Straightforward gas-furnace replacement
$3,500–$7,500
A planning range for a same-fuel changeout using the existing distribution system when capacity, venting, gas, electrical and access conditions do not require major correction.
2026 Long Island furnace cost guide
Furnace Replacement Cost on Long Island
A straightforward same-fuel gas-furnace replacement commonly uses a $3,500–$7,500 planning range. The useful comparison begins with scope: capacity, venting, ducts, fuel work and whether the central AC shares components with the furnace.
Planning ranges are not quotes. Home, equipment, fuel, access, code, permit and authorized-scope details control the written project price.
Compare the same project
Four scopes that should not share one price
A useful estimate names the fuel, furnace, distribution system and shared cooling components. Normalize what each contractor includes before comparing totals.
Premium or correction-heavy furnace
$7,500–$10,000+
Variable-speed or modulating equipment, venting changes, return-air corrections, condensate routing, controls and difficult access can move a furnace-only project above the typical range.
Matched furnace plus central AC
$12,000–$22,000
A broader project when the furnace, indoor cooling component and outdoor condenser are replaced as one matched heating-and-cooling system.
Fuel conversion or major distribution work
Design first
Oil-to-gas, furnace-to-heat-pump, chimney or venting changes, new ducts and significant electrical or fuel work require a project-specific design before a responsible price comparison.
Price drivers
What changes a furnace replacement quote
Heating load and capacity
The selected output capacity should follow the home's heating load and duct constraints rather than the old nameplate or a square-foot rule.
Efficiency and venting
AFUE, combustion type, chimney or sidewall venting, combustion air and condensate disposal change both equipment and installation scope.
Blower, ducts and AC match
Blower technology, return-air capacity, filtration, zoning, duct corrections and compatibility with an existing cooling coil affect the proposal.
Fuel, electrical and access
Gas or oil work, wiring, controls, equipment location, removal access, municipal requirements and other-trade coordination can change total cost.
Written estimate checklist
Get these items before comparing totals
DOE and ENERGY STAR guidance both emphasize sizing and installation quality. Ask every bidder to document the same responsibilities.
Exact furnace model, input and output capacity, AFUE and blower type
Heating-load or sizing documentation and the assumptions used
Venting, combustion-air, chimney, condensate and safety-control scope
Gas or oil piping, electrical, thermostat and control responsibility
Return-air, filter, supply-transition, duct and airflow work
Compatibility with the existing or proposed AC coil and outdoor unit
Old-equipment removal, permit and inspection responsibility when applicable
Startup, temperature-rise, combustion and operating checks at completion
Manufacturer registration, parts coverage and separate labor coverage
Exclusions, change-order process, total installed price and payment terms
Choose the right next step
Diagnosis, furnace assessment or matched-system plan?
The failure is not diagnosed
Start with a furnace diagnosis. A known fault, safety finding and repair price create a better comparison than an age-only replacement rule.
Start with furnace diagnosisA furnace-only replacement is planned
Use an installation assessment to verify capacity, venting, ducts, controls, complete scope and a written installed price for the home.
Plan a furnace replacementThe AC is also near replacement
Compare a matched heating-and-cooling proposal with a furnace-only changeout before replacing shared indoor components twice.
Compare full-system scopeRepair vs. replacement
Compare a known repair with a complete replacement proposal. Avoid age-only or fixed-percentage shortcuts.
Use the replacement guidePermits and financing
Keep municipal responsibility, installed price and approved financing terms separate and explicit.
Compare a heat pump
A heat pump provides heating and cooling. Compare the complete design and verify any current utility program separately.
Compare conversion scopeQuestions homeowners ask
Furnace replacement cost FAQ
How much does furnace replacement cost on Long Island in 2026?
Home+ uses $3,500–$7,500 as a planning range for a straightforward same-fuel gas-furnace replacement. Premium or correction-heavy furnace projects commonly plan at $7,500–$10,000+, while a matched furnace plus central AC is a broader $12,000–$22,000 scope. These ranges are not quotes; equipment, load, ducts, venting, fuel work, electrical work, access, permits and the authorized scope determine the written price.
Why do two furnace replacement estimates differ so much?
The proposals may not describe the same job. Compare exact model and capacity, AFUE, blower type, venting, gas or oil work, returns and transitions, controls, permits, removal, startup testing, warranties and exclusions. A furnace-only changeout is also different from a matched furnace-and-AC replacement.
Can a replacement furnace be sized from square footage or the old unit?
Those are useful clues, not a complete sizing method. DOE guidance says heating and cooling loads should be calculated and equipment selected from those loads. The proposal should identify the chosen capacity and the sizing documentation included, especially after insulation, windows or air-sealing changes.
Should I repair or replace my furnace?
If the fault is unknown, begin with a diagnosis. Then compare the known repair, heat-exchanger and venting condition, safety findings, parts availability, comfort or airflow problems, existing coverage and a complete replacement proposal. Age and a fixed repair-percentage rule do not decide every home.
How much does a furnace and central AC cost together?
Home+ uses $12,000–$22,000 as a planning range for a matched furnace-and-central-AC project. The total depends on capacity, equipment match, efficiency, refrigerant components, ducts, venting, electrical work, drainage, controls, access, permits and the written scope.
Is a federal furnace tax credit available for a 2026 replacement?
The current IRS Form 5695 instructions state that the Energy Efficient Home Improvement Credit cannot be claimed for property placed in service after December 31, 2025. A 2026 proposal should not subtract the former federal 25C credit. Any current utility or manufacturer program has separate rules that must be confirmed for the exact project.
Sources: ENERGY STAR quality installation and current IRS Form 5695 instructions.
Turn the planning range into a written project price
Request an in-home replacement assessment for the equipment, capacity, included work, exclusions and total installed price that apply to your home.