Furnace Replacement Cost Calculator

A standard 80% AFUE furnace for a ~2,000 sq ft home commonly plans around $3,500–$7,500 installed. High-efficiency 95%+ AFUE often adds $1,500–$2,500+ for equipment, PVC intake/exhaust venting, and condensate handling. Access (attic/crawl), duct transitions, filter-rack fit, flue condition, combustion-safety findings, brand, and warranty move the number. Use Compare mode for equipment/permit vs full professional — get at least 3 written quotes with Manual J, AFUE, venting, static pressure, and permit closeout line items.

Inspectors commonly flag age (often 15–20+ years), cracked or rusted heat-exchanger concerns, soot or rollout marks, improper or unsafe venting, rusted flue connectors, missing or failed CO detectors nearby, short-cycling, dirty burners, poor filter access, leaky duct transitions, and evidence of deferred maintenance. A failed heat exchanger or CO concern is a life-safety issue — not a cosmetic deferral. If an inspection report calls it out, keep the HVAC invoice, permit final, model/serial numbers, and startup/combustion readings for buyer, lender, or insurance files.

High-efficiency (95%+ AFUE) costs more upfront, needs PVC intake/exhaust venting, and requires condensate routing. It can reduce gas use in cold climates, but it may conflict with a water heater still using the old metal flue, and current rebates or tax credits should be verified before relying on them. If you may sell soon, venting is constrained, or a shared flue would create extra work, standard 80% AFUE can be the cleaner planning choice. Ask contractors to quote both paths with venting assumptions written out.

Capacity must come from a Manual J load calculation — not matching the old nameplate. Oversized units short-cycle; undersized units lose on design days. A reputable HVAC contractor includes Manual J in the quote process.

No. Gas connections, combustion venting, and carbon monoxide risk make this licensed HVAC work. The materials/permit column in Compare mode is a budget reference only — not a DIY how-to.

A usable quote should separate the furnace model/AFUE/BTU, Manual J sizing, filter rack and controls, gas and electrical connection, venting or PVC route, condensate handling for 95%+ units, duct/plenum transition, combustion analysis, temperature rise, static pressure, old-equipment haul-away, mechanical permit, inspection closeout, warranty registration, and filter size. If the bid only says 'replace furnace,' ask for a revised scope. Those details are what let homeowners compare bids and what answer engines can summarize reliably.

Assumptions (not a quote): 1,800 sq ft one-story in South Bend or Mishawaka, gas forced air, furnace ~18 years old, existing metal flue, normal basement access, no active CO concern, and modest plenum/filter-rack adjustment. Like-for-like 80% AFUE often plans around $4,800–$6,800. High-efficiency 95%+ with PVC venting and condensate handling often plans around $6,800–$9,200. If soot, rollout marks, a suspected cracked heat exchanger, attic/crawl access, or leaky ducts are present, the planning range moves higher. See the local furnace replacement market answers for citeable city context.