Lennox Merit vs Elite vs Signature comes down to how many stages you are paying for: Merit is mostly single-stage equipment on an ordinary thermostat, Elite adds two-stage furnaces and variable-capacity air conditioners, and the Dave Lennox Signature Collection is modulating furnaces and fully variable outdoor units built around Lennox's communicating thermostat. For most two-storey Ontario houses, the Elite two-stage furnace is the tier to buy. Step up to Signature only when the house has a comfort problem that two stages will not fix, and drop to Merit for a small house, a rental or a short hold.
What Changes at Each Lennox Tier
The burner and the blower change; the efficiency barely does. Every Lennox furnace that meets the 95% AFUE federal minimum is a condensing model, and the range tops out at 99%, so the tiers are really a choice about staging, airflow and controls.
- Merit (ML): the entry tier. The ML196E is a single-stage furnace with a constant-torque blower at up to 96% AFUE. Merit air conditioners are mainly single-stage, with a two-stage model in the ML17KC2, and Lennox now lists a two-stage variable-speed furnace, the ML297V, inside Merit as well.
- Elite (EL): the middle tier. It runs from the single-stage EL196E through the two-stage EL296E and EL297E to the two-stage, variable-speed EL296V and EL297V. Elite air conditioners include single-stage models and the variable-capacity EL18KCV and EL22KCV.
- Dave Lennox Signature Collection (SL): the top tier. The SLP99V is a modulating, variable-speed furnace at up to 99% AFUE, and the SL25KCV is a variable-capacity air conditioner. Heat pumps follow the same pattern.
The tiers overlap at the edges, which is why the series name alone does not tell you what you are buying. A two-stage Merit and a two-stage Elite differ in blower, cabinet and warranty more than in how they heat. Our explainer on single-stage, two-stage and modulating furnaces covers what each stage type does in a house.
Controls: Which Tiers Need the Lennox Thermostat
Only the top of the range depends on Lennox's own control. Everything in Merit and the staged Elite furnaces will run on a conventional 24 V thermostat, including most smart thermostats with a C-wire.
- Merit: any 24 V thermostat. No Lennox control needed.
- Elite furnaces: a conventional two-stage thermostat works. The EL297V is also built to pair with the Lennox S40 smart thermostat if you want a communicating setup.
- Elite variable-capacity air conditioners: the EL18KCV can run without the S40 and becomes part of a communicating system when paired with a digital furnace and that thermostat.
- Signature furnace: the SLP99V works with a conventional thermostat, but its diagnostics and finest control come with the S40.
- Signature outdoor units: the SL25KCV is designed to pair with the S40 as a fully communicating system. Plan on the Lennox thermostat.
The S40 replaces the earlier iComfort S30, and both are Lennox-only controls. Once a system is communicating, an ecobee or a Nest cannot take over without losing the variable-capacity behaviour, and a replacement thermostat ten years on has to be Lennox's current model. Decide whether you are comfortable with that before paying for the top tier.
How to Read the Model Number on a Quote
The model number tells you the tier, the staging and the blower in the first six or seven characters. If a quote says only 'Lennox 96% furnace', ask for the full number before comparing it with anything.
- First two letters: ML is Merit, EL is Elite, SL is Signature.
- First digit on a furnace: on most models 1 is single-stage and 2 is two-stage. EL196E is single-stage; EL296V is two-stage. Confirm on the specification sheet.
- Next two digits on a furnace: the AFUE class, such as 96 or 97. SLP99V is the 99% modulating model.
- Final letter on a furnace: E is the constant-torque blower, V is variable-speed.
- On an air conditioner, the ending gives the staging: C1 is single-stage, C2 is two-stage, CV is variable-capacity. ML17KC2 is a two-stage Merit; EL18KCV is a variable-capacity Elite.
- The characters after that give the configuration, the heating input and the cabinet size, which should match the heat-loss calculation, not the old furnace.
Check the outdoor unit and the indoor coil numbers the same way. A Signature furnace quoted with a Merit air conditioner is a legitimate combination, but it is not a Signature system, and it should not be priced like one.
Free quotes, written pricing.
