A Lennox gas furnace typically costs $3,500-$12,000 installed, with many standard replacement jobs near $6,500. The final quote depends mainly on furnace capacity and efficiency, installation labor, venting or duct changes, and local labor rates.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Installed furnace | $3,500 | $6,500 | $12,000 | Existing home, standard replacement |
| Equipment only | $1,800 | $3,500 | $5,500 | Furnace price before installation |
| Installation labor | $800 | $1,600 | $3,000 | More for difficult access or system changes |
| Annual fuel efficiency | 80% AFUE | Up to 96% AFUE | Up to 98% AFUE | Model availability varies |
What a Lennox furnace replacement usually costs
For a straightforward replacement, homeowners often pay $4,500-$8,000 for a midrange Lennox furnace and installation. A basic 80% AFUE unit with existing compatible venting may land near $3,500-$5,500, while a high-efficiency variable-speed model can bring the total to $8,000-$12,000 or more.
Equipment-only prices commonly run $1,800-$5,500, depending on model and capacity. These figures exclude labor, old-furnace removal, permits, and any duct, vent, or electrical work. Assumptions: existing ductwork is usable, access is normal, and no major code upgrades are needed.
For a typical replacement, use about $6,500 as a planning midpoint, then adjust for efficiency, site work, and location. Contractor pricing can differ because equipment discounts, warranty terms, and included services vary.
How equipment, labor, and venting shape the quote
An installed quote combines the furnace, setup work, and any required changes. The ranges below describe common U.S. replacement pricing; individual items may be bundled rather than listed separately.
| Quote item | Typical range | What affects the charge | Common unit rate |
|---|---|---|---|
| Lennox furnace | $1,800-$5,500 | Capacity, AFUE, blower, model tier | $1,800-$5,500 per unit |
| Labor and startup | $800-$2,500 | Crew time, access, commissioning | $75-$150 per labor hour |
| Venting or flue changes | $300-$1,500 | High-efficiency condensate and vent route | $15-$40 per linear ft for basic vent material |
| Removal and disposal | $150-$500 | Old equipment handling and haul-away | $150-$500 per furnace |
| Permit and inspection | $50-$400 | City or county requirements | $50-$400 per job |
A two-person crew may complete a simple changeout in 6-10 hours, but moving equipment, adapting a plenum, or installing new venting can add time. Ask whether the estimate includes startup testing, thermostat setup, and disposal.
Labor and system modifications can add more to the total than a small difference in furnace purchase price.
Which capacity and AFUE choices raise Lennox pricing?
Capacity is usually measured in BTUs per hour. Many single-family homes use furnaces rated around 40,000-100,000 BTU, but a contractor should size equipment using a heat-loss calculation rather than simply matching the old unit. An incorrectly oversized furnace may cost more upfront and can cycle frequently.
Efficiency also affects both price and installation details. An 80% AFUE furnace often costs less and may use an existing metal flue. A 90%-plus AFUE model typically needs appropriate PVC venting and a condensate drain. Higher-efficiency options can add roughly $800-$2,500 compared with a basic model, depending on configuration.
Blower type and controls matter as well. Single-stage equipment generally sits at the lower end; two-stage or variable-speed models often cost more but offer more operating settings. Confirm that the quoted model’s capacity, AFUE rating, and venting requirements match the home before comparing totals.
What installation labor includes and when it takes longer
A standard changeout usually includes disconnecting the old furnace, setting and connecting the new unit, adapting nearby connections, and testing operation. Basic labor often falls around $800-$2,500; a full new installation or substantial mechanical changes may push labor and related work above $3,000.
Basement stairs, attic placement, tight mechanical rooms, or long equipment-carry distances can increase crew time. A new return-air path, gas-line adjustment, electrical correction, or condensate pump may add $200-$1,500 or more, depending on scope. Permit inspections can also require corrections before the job is closed.
Compare the written scope, not just the labor line: two quotes may include very different venting, removal, and startup work.
How U.S. location changes a Lennox furnace estimate
Labor and permitting make installed prices vary by region. In lower-cost rural markets, a comparable replacement may run about 10%-20% below the national midpoint. Major coastal cities and high-cost metro areas can be 15%-30% above it, especially when contractor demand, parking, or access raises job time.
Climate also affects sizing and equipment selection. Colder areas may need greater heating capacity, while homes in milder regions can sometimes use smaller units. Local gas and electrical codes may require venting, shutoff, or wiring changes that are not needed in another jurisdiction. Use local written quotes for budgeting because national ranges cannot account for each home’s code and labor conditions.
When removal, duct repair, or code work adds expense
Old-furnace removal is often included, but some contractors charge $150-$500 separately. Duct sealing or small repairs may cost $200-$1,000; replacing sections of ductwork can be substantially more. A condensate pump, new thermostat, or gas connector can add about $100-$600, depending on the item and installation.
Older homes may need electrical grounding, combustion-air provisions, or vent changes to meet current requirements. These are not automatic charges on every job. Request an itemized explanation, and ask the contractor to distinguish required safety or code work from optional upgrades.
Unexpected work should be priced and approved before installation rather than added as an unexplained allowance.
Ways to lower the replacement price without oversizing
Get at least three itemized bids based on the same furnace capacity and comparable AFUE, blower, warranty, and included work. Ask each contractor to identify the exact Lennox model number and whether the price includes permits, removal, venting, controls, and startup. A lower equipment price may not represent a lower finished-job cost.
Keep usable ductwork and venting when the contractor confirms they are safe and compatible. Avoid paying for a premium efficiency level solely on the promise of savings; compare the added purchase price with expected fuel use and local gas rates. Replacing in advance of an emergency may also allow more time to compare bids and avoid rush charges.
Do not choose a smaller furnace just to cut the quote. Proper sizing affects comfort and operation, so request the calculation behind the recommended capacity. The most reliable savings come from controlling optional scope while retaining correctly sized equipment and required safety work.