Lennox Furnace Review

Lennox is one of the oldest and most recognized names in North American HVAC, founded in 1895 and operating as a publicly traded, standalone manufacturer — not part of a larger multi-brand conglomerate.

That independence shapes the brand's positioning: Lennox sits at the premium end of the residential furnace market, competing on efficiency ceiling, comfort refinement, and its proprietary iComfort control ecosystem rather than on price.

This review covers the current Lennox gas and oil furnace lineup — 25 models spanning the flagship 99% AFUE SLP99V down to entry-level 80% AFUE single-stage units — with installed pricing, warranty analysis, and feedback from the 264 homeowners who've reviewed their Lennox furnace on our platform.

The Bottom Line

Lennox is a genuinely premium brand that sets the efficiency ceiling in the residential furnace category with the 99% AFUE SLP99V, and extends that technical edge through a strong modulating and two-stage lineup. Owner sentiment on our platform is among the most positive we track — roughly nine in ten ratings are positive across 264 reviews.

The trade-off is cost: installed pricing runs noticeably above Carrier, Trane, and most ICP-family alternatives, and the proprietary iComfort control system can drive long-term service cost higher than a conventional thermostat setup.

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Lennox is a good fit if you:

• Want the highest AFUE efficiency available and are willing to pay for it
• Value the iComfort communicating ecosystem and plan to stay in the home long enough to realize comfort-tuning benefits
• Prefer a standalone, widely recognized brand over the multi-badge ICP or Daikin families
• Live in a region with a strong Lennox dealer network

Consider other brands if you:

• Are price-sensitive — equivalent 96%+ two-stage performance is available for meaningfully less from Carrier, Bryant, KeepRite, or Goodman
• Want a unit replacement guarantee in your warranty — no Lennox model currently offers one

What Lennox Owners Are Saying

Across 264 owner reviews submitted to our platform, Lennox furnaces carry an average rating of about 4.6 out of 5, with sentiment skewing strongly positive — roughly nine in ten ratings fall in the 4–5 star range. The average reported installed price is around $6,600, placing Lennox at the premium end of the installed-cost spectrum.

The most frequently cited positives, in order: strong day-to-day performance, quiet operation, energy efficiency, and reliability. The quiet-operation volume is particularly notable — it shows up in 186 of 264 reviews, more than any other single attribute.

"Great features" is also called out more often than on most competitor brands, reflecting the iComfort control system and Lennox's SilentComfort cabinet design.

One Lennox owner shared:

It's so quiet I don't even hear it kicking on. My old furnace would shake my bedroom floor.

Another homeowner who switched to a mid-tier Lennox described consistent temperatures throughout the house and exceptional contractor experience as the defining change from their previous furnace.

Balanced against the positive sentiment, a minority of owners flagged concrete issues: noise complaints (roughly five mentions) typically involving the blower's shut-down behaviour or specific installations where the new Lennox ran louder than the unit it replaced, a small number of reliability concerns including one report of a heat exchanger crack on an older unit, and recurring comments about cost — described as expensive even by owners who otherwise rated their furnace five stars.

A few owners also noted friction with Lennox's registration requirements to activate the extended warranty.

Lennox Furnace Lineup & Pricing

Lennox organizes its furnaces into three product lines, each with a distinct positioning: Signature (SL-series) at the top, Elite (EL-series) in the middle, and Merit (ML-series) at the value end. Installed prices below are derived from owner-reported figures on our platform and typical contractor quotes.

Top-Tier Signature Collection (97–99% AFUE)

Installed price range: $8,000–$12,000+

The SLP99V is the flagship — a 99% AFUE modulating furnace with a variable-speed ECM blower, currently the highest AFUE rating available on a residential gas furnace in North America. Paired with an iComfort thermostat, it adjusts output in 1% increments to hold target temperature tightly. The SL297NV sits just below at 97.5% AFUE with a two-stage burner — essentially flagship-tier efficiency and comfort without the modulating burner premium.

Elite Collection (96–97% AFUE)

Installed price range: $5,500–$8,500

The EL297V and EL297E are the 97% AFUE two-stage options in the Elite line. The EL296V and EL296E deliver 96% AFUE two-stage performance at a slightly lower price point. The single-stage Elite models — the EL196E, EL195NE, and their low-profile "EK" variants (EL196EK, EL195NEK) — all ship with variable-speed ECM blowers, making them unusual in the single-stage market.

