A Lennox SL280V furnace typically costs $4,500-$9,000 installed, with a common midrange quote near $6,500 for a straightforward replacement. The final price depends on furnace capacity, local labor, venting and ductwork changes, and whether the quote includes removal, permits, and thermostat upgrades.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| SL280V equipment | $2,500 | $3,400 | $4,500 | Furnace only; size and dealer pricing vary |
| Installed replacement | $4,500 | $6,500 | $9,000 | Typical home, existing gas and duct connections |
| Complex installation | $7,000 | $9,500 | $13,000 | May include duct, vent, electrical, or gas-line work |
| Service call or diagnosis | $90 | $150 | $250 | Separate from installation unless credited |
What homeowners pay for an SL280V replacement
For a standard changeout, the installed price is commonly $4,500-$9,000. The lower end usually reflects a smaller furnace, uncomplicated access, and reuse of compatible connections. Higher quotes can reflect larger capacity, higher local labor rates, new venting, duct modifications, or bundled work such as an air conditioner replacement.
The SL280V is a gas furnace with 80% AFUE efficiency, two-stage heating, and a variable-speed blower. Those features place it above many basic single-stage furnaces, but it is not a high-efficiency condensing model that extracts additional heat through a second heat exchanger. A practical budget for a typical replacement is about $5,500-$7,500 before major duct or vent changes.
Equipment-only pricing often falls around $2,500-$4,500 before tax and installation. Online equipment prices may not reflect a local dealer’s full package, labor, startup, warranty registration, or responsibility for sizing and code compliance. A furnace should be selected by load calculation and compatibility, not simply by matching the old unit’s label.
Assumptions: U.S. residential replacement, standard natural-gas setup, average access, and no major duct reconstruction.
How furnace, labor, and venting appear in the quote
Installation proposals can combine multiple tasks into one total. The table shows typical ranges for common line items; amounts vary by market and may be bundled rather than separately itemized. Ask whether the quote includes startup testing, disposal, permit fees, and any required modifications.
| Quote item | Typical price | What changes the charge | Common billing basis |
|---|---|---|---|
| SL280V furnace | $2,500-$4,500 | Capacity, dealer markup, included controls | Per unit |
| Removal and installation labor | $1,500-$3,200 | Access, crew size, conversion work | Project or hourly |
| Venting and flue adjustments | $200-$1,000 | Flue condition, routing, local code | Per job |
| Thermostat or control work | $150-$700 | Control compatibility and wiring | Per device or job |
| Permit, disposal, and supplies | $150-$650 | Municipality and haul-away needs | Per job |
| Duct transitions or repairs | $250-$1,800 | Plenum fit, leakage, access | Per repair or project |
Labor commonly accounts for roughly $1,500-$3,200 of a standard installation. A useful comparison is the work included rather than the labor line alone: one contractor may include removal and commissioning while another lists them as extras.
Request an itemized quote that identifies the furnace model, installation tasks, excluded work, and permit responsibility. The exact model and capacity matter because a quote for another Lennox series or a different efficiency class is not a direct comparison.
How capacity, venting, and duct changes raise the price
Furnace size is commonly stated in BTU input capacity. Residential models may range roughly from 40,000 to 120,000 BTU, depending on the home and product configuration. Moving from a smaller unit to a larger capacity can add several hundred dollars to equipment pricing, but correct sizing depends on heat loss, climate, insulation, windows, and air leakage.
Two thresholds can make a quote change substantially. First, a home needing a furnace above about 100,000 BTU may require a larger cabinet or different connection work, affecting equipment and installation cost. Second, a flue or vent route that needs more than a short connection adjustment can add $500-$1,500 or more when access is difficult or code requirements call for substantial changes.
Return-air restrictions, undersized ducts, and poor airflow can also affect the variable-speed blower’s performance. Minor transitions or sealing may cost $250-$800; extensive duct repair or replacement can reach $1,500-$5,000 or more, depending on the number of runs and accessibility. A contractor should explain which measured condition supports the proposed duct work.
Home layout and installation access matter as well. A furnace in an open basement is generally faster to replace than one in a tight attic or crawlspace. Moving gas piping, electrical connections, condensate-related components from other equipment, or structural obstructions can add separate charges. Ask for the reason and scope of every capacity-related or duct-related upgrade.
Which installation choices can lower the SL280V bill
Keeping a compatible furnace location, gas connection, electrical circuit, and flue can avoid unnecessary labor. That does not mean an old connection should be reused if it is damaged or fails current requirements; the installer should identify the issue and price the correction separately. A like-for-like replacement often costs less than relocating the unit or changing the heating system type.
