to work within the Lennox iComfort ecosystem. The iComfort S30 or E30 smart thermostat communicates with the furnace over a proprietary protocol that allows full staging control, humidity management, and remote monitoring through the Lennox mobile app. This tight integration means the thermostat and furnace share diagnostic data — a feature that can help your HVAC technician pinpoint a fault code remotely before rolling a truck.
The Carrier Infinity 98 operates within Carrier's Infinity System, which centres on the Infinity System Control thermostat. This thermostat communicates with the furnace, air conditioner, air handler, and air quality accessories over Carrier's own ABCD bus protocol. The Infinity System has a well-deserved reputation for precise temperature control and zoning capability — Carrier's Greenspeed Intelligence logic continuously adjusts not just the furnace but the entire system simultaneously to optimize efficiency. If you already own Carrier air conditioning or plan to add it, staying within the Infinity ecosystem provides the tightest system-level integration available. If you are mixing brands — say, keeping a Lennox AC on a Carrier furnace — you will lose most of the smart staging benefits and revert to basic two-stage communication. Both furnaces are compatible with Google Home and Amazon Alexa for basic voice control via their respective apps. Explore our full lineup of variable-speed furnaces to compare additional options in this category.
Warranty Coverage: Reading the Fine Print
Warranty terms on premium furnaces can look similar at a glance but diverge significantly in the details. Lennox offers a 20-year limited warranty on the heat exchanger and a 10-year limited parts warranty on the SLP99V — but both require registration within 60 days of installation through the Lennox owner registration portal. If you fail to register, the heat exchanger warranty drops to 10 years and the parts warranty falls to 5 years. This registration requirement catches homeowners off guard more often than it should. Always confirm with your installer that registration is part of their post-installation process, or register yourself using the serial number on the unit. Lennox does not cover labour costs under the standard warranty, so a heat exchanger failure outside the labour warranty window from your installing contractor means you pay for the technician's time even if the part itself is free.
Carrier offers a 20-year limited heat exchanger warranty and a 10-year limited parts warranty on the Infinity 98, with the same registration-within-90-days requirement. Carrier has historically maintained a slightly broader network of authorized warranty service dealers in remote Canadian communities, which matters if you are in a smaller centre in northern Ontario, the BC Interior, or rural Alberta. Both brands have factory-authorized service networks across Canada's major urban centres — you will not struggle to find a qualified technician in Toronto, Calgary, Edmonton, Ottawa, or Vancouver. The practical differentiator is what happens when a part fails at 11 years. At that point, neither warranty covers the component, but brand matters for parts availability. Both Lennox and Carrier maintain strong Canadian parts distribution, with most common components available within 24 to 48 hours through their respective distributor networks. Consider maintenance plans that cover labour costs across the warranty period and beyond.
Reliability and Long-Term Ownership in Cold Climates
Any honest discussion of furnace reliability needs to acknowledge the limits of available data. Unlike the automotive industry, there is no standardized third-party reliability database for residential HVAC equipment in Canada. Manufacturer-reported failure rates are marketing documents. What we do have is the accumulated field experience of technicians who service these units year over year, and the pattern that emerges from that experience is nuanced. The Lennox SLP99V's modulating gas valve has historically been a warranty service item at a higher rate than the two-stage valves found on less sophisticated furnaces. This is not inherently a design flaw; it is partly a consequence of the valve being asked to perform continuous micro-adjustments over tens of thousands of cycles per heating season. Lennox has iterated on this valve design over multiple production years, and current-generation units from 2023 onward have shown improved durability in field reports from technicians across the Canadian market.
The Carrier Infinity 98's control board and Infinity System Control communication protocol are the components most frequently cited by Canadian technicians as the source of intermittent faults — particularly in older installations where the communication wire between the thermostat and furnace was not shielded from electrical interference. Modern installations using the recommended 18/4 shielded thermostat wire largely eliminate this issue. Both furnaces benefit enormously from annual preventive maintenance: cleaning the flame sensor, inspecting the condensate drain and trap, checking the inducer motor bearings, and verifying the pressure switch operation. In Canadian climates where furnaces run from October through April — often six months or more — an annual inspection before the heating season is not optional, it is the difference between a $150 tune-up and a $900 emergency call on a January weekend. Our emergency furnace help resource has triage steps if you suspect a fault mid-season.
Which Furnace Should You Choose? A Province-by-Province Perspective
If you are in Alberta or Saskatchewan, where natural gas is the dominant fuel, winters are severe, and heating seasons run long, both furnaces are excellent choices and the decision often comes down to which brand your chosen installer services most frequently. A technician who works on Carrier equipment daily will have better diagnostic instincts on an Infinity 98 than one who primarily services Lennox, and vice versa. Ask your installer directly: which brand do you stock parts for, which do you see fewer callbacks on, and which brand does your distributor support most strongly in this market? That answer is worth more than any spec sheet comparison. In Calgary and Edmonton, both brands have strong installer networks — use our furnace installers in Calgary and furnace installers in Edmonton pages to find certified technicians for each brand.
In Ontario — particularly in the Greater Toronto Area and Ottawa — Enbridge's Home Efficiency Rebate Plus program has driven strong adoption of both brands at the ENERGY STAR Most Efficient tier. The Lennox SLP99V tends to command a slight premium in the Toronto market because Lennox has historically invested more heavily in dealer training and co-op marketing in Ontario. The Carrier Infinity 98 is equally capable and often available at a lower installed cost through competitive Carrier dealers. In British Columbia, the FortisBC and BC Hydro rebate programs apply to natural gas furnace replacements, and both brands qualify. In Quebec, Energir runs efficiency rebate programs that cover high-AFUE gas furnaces, though the provincial government's broader push toward electrification means heat pumps are increasingly incentivized over gas equipment. Use our furnace size calculator to confirm the right capacity before committing to either brand, and explore our pages for Lennox furnaces and Carrier furnaces for full model lineups and current Canadian pricing.
