Lennox Furnace Guide: Prices, Cost, Models, Reviews, Warranty, Efficiency Ratings, and Filter Recommendations
October 23, 2026
How Much Does A Lennox Furnace Cost?
A new Lennox gas furnace typically costs $3,000 to $9,500 installed. Your price depends on the tier you choose and how much venting or ductwork your home needs.
- Merit: $3,000 to $5,500, rated 80% to 96% AFUE
- Elite: $4,900 to $6,500, rated up to 97% AFUE
- Dave Lennox Signature: $5,600 to $9,500, rated 80% to 99% AFUE
The tiers overlap on price, so compare dealer quotes by model number. Whichever Lennox you pick, it needs a clean, correctly sized filter. Take the quick quiz below to find yours.
Find Your Furnace Filter Match
Answer a few quick questions and we'll match you to the right filter for your furnace.
A Lennox furnace typically costs between $3,000 and $9,500 installed, depending on the tier, the efficiency rating, and how much venting or ductwork your home needs. Lennox International builds three gas furnace tiers, the Merit Series, the Elite Series, and the Dave Lennox Signature Collection, rated from 80% to 99% AFUE (the share of fuel that becomes heat). The Filterbuy team reviewed Lennox's current product and warranty pages, then matched Lennox filter part numbers to the filters Filterbuy makes.
TL;DR
Lennox gas furnaces cost roughly $3,000 to $5,500 installed for the Merit Series, $4,900 to $6,500 for the Elite Series, and $5,600 to $9,500 for the Dave Lennox Signature Collection. The SLP99V tops the lineup at up to 99% AFUE.
Key Takeaways
Lennox sells three tiers: Merit, Elite, and Dave Lennox Signature.
Lennox gas furnaces range from 80% AFUE to up to 99% AFUE on the SLP99V, which adjusts its flame in small steps.
Base parts coverage is 5 years on Merit and Elite and 10 years on Signature, and registration extends it.
New indoor (non-weatherized) gas furnaces made from December 18, 2028 must reach 95% AFUE.
How Much Does a Lennox Furnace Cost?
Your Lennox price depends mostly on the tier and on how much work your home needs. Merit Series furnaces sit at the low end, and Dave Lennox Signature Collection furnaces cost the most. Venting and ductwork changes can move a quote by thousands.
Lennox Furnace Collections Compared
Installed prices reflect a published installer cost guide and vary by region and installation scope.
The tiers overlap on price. A fully equipped Merit install can cost more than a basic Elite install. So compare quotes by model number and scope, and don't shop by tier name alone.
For labor costs and rebates, see our furnace replacement price guide.
Which Lennox Gas Furnace Models Are Available in 2026?
The current Lennox gas furnace lineup runs from the 80% AFUE ML180V to the 99% AFUE SLP99V. The EL297V leads the Elite Series at up to 97% AFUE.
Lennox Gas Furnace Models Compared
AFUE figures are maximum ratings from Lennox as of October 2026. Heat shows single-stage (1-stage), two-stage (2-stage), or modulating heat.
A "K" at the end of a model number, such as SLP99VK, means the furnace includes a refrigerant detection system for air conditioners that use newer, mildly flammable A2L refrigerants. An "N", as in the SL297NV, marks an ultra-low nitrogen oxide (NOx) version sold in parts of California.
Lennox's spec pages had errors when we checked them in October 2026. The SL297NV page listed both 97% and 97.5% AFUE. The ML180V page showed "up to 97% AFUE" next to an 80% spec. Ask your dealer for the certified rating of the exact model in your quote.
Lennox Furnace Efficiency Ratings Explained
AFUE, or Annual Fuel Utilization Efficiency, is the share of fuel a furnace turns into heat for your home over a year. A 97% AFUE Lennox furnace delivers about 97 cents of heat per dollar of gas, while an 80% AFUE model delivers about 80 cents.
Heating homes accounted for 42% of energy consumption in the U.S. residential sector, according to the U.S. Energy Information Administration.