Where the Price Jump Is Not Matched by a Comfort Gain
The step from Merit to an Elite two-stage furnace is the one most houses feel. Low fire runs longer, the temperature swing between cycles shrinks, and the upstairs bedrooms of a two-storey even out. A furnace that used to blast and stop becomes one you barely notice.
The step from Elite to Signature is where money is most often wasted. These are the cases where the upgrade does not pay back in comfort.
- A compact bungalow or townhouse with short duct runs: a single-stage or two-stage furnace already holds it steady.
- A house with undersized return air: a modulating furnace or variable-capacity outdoor unit cannot use its range against high static pressure. Fix the ducts first.
- A Signature furnace wired to a basic thermostat: you have bought modulation and are not using most of it.
- Buying for the AFUE number: going from 97% to 99% trims a couple of percent off the heating portion of the gas bill.
- A house you expect to sell within five years.
- Single-stage furnace, standard replacement: the lower end of the $4,300–$7,000 installed band
- Two-stage furnace with a variable-speed blower: where most jobs land, $4,500–$6,500
- Signature-level furnace: typically $500–$1,500 above an equivalent value-brand model, plus the S40 if it is not already included
Those ranges assume a like-for-like swap with sound venting; the pricing page has the rest.
Warranty Differences by Tier
Coverage gets longer as you move up, and registration changes it at every level. Lennox's product pages list the following; your certificate is the final word.
- Merit ML196E: 5 years on parts and 20 years on the heat exchanger, with extended coverage offered through registration.
- Elite: 5 years on covered components and 10 years on air conditioner compressors as standard, a 10-year extended limited warranty with registration, and a limited lifetime heat exchanger warranty on the EL297V.
- Signature: 10 years on covered components, and a 20-year or lifetime limited warranty on the heat exchanger depending on the furnace.
- All tiers: the factory warranty covers parts only. Registering lets the owner select up to 3 years of labour coverage.
Verdict: Which Lennox Tier for Which House
- Merit: a bungalow, a townhouse, a rental or a house you will sell soon. Reliable heat on any thermostat at the lowest price.
- Elite two-stage with a variable-speed blower: the typical two-storey detached house in Burlington, Oakville, Milton or on the Hamilton Mountain. This is the tier we recommend most often.
- Signature: a large or three-level house with uneven floors, an owner staying 15 years or more, or a hybrid system built around a variable-capacity heat pump, bought as a complete matched system with the S40.
We service Lennox equipment at every tier, and our Lennox furnace repair page covers the faults each generation tends to show. For how Lennox stacks up against another premium brand, read Lennox vs Trane. When you are ready for numbers, our furnace installation quotes list the full model number, the thermostat and the warranty registration; book a visit and we will measure the house first.
Frequently asked questions
Is Lennox Elite worth it over Merit?
For a two-storey house, usually yes, provided the Elite model quoted is a two-stage furnace such as the EL296V. The benefit is longer, quieter low-fire cycles and more even temperatures between floors. If the Elite on your quote is the single-stage EL196E, you are paying mostly for the series name, and the single-stage Merit will heat the house the same way.
Does a Signature furnace work without the Lennox S40 thermostat?
The SLP99V will run on a conventional thermostat, so the house will be heated. What you give up is the communicating link that lets the thermostat read the equipment's sensors and manage capacity precisely. Signature variable-capacity outdoor units are a different matter: they are designed around the S40, and that thermostat should be on the quote.
Can I pair an Elite furnace with a Merit air conditioner?
Yes. On conventional, non-communicating equipment the furnace and the air conditioner are controlled separately by the thermostat, so tiers can be mixed. The indoor coil must be a rated match for the outdoor unit, and the furnace blower must suit the cooling airflow. Mixing stops making sense once either half is a communicating, variable-capacity model.
What do the K and X mean in Lennox air conditioner model numbers?
On the units we see, the K marks the current generation built for the newer refrigerant, as in ML17KC2 or EL18KCV, while X appears on the earlier R-410A generation, as in ML14XC1. The letters that follow still give the staging. If a quote lists an X model, ask whether it is remaining stock and how that affects future refrigerant service.