Frequently asked questions
Is the Lennox SLP99V worth the extra cost over the Carrier Infinity 98 in Canada?+
For most Canadian homeowners, the answer depends on your specific situation rather than a blanket yes or no. The Lennox SLP99V's fractional AFUE advantage — roughly half a percentage point — translates to a small annual fuel saving that rarely justifies a significant price premium on its own. Where the SLP99V earns its cost is in extremely cold climates like northern Alberta or Saskatchewan, in larger homes above 2,500 square feet where cumulative efficiency gains compound meaningfully, and in installations where the furnace is adjacent to living or sleeping spaces where the industry-leading noise rating matters. If your installer quotes both models within $500 of each other installed, the SLP99V's slightly higher ceiling efficiency and lower noise floor make it the stronger choice. If the gap is $1,000 or more, the Infinity 98 is the better value proposition for the majority of Canadian homes.
Do both the Lennox SLP99V and Carrier Infinity 98 qualify for Canadian government rebates?+
Yes. Both models carry ENERGY STAR Most Efficient certification, which is the highest efficiency designation from Natural Resources Canada and the primary qualification threshold for federal and most provincial rebate programs. Under Canada's Greener Homes Initiative (when funded), ENERGY STAR Most Efficient gas furnaces have qualified for grants of up to $1,500. Provincial programs add to this: Ontario's Enbridge Home Efficiency Rebate Plus, Alberta's HEETIP, FortisBC and BC Hydro rebates in British Columbia, and Efficiency Nova Scotia all recognize both models. Rebate amounts vary by province, program year, and the AFUE improvement over your replaced equipment — homes upgrading from an older 80% AFUE furnace typically qualify for the largest tiers. Always confirm current rebate availability with your provincial program administrator before purchase, as funding periods and amounts change annually.
What maintenance does each furnace require, and how does it affect long-term cost?+
Both the Lennox SLP99V and Carrier Infinity 98 require annual professional maintenance to preserve warranty coverage and operate at rated efficiency. A standard annual tune-up covers cleaning the secondary heat exchanger, inspecting and cleaning the condensate trap and drain line (critical in Canadian winters where freeze-ups cause pressure switch lockouts), testing and cleaning the flame sensor, checking inducer motor current draw, verifying gas pressure at the manifold, and inspecting the modulating gas valve operation. Expect to pay $120 to $200 for a thorough tune-up from a qualified technician. Both furnaces have diagnostic self-reporting via their respective thermostat displays, which simplifies fault diagnosis and can reduce the labour cost of a service call. Annual maintenance pays for itself many times over by preventing the kind of deferred failures that turn a $50 part into a $600 emergency call.
Can I use a regular thermostat with the Lennox SLP99V or Carrier Infinity 98?+
Technically yes — both furnaces can be operated with a standard two-stage thermostat using conventional 24-volt wiring. However, doing so disables the full variable-speed modulation and reduces both furnaces to two-stage operation, which dramatically reduces their efficiency advantage, comfort benefit, and noise reduction. You would essentially be paying a premium price for a furnace running in a degraded mode. Lennox requires the iComfort S30 or E30, and Carrier requires an Infinity System Control thermostat, to unlock continuous modulation, humidity management, and the diagnostic communication features. These proprietary thermostats add $300 to $600 to the installed cost but are effectively mandatory if you want the furnace to perform as rated. Budget for the thermostat as part of the total system cost, not as an optional upgrade.
How long do these furnaces typically last in Canadian climate conditions?+
Premium variable-speed modulating furnaces like the SLP99V and Infinity 98 are engineered for a service life of 20 to 25 years with proper maintenance, compared to 15 to 18 years for entry-level equipment. Canadian climate conditions are demanding — a furnace in Winnipeg or Regina may accumulate 2,500 or more operating hours per heating season, compared to 1,200 to 1,500 hours in milder climates. The heat exchanger carries the longest warranty on both models and is typically the most durable component. Control boards, gas valves, and inducer motors are the most likely service items in years 10 through 15. Keeping annual maintenance current, replacing the air filter every 60 to 90 days, and addressing minor fault codes promptly are the highest-impact actions a homeowner can take to push either furnace toward the upper end of its lifespan.
Which brand has better parts availability across smaller Canadian cities and rural areas?+
Both Lennox and Carrier maintain national distribution networks in Canada through independent HVAC distributors. In major urban centres — Toronto, Calgary, Edmonton, Vancouver, Ottawa, Montreal — same-day or next-day parts availability is standard for both brands. In smaller cities like Lethbridge, Prince George, Sudbury, or Fredericton, availability depends on your regional distributor's stock depth. Carrier has historically maintained a slightly broader rural dealer network in western Canada, while Lennox has strong penetration in Ontario's mid-size markets. For genuinely remote locations — northern BC, rural Manitoba, or Labrador — neither brand guarantees fast parts delivery, and the critical factor becomes whether your local HVAC contractor stocks common wear items like flame sensors, pressure switches, and control boards for the brand they service most frequently. Ask your installer this directly before deciding.
Furnace.sale Editorial Team
Heating & Home Comfort Editors
The Furnace.sale editorial team researches furnace pricing, efficiency, rebates and financing across every Canadian province to keep our buying guides accurate and up to date.
Updated 2026-04-14