Merit Collection (93–96% AFUE)

Installed price range: $4,000–$6,500

The ML296V is the lone two-stage Merit model, at 96% AFUE. The single-stage Merit lineup — ML196E, ML196EK, ML193E, ML193EK — covers 93–96% AFUE and pairs the single-stage burner with a variable-speed ECM blower. The Merit line is the sensible choice for Lennox buyers who want the brand and dealer relationship without paying for Signature-tier refinement.

Oil Furnaces

Lennox is one of a shrinking number of major brands still producing oil furnaces. The SLO185V delivers 87% AFUE from the Signature line, and the ELO183 offers 83% AFUE at a lower price. Both are worth considering for homes still on oil heat, particularly in the Atlantic provinces and parts of rural Ontario and Quebec.

US-Market-Only Gas Models (80% AFUE)

Lennox also offers several 80% AFUE gas models — the SL280V, SL280NV, EL280E, EL180NE, EL180NEK, ML180V, ML180E, and ML180EK. These don't meet the 95% AFUE minimum for new residential installations in most Canadian provinces and are primarily sold in the US market.

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Warranty Analysis

Lennox's warranty structure is genuinely tiered — the Signature, Elite, and Merit product lines each carry different base terms, so comparing at the product-line level is more useful than comparing model by model.

The warranty terms

All 95%+ AFUE Elite and Signature gas models carry a lifetime heat exchanger warranty when registered within the required window. The key variations are in parts coverage and extended terms:

Labour warranty is not included on any current Lennox model, and no Lennox furnace currently offers a unit replacement term — a notable gap compared to Carrier, Bryant, KeepRite, and most of the ICP and Daikin families.

Registration is required — and the window is tight

To activate the extended parts term and (on applicable models) the lifetime heat exchanger coverage, the furnace must be registered within 60 days of installation. That's noticeably tighter than the 90-day window used across the ICP family (Carrier, Bryant, KeepRite, Heil, Tempstar). Missing the 60-day window drops parts coverage to the 5- or 10-year base term and, on 95%+ Elite/Signature gas models, shortens the heat exchanger term to 20 years instead of lifetime.

Registration is a recurring friction point in owner feedback. A few owners specifically flagged unhappiness with the registration-to-activate structure, with one calling the requirements "prohibited in some jurisdictions." Confirm with your installer that registration has been completed within the 60-day window and keep the confirmation email on file.

Note for Quebec residents: Quebec consumer protection law prohibits conditioning warranty coverage on registration. You automatically receive the full extended warranty terms without needing to register — the registration deadline doesn't apply.

How it compares

Against Carrier and Bryant, Lennox's 95%+ heat exchanger coverage is comparable (both offer lifetime), but Carrier and Bryant include unit replacement terms on their premium models and offer a more forgiving 90-day registration window.

Against Goodman and Amana, Lennox's Signature 10-year parts term is stronger than the 2-year base Goodman/Amana offer before registration, but Goodman and Amana add unit replacement coverage that Lennox does not.

For value-minded buyers, Lennox's Merit line carries weaker warranty coverage than competing premium mid-range options at similar price points.

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Notable Features

SLP99V modulating performance

What it is: Lennox's flagship 99% AFUE modulating furnace, which adjusts gas input in 1% increments (65–100% of capacity) matched to a variable-speed ECM blower.

The practical benefit: The tightest temperature control available in the residential gas furnace market, near-silent operation at part load, and the lowest achievable gas bills for homeowners who are heating through long, cold winters.

Worth knowing: The efficiency gap between the 99% SLP99V and a 97.5% SL297NV is narrow in dollar terms — the SLP99V's case is built more on comfort precision than on fuel savings. If the $1,500–$3,000 upgrade cost is a stretch, the SL297NV is often the more sensible pick.

iComfort® communicating thermostat ecosystem

What it is: Lennox's proprietary communicating thermostat platform (S30, S40, and Signature Stat models) that coordinates furnace staging, blower speed, IAQ accessories, and zoning over a single data bus.

The practical benefit: Fine-grained comfort tuning, Wi-Fi and app control, integrated indoor air quality management, and richer diagnostics for service calls. Well-regarded by owners who've used it.