ENERGY STAR certifies gas furnaces at 97% AFUE or higher in the U.S. North and 95% AFUE or higher in the U.S. South, according to the ENERGY STAR furnace criteria. The Lennox SLP99V, SL297NV, and EL297V are ENERGY STAR certified.
New indoor (non-weatherized) gas furnaces manufactured on or after December 18, 2028 must reach at least 95% AFUE under the furnace standard finalized by the U.S. Department of Energy, which projects $1.5 billion in annual utility savings. In June 2026, the U.S. Supreme Court sent a legal challenge back to the D.C. Circuit for reconsideration, and the rule stays in effect meanwhile.
We also found the EL297V product page still listing federal Section 25C tax credit eligibility. That credit ended for equipment placed in service after December 31, 2025, as the IRS Form 5695 instructions confirm.
What Does the Lennox Furnace Warranty Cover?
Base parts coverage is 5 years on Merit and Elite furnaces and 10 years on Signature furnaces. Registration within 60 days of installation adds an extended limited warranty at no charge.
After registration, Merit and Elite owners choose 10 years of parts coverage (Option A) or 7 years of parts plus 3 years of labor (Option B). Signature owners choose 12 years of parts or 10 years of parts plus 3 years of labor. Heat exchanger coverage is 20 years on most Merit furnaces and 80% AFUE Signature models, and limited lifetime on condensing Elite and Signature models.
Which option should you pick? Option A gives you the longer parts term. Option B trades 3 years of parts coverage for 3 years of labor coverage right after installation, when you're paying a dealer for any early repair. Keep your installation paperwork and filter change records.
Lennox Furnace Reviews: Strengths and Trade-Offs
Lennox furnaces stand out for high efficiency and quiet insulated cabinets. The main drawbacks are dealer-only pricing and Lennox-specific controls.
Strength: steady comfort. Two-stage and modulating models run at low output most of the time.
Strength: low-emission options. Lennox rates the SL297NV at up to 65% lower NOx than standard low NOx furnaces.
Trade-off: dealer-only purchase. Price and installation quality depend on the authorized dealer you hire.
Trade-off: proprietary controls. Some SLP99V comfort settings require a compatible Lennox smart thermostat.
Questions to Ask Your Lennox Dealer Before You Sign
Ask these six questions before you sign.
What is the exact model number, and what is its certified AFUE rating?
Did you size the furnace with a Manual J load calculation, the room-by-room heating math?
Does the price include new PVC venting or a condensate drain?
Who registers the furnace, and is it Option A or Option B?
For an 80% AFUE model, how does the 2028 federal 95% AFUE rule affect future replacement?
Which filter size or Lennox part number does the system use?
Which Air Filter Does a Lennox Furnace Use?
Finding your size takes about a minute. Most Lennox gas furnaces take either a 1-inch filter in a return grille or filter rack, or a 3- to 5-inch filter in a Lennox media cabinet, the filter housing beside the blower. Check the size printed on your old filter first. Media cabinets also list a Lennox part number on the label. Filterbuy makes compatible replacements for these part numbers:
X0582: 16x20x5
X0581, X5427: 16x25x3
X0583, X6670, HCF16-10: 16x25x5
X6664, X6666: 17x26x4
X0585, X8305, X8308: 20x20x5
X8790: 20x21x5
X0586, X6673, X5426: 20x25x5
X0587, X5428: 20x26x5
The size on the label is the ordering name. The actual filter is cut slightly smaller by design, and that clearance is what makes it fit. Filterbuy filters are cut, pleated, and framed to order in our own US plants. Each size above comes in MERV 8, 11, and 13, and the 16x20x5 comes in MERV 8 and 11. If your size isn't listed, Filterbuy makes custom air filters cut to the eighth of an inch.
MERV, or Minimum Efficiency Reporting Value, rates how much a filter captures on a 1 to 16 scale. MERV 8 air filters are the standard choice for most homes. MERV 11 air filters are made for allergy sufferers and homes with pets or pollen. MERV 13 air filters are the pick for homes dealing with smoke.