Compare at least three written proposals based on the same SL280V capacity and scope. Check whether each includes removal, permit, thermostat, startup, and warranty registration. A quote that is $800 lower may omit a required vent correction or disposal fee, while a higher quote may include duct repairs that are not in the other proposals.
Choose controls that match the furnace’s two-stage operation and blower features without paying for functions the home will not use. A basic compatible thermostat may cost $150-$350 installed; advanced communicating or smart controls can add $300-$900. Confirm compatibility before buying a thermostat separately, since wiring and setup may affect labor.
Control the scope first: avoid optional control upgrades, bundle only work that is genuinely needed, and do not pay for unverified duct replacement. Scheduling during a less busy period can also improve appointment availability, although contractors do not always discount seasonal work.
How long an SL280V installation takes and what labor covers
A straightforward furnace replacement usually takes one workday, often about 6-10 hours for a two-person crew. Complex access, flue changes, duct adjustments, or gas-line corrections can extend work into a second day. Labor pricing is commonly packaged, but local service rates may equate to roughly $75-$150 per technician-hour before overhead and materials.
Typical labor tasks include removing the existing furnace, setting and securing the new cabinet, connecting gas and electrical service, adapting supply and return transitions, and checking combustion and airflow. The final startup should include operation checks for both heating stages and blower settings, along with safety testing appropriate to the installation.
Ask whether the crew will protect floors, haul away the old equipment, and leave the system operating before payment is due. A return visit for a separate thermostat setup or inspection may be charged at $90-$250 if it was not included. Clarify the completion checklist and whether follow-up adjustments are included in the labor price.
Why SL280V quotes differ by U.S. region
Labor and permitting create regional variation even when the furnace model is identical. A standard replacement in a lower-cost Midwest or Southern market may land near $4,500-$7,000, while urban markets in the Northeast, Pacific Coast, or mountain regions may run about 10%-25% higher. These are broad comparisons, not guaranteed local rates.
Rural customers may face a different cost pattern: lower labor rates in some areas but higher travel charges, fewer competing contractors, or longer waits for equipment. Dense cities can have higher wages, parking or access fees, and stricter permit processes. Local gas codes and inspection requirements can add $100-$500 or more to a project.
Climate affects the home’s required capacity and annual heating use, but it does not automatically mean a larger furnace is appropriate. A warm-climate home may need a smaller unit, while a cold-climate property may require more output after a proper heat-loss calculation. Compare quotes from contractors who serve the same local market and include local permit requirements.
SL280V price compared with basic and high-efficiency furnaces
A basic single-stage 80% AFUE furnace may cost about $3,800-$6,500 installed, often $700-$2,000 less than an SL280V package with comparable scope. It can be a lower upfront-cost choice, but it does not provide the same two-stage heat and variable-speed blower configuration. Actual comfort and operating expense depend on installation quality, controls, climate, and fuel prices.
A 90%-plus AFUE condensing furnace often costs approximately $6,500-$12,000 installed. It can reduce gas use compared with an 80% model, but typically needs suitable condensate drainage and venting, which can add installation work. In an existing home, those changes may make the higher-efficiency option more expensive than a simple model comparison suggests.
The SL280V’s 80% AFUE rating means it is not a condensing furnace. Where local rules or utility requirements favor higher efficiency, the available choices may differ. Ask the contractor to compare installed price and expected fuel savings using local rates, rather than presenting an efficiency rating as a guaranteed payback.
Compare complete installed systems, not equipment prices alone, when weighing the SL280V against a single-stage or condensing model. Include required venting, controls, duct corrections, and warranty terms in each alternative.
What warranty, permits, and add-ons do to the total
Warranty coverage depends on product registration, installation terms, and the exact components covered. Confirm the heat exchanger and parts coverage in writing, plus any labor coverage supplied by the dealer. Extended labor protection may add roughly $300-$1,200, depending on term and exclusions; it is separate from the manufacturer’s parts warranty.
Permits and inspections commonly add $100-$500, though fees and requirements vary by municipality. A contractor should state whether the permit is included and who schedules inspection. Code corrections discovered during work may not be part of the original estimate, so ask how additional work is approved and documented before it proceeds.
Common extras include a new thermostat for $150-$900 installed, duct sealing or a transition for $250-$1,800, and a gas-line or electrical correction for about $200-$1,000 when needed. Prices can rise if a concealed problem is discovered. Obtain separate prices for optional accessories and distinguish them from work required for safe operation.
Rebates and tax incentives are not automatic for an 80% AFUE furnace. Utility programs, local rules, and eligibility requirements change, and some incentives target higher-efficiency equipment instead. Check the utility and local program terms before assuming a rebate will reduce the invoice. Use the written proposal to separate required installation work from optional protection, accessories, and incentive assumptions.