Worth knowing: iComfort components are proprietary — replacement boards and control modules cost more than conventional equivalents, and service typically requires a Lennox dealer. On single-stage or Merit-tier equipment, a standard smart thermostat delivers most of the practical value at a fraction of the cost.

Variable-speed ECM blower across the entire gas lineup

What it is: Every current Lennox gas furnace — including the single-stage Merit models — ships with a variable-speed ECM blower rather than a fixed-speed or multi-tap PSC motor.

The practical benefit: Lower electricity use in continuous fan mode and smoother airflow transitions. On a single-stage Merit unit this is unusually generous — most competitors reserve variable-speed blowers for mid-range and premium tiers.

Worth knowing: The efficiency advantage is most noticeable in homes that run the blower for air circulation or filtration between heating cycles.

Add-Ons & IAQ Accessories

Lennox's IAQ lineup ties closely to the iComfort ecosystem — Healthy Climate media filters, PureAir air purification (UV + catalyst), bypass and powered humidifiers, and HRV/ERV units. When paired with an iComfort thermostat, several of these accessories report status and runtime to the app, which is a genuine integration advantage.

Bundling IAQ with the furnace install typically reduces total cost. Specific accessory recommendations depend on home tightness, regional climate, and allergy sensitivity more than on which Lennox furnace you choose.

About Lennox

Lennox International was founded in 1895 by Dave Lennox in Marshalltown, Iowa, originally producing riveted-steel furnaces. The company is headquartered in Richardson, Texas, trades publicly on the NYSE (ticker: LII), and operates as a standalone HVAC manufacturer — not part of a multi-brand conglomerate like Carrier Global or Daikin. Lennox also owns the Armstrong Air, AirEase, Aire-Flo, and Concord brands for the wholesale-distribution channel, but the Lennox-branded lineup is its own distinct product line sold exclusively through authorized Lennox dealers.

Frequently Asked Questions

Is Lennox a good furnace brand?

Yes — across 264 owner reviews on our platform, Lennox furnaces average about 4.6 out of 5, with roughly nine in ten ratings positive. Reliability, quiet operation, and energy efficiency are the most commonly cited strengths. Lennox's flagship SLP99V offers the highest AFUE rating available in the category, and the 95%+ AFUE Elite and Signature models carry a lifetime registered heat exchanger warranty. The main trade-off is premium pricing.

How long does a Lennox furnace last?

With regular annual maintenance, a Lennox furnace typically lasts 15–20 years, in line with the broader gas furnace category. We have owner reviews on our platform referencing Lennox units running reliably after 18 and 21 years, though as with any furnace, lifespan depends heavily on installation quality, ductwork sizing, and regular servicing. Lennox's lifetime registered heat exchanger warranty on 95%+ Elite and Signature gas models reflects the brand's confidence in the core component's durability.

How much does a Lennox furnace cost installed?

Based on owner-reported prices on our platform, Lennox furnaces average around $6,600 installed — roughly 20–30% above the category average. Entry-level single-stage Merit models start around $4,000, mid-range Elite two-stage models land in the $5,500–$7,500 range, and the flagship SLP99V typically installs for $9,000–$12,000+ depending on home size and installation complexity. Lennox pricing runs noticeably higher than equivalent Carrier, Bryant, or ICP-family alternatives.

What's the difference between Lennox Signature, Elite, and Merit?

Signature (SL-series, SLP-series, SLO-series) is the flagship line with the 10-year base parts warranty, the highest-efficiency modulating and two-stage models, and full iComfort integration. Elite (EL-series) is the mid-tier line with 5-year base parts coverage but the same lifetime registered heat exchanger term on 95%+ gas models, and it covers a wide efficiency range from 95% single-stage up to 97% two-stage. Merit (ML-series) is the value line with 5-year base parts and a 20-year (not lifetime) heat exchanger term, and it's positioned to compete with other brands' mid-range options.

Does Lennox offer a unit replacement warranty?

No — unlike Carrier, Bryant, KeepRite, Goodman, and several other major brands, no current Lennox furnace model includes a unit replacement term in its warranty. Coverage is limited to parts replacement (10 or 12 years with registration) and the heat exchanger itself (lifetime on most 95%+ Elite and Signature gas models, 20 years otherwise). If unit replacement coverage is important to you, it's a meaningful gap to factor into the purchase decision.