A Lennox 100,000 BTU furnace typically costs $4,500-$10,000 installed, with many standard replacements near $7,000. The final price depends on efficiency, single- or two-stage operation, venting, ductwork, local labor, and whether the existing furnace must be removed.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Furnace equipment | $2,000 | $3,400 | $5,500 | Model, efficiency, and features affect price |
| Installed replacement | $4,500 | $7,000 | $10,000 | Standard access and compatible connections |
| Installed with significant upgrades | $7,000 | $9,500 | $13,000+ | May include vent, gas-line, or duct changes |
| Heating capacity | 100,000 Btu/h | 100,000 Btu/h | 100,000 Btu/h | Confirm sizing with a load calculation |
Installed Lennox 100,000 BTU furnace price
For a straightforward swap, a 100,000 Btu Lennox furnace commonly totals $4,500-$10,000, including equipment, installation, basic connections, and removal of the old unit. A reasonable planning average is about $7,000. Lower quotes generally involve a basic, single-stage model and uncomplicated access; higher quotes may reflect a more efficient or modulating model, premium controls, or required system work.
Equipment-only pricing is often about $2,000-$5,500 before installation, tax, and any accessories. Compare quotes with the same model, AFUE rating, warranty, and included work rather than comparing brand names alone.
Assumptions: U.S. residential replacement, standard natural-gas setup, average access, and no major duct replacement.
What the equipment and installation quote pays for
A furnace estimate should separate the appliance from labor and job-specific charges. A low equipment price may not include disposal, a new vent, permits, or commissioning. Ask whether the contractor will test airflow and gas pressure and verify the furnace is operating to manufacturer specifications.
| Quote component | Typical range | Pricing basis | What can change it |
|---|---|---|---|
| Lennox furnace | $2,000-$5,500 | Per unit | Efficiency, staging, and controls |
| Installation labor | $1,200-$3,000 | Per job | Access and connection changes |
| Removal and disposal | $150-$500 | Per old unit | Haul distance and disposal fees |
| Permit and inspection | $50-$400 | Per project | Local requirements |
| Venting or accessories | $200-$1,800 | Per job | Vent type, thermostat, and drain |
These ranges are estimates, not a fixed Lennox price list; contractor package pricing can combine several lines. Request an itemized quote that identifies model numbers and exclusions.
How AFUE and staging change the 100,000 Btu price
Efficiency and operating features can move a quote by hundreds or several thousand dollars. A basic single-stage furnace may fall toward the lower end, while two-stage or variable-capacity equipment usually costs more and may require compatible controls. Compare AFUE, the annual fuel utilization efficiency rating, alongside the installed price; higher AFUE means more of the fuel’s energy becomes heat, but savings depend on fuel prices, climate, and usage.
Venting is another model-specific expense. A high-efficiency condensing furnace commonly uses plastic intake and exhaust pipes and needs a condensate drain; adapting an older metal-vent setup can add roughly $300-$1,500. Confirm that the quoted model can use the home’s existing vent route before treating it as a simple replacement.
How many labor hours does a furnace swap take?
A like-for-like replacement often takes a two-person crew about 6-10 hours. Relocating the furnace, correcting venting, modifying the plenum, or adding a condensate pump can extend the job to 1-2 days. Labor commonly accounts for $1,200-$3,000 of a typical installation, with higher rates in expensive metro areas or for difficult access.
Ask whether startup, thermostat setup, permit coordination, and a post-installation test are included. A written scope helps reveal whether a lower bid assumes fewer labor tasks.
Regional labor rates can shift the installed total
Prices in high-cost coastal metros and parts of the Northeast can run about 10%-25% above a national midrange estimate. Smaller cities and rural markets may come in 5%-15% lower, although long travel distances or limited contractor availability can erase the difference. These percentages are broad comparisons; local quotes depend on the season, permit rules, and equipment supply.
For example, a $7,000 midrange installation could be roughly $7,700-$8,750 in a higher-cost market or $5,950-$6,650 in a lower-cost market, before unusual site work. Compare at least two local bids with matching equipment and written scope.
When venting, gas lines, or ducts add more
Extra work can raise a standard replacement by $500-$3,000 or more. Common additions include a new flue route, a gas shutoff or connector, electrical updates, a condensate drain, and plenum adjustments. Major duct repairs or replacement are separate work and may add several thousand dollars, depending on the number of runs and access.
Capacity also deserves checking: 100,000 Btu/h is not automatically right because the old furnace had that rating. A load calculation considers the home’s insulation, windows, air leakage, and local design temperature. Oversizing can contribute to short cycling and uneven comfort, so request sizing documentation.
Repair or replace an aging Lennox furnace
A repair may cost $150-$600 for common service work, while major components such as a blower motor or control board can bring a bill to roughly $500-$1,500. A cracked heat exchanger or repeated expensive failures may make replacement worth pricing, but diagnosis and safety inspection should come first. Furnace age, repair history, parts availability, and warranty status all affect the comparison.
When comparing repair with a new furnace, include expected near-term service costs, not just the purchase price. For a relatively young furnace with a limited fault, a documented repair estimate may be far below replacement.
Ways to lower the Lennox furnace installation bill
Keep the project scope limited to necessary code, venting, safety, and airflow work; avoid paying for duct replacement without evidence it is needed. Choose features based on the home’s requirements, and compare standard and higher-efficiency options using complete installed prices. Scheduling outside the coldest peak-demand periods may improve appointment availability, though savings are not guaranteed.
Get bids that specify the Lennox model, AFUE, labor, removal, permit, thermostat, venting, warranty, and startup tests. Ask whether the contractor can repair compatible existing connections instead of replacing them automatically. The clearest savings usually come from controlling scope and comparing equivalent written quotes.