The EPA recommends filters rated at least MERV 13 in its guidance on MERV ratings. Whichever tier you choose, check your Lennox furnace manual for compatibility, the same way you'd confirm the size. Our guide to MERV 8 vs MERV 11 vs MERV 13 filters compares all three.
Filterbuy is not affiliated with or endorsed by Lennox International. Lennox is named here only to show compatibility.
"Most people get stuck on the size, and they don't need to. Look at the label on your Lennox media cabinet, find the part number, and you've got your filter. Then pick the MERV tier that fits your home."
Michelle Wan, Brand Manager and Air Quality Writer, Filterbuy
The U.S. Consumer Product Safety Commission advises putting a carbon monoxide (CO) alarm with battery power or battery backup on each level of your home and outside sleeping areas. Pair them with a yearly furnace inspection.
Supporting Statistics
400+ deaths a year from carbon monoxide. Unintentional CO poisoning not linked to fires kills more than 400 Americans each year. More than 100,000 people visit an emergency department. Gas furnaces are a listed CO source. Source: Centers for Disease Control and Prevention.
27,900 heating fires in 2023. Heating was the third leading cause of U.S. residential building fires that year. Source: U.S. Fire Administration.
1.23 million gas furnaces shipped. U.S. shipments reached 1,232,653 units from January through May 2026. Source: AHRI shipment data.
How We Researched This Guide
We reviewed Lennox's current furnace product pages and warranty terms on October 23, 2026.
We checked each claim against federal sources, including DOE, ENERGY STAR, IRS, EPA, CPSC, and CDC.
We took installed price ranges from a published installer cost guide.
We matched Lennox media cabinet part numbers to the Filterbuy filter catalog.
David Clark, Licensed HVAC Technician, reviewed the technical content.
Frequently Asked Questions About Lennox Furnaces
Are Lennox Furnaces Good?
Yes, for buyers who value efficiency and warranty length. Reliability depends most on correct sizing and installation.
How Long Does a Lennox Furnace Last?
A Lennox gas furnace commonly lasts 15 to 20 years with annual maintenance and regular filter changes. The InterNACHI home life expectancy chart lists furnaces at 15 to 25 years. See when to replace a furnace for warning signs.
Can I Buy a Lennox Furnace Online?
No. Lennox sells furnaces through authorized dealers who size and install the equipment. You can buy Lennox-compatible replacement air filters online from Filterbuy.
How Often Should I Change the Filter in My Lennox Furnace?
Change a 1-inch Lennox furnace filter every 1 to 3 months. Thicker media filters last longer, so you'll follow your Lennox manual for those. Our furnace filter replacement guide walks through each step, and an air filter subscription ships replacements on your schedule.
Glossary
A2L Refrigerant: A newer class of mildly flammable air conditioner refrigerant.
AHRI: The Air-Conditioning, Heating, and Refrigeration Institute, the HVAC trade group that reports shipment data.
CO (Carbon Monoxide): An odorless gas produced by fuel-burning appliances, including gas furnaces.
Filterbuy: An air filter manufacturer that makes pleated HVAC and furnace filters in MERV 8, 11, and 13.
AFUE (Annual Fuel Utilization Efficiency): The percentage of fuel a furnace converts into usable heat over a year.
Condensing Furnace: A 90%+ AFUE furnace that recovers exhaust heat and needs PVC venting.
ENERGY STAR: The U.S. EPA program certifying furnaces that meet regional AFUE thresholds.
Manual J: The industry load calculation for sizing a furnace.
Media Cabinet: A housing beside the blower that holds a 3- to 5-inch filter.
MERV (Minimum Efficiency Reporting Value): A 1 to 16 rating of how well a filter captures airborne particles.
Modulating Furnace: A furnace that adjusts its flame in small steps.
NOx (Nitrogen Oxides): Combustion gases that low NOx furnaces reduce.
Two-Stage Furnace: A furnace with low and high heat settings.
Find the Right Filter for Your Lennox Furnace
A clean, correctly sized filter protects your home's air and your Lennox furnace. Find your media cabinet part number, then shop Filterbuy's Lennox-compatible air filters in MERV 8, 11, and 13, with fast and free 2-day delivery to most US states.