Furnace Replacement Cost Calculator

Replacing a furnace alone typically costs about $3,200–$5,000, while a full HVAC replacement (furnace plus AC) runs roughly $7,000–$15,000 or more. The formula the calculator runs is: total = equipment + install labor + ductwork + permit & disposal. Equipment scales with system scope, home size, efficiency tier, and brand; the labor-like costs scale with your region. New ductwork is the single biggest add-on, around $2,000–$5,000. This guide walks the exact math and a full worked example. Every figure is an estimate, not a quote — HVAC bids vary widely by home, which is exactly why the tool shows a range.

Scope Is the Biggest Driver, Not Just the Brand

What you're actually replacing moves the number more than anything else. A gas furnace on its own is the smallest job. Swapping the central AC condenser is similar. A heat pump costs more because one unit does both heating and cooling. And a full furnace-plus-AC replacement is the most expensive, because you're buying and installing two pieces of equipment at once.

The calculator models this as a scope multiplier on a mid-tier, roughly three-ton reference job. An electric furnace lands around two-thirds of the reference; a full furnace-and-AC swap runs nearly double. Pick the scope that matches your project before you compare any quote.

• Furnace only ≈ $3,200–$5,000; full furnace + AC ≈ $7,000–$15,000+
• Heat pumps price differently — one unit heats and cools
• Scope, not brand name, sets the baseline

Equipment vs. Labor: What Your Region Does and Doesn't Move

HVAC equipment is a nationally priced, manufactured good — a furnace or condenser costs about the same in Alabama as in California. So the calculator does NOT scale the equipment by your region. What it does scale is the labor-like side: the install crew's time, ductwork fabrication, permit fees, and old-unit disposal. Those track local wage and permitting costs.

That's why two homes with the identical system can land at different totals: a high-cost-of-living metro pays more for the install and the permit, not for the box itself. Pick your state and the tool applies a regional factor to the labor portion only.

• Equipment = commodity, priced nationally (not region-scaled)
• Install, ductwork, permit, and disposal scale with your region
• Same unit, different metro = different labor, same equipment

Efficiency Tier and Brand Cost More Upfront

Efficiency is measured as AFUE for a furnace and SEER for an AC or heat pump. A high-efficiency unit — think 96% AFUE or 18-plus SEER — costs more upfront than a standard 80% AFUE / 14 SEER model, roughly 25 percent more in equipment in the calculator. You make some of that back in lower energy bills, but the purchase price is higher.

Brand tier stacks on top. Builder-grade equipment runs below the mid-range baseline; premium lines run about 30 percent above it. Both efficiency and brand hit the equipment line, not the labor line, because they're about the box you buy, not the hours to install it.

• High-efficiency (high AFUE/SEER) ≈ +25% equipment, lower bills later
• Builder ≈ 0.85x · mid ≈ 1.0x · premium ≈ 1.3x equipment
• Efficiency and brand move equipment, not labor

Ductwork Is the Wild-Card Add-On

If your existing ducts are sound, you reuse them and ductwork adds nothing. A partial repair adds a flat amount. But full new ductwork is the single largest add-on in a replacement — the calculator prices it at about $1.75 per square foot of home, which lands a typical house in the $2,000–$5,000 range and scales with your region because it's fabricated and installed on site.

Don't assume new ducts unless a contractor says you need them. Leaky or undersized ducts waste the efficiency you just paid for, but reusing good ducts is the easiest way to keep a replacement affordable.

• Reuse good ducts = $0 added; repair = a flat add
• Full new ductwork ≈ $2,000–$5,000 (~$1.75/sq ft, region-scaled)
• Ductwork is labor-heavy, so it scales with local rates

Worked Example: A Full HVAC Swap

Take a 2,000-square-foot home replacing both the furnace and AC with mid-range, standard-efficiency equipment, reusing the existing ducts, with the old units hauled away, at the national-average region.

Equipment is the $2,800 base times the 1.7 full-system scope factor: $4,760. Install labor is the $1,600 base times the 1.65 labor factor: $2,640. Ductwork is $0 because you're reusing. Permit and disposal add $600. That totals $8,000, which the tool brackets as roughly $7,200 to $10,400. Add full new ductwork at $1.75 times 2,000 square feet — $3,500 — and the realistic total jumps to about $11,500.

• Equipment: $2,800 x 1.7 = $4,760
• Install: $1,600 x 1.65 = $2,640
• Permit + disposal: $600 · ducts reused: $0
• Total: $8,000 (range ~$7,200–$10,400); + new ducts ≈ $11,500

Size the System First, Then Price It

Cost and sizing are two different questions. This calculator answers what a replacement costs; it does not tell you what capacity you need. For that, use the BTU Calculator, which estimates the heating or cooling load for your space so you don't oversize. An oversized system short-cycles, controls humidity poorly, and wears out faster — and you'd be paying for capacity you can't use.

The smart order is: size with the BTU Calculator, confirm the tonnage with a contractor's Manual J, then come back here to price the replacement. If you already know your tonnage, switch this tool to 'by system size' and enter it directly.

• BTU Calculator = sizing (what capacity you need)
• This tool = cost (what the replacement costs)
• Never oversize — bigger is not better for HVAC

Why the Total Is a Range

HVAC replacement has one of the widest realistic spreads of any home project, so the calculator brackets the realistic figure with a low end at 0.9x and a high end at 1.3x. The upside is wider because surprises tend to cost more: a tight mechanical closet, a gas line that needs reworking, electrical upgrades for a heat pump, or a permit inspection that flags an extra fix.

Use the realistic figure to budget and the high end to avoid being caught short. Always get two or three on-site quotes — the calculator is for understanding the bid, not replacing it.

• Low = realistic x 0.9 · high = realistic x 1.3
• Upside covers gas/electrical rework, tight access, inspection fixes
• Get two or three on-site quotes before committing

The bottom line

A furnace replacement starts with scope — furnace only, AC only, heat pump, or a full furnace-plus-AC swap — then layers on home size, efficiency tier, brand, and ductwork. Equipment is a nationally priced commodity, so your region scales the install, ductwork, permit, and disposal, never the box. The Furnace Replacement Cost Calculator runs all of it and returns an equipment, labor, ductwork, and permit breakdown with an honest low-to-high range. Size the system first with the BTU Calculator, then price the replacement here — and treat the result as a planning number to read real quotes against, not a guaranteed bid.