Furnace & AC Replacement Cost Calculator
Get an instant free estimate for replacing your furnace and/or air conditioner based on home size, system type, and efficiency.
How is Furnace & AC Replacement Cost Calculated?
HVAC replacement is priced as a complete system. The base cost depends on what you're replacing — from ~$4,500 for a furnace alone to $9,000+ for a full furnace + AC system — then scales with your home's size (tonnage), efficiency tier (SEER2/AFUE), and ductwork condition. A typical 2,000 sq ft home with a standard-efficiency full system runs $8,000-$12,000 installed, with high-efficiency and premium variable-speed systems costing more.
Estimate Your Project Cost
Project Location
Enter your state and zip code for a localized estimate.
Home Size
Enter your home's conditioned (heated & cooled) square footage. This determines the system tonnage needed.
System Type:
Efficiency Tier:
Ductwork Condition:
Additional Options:
Key Factors Influencing HVAC Replacement Rates
System Type & Home Size
What you replace (furnace, AC, both, or a heat pump) sets the base cost, and your home's square footage determines the required tonnage — larger homes need larger, pricier equipment. Replacing both the furnace and AC together costs more upfront than one unit but saves on shared labor and ensures matched, efficient components.
Efficiency & Ductwork
- Standard Efficiency: 14-15 SEER2 / 80% AFUE — the lowest upfront cost. Base rate.
- High Efficiency: 16-18 SEER2 / 90-95% AFUE — about 25% more, lower energy bills.
- Premium Variable-Speed: 19+ SEER2 / 96%+ AFUE — about 55% more, best comfort & efficiency.
- Ductwork: Good existing ducts add nothing; minor mods add ~$800; all-new ductwork adds ~$3,500.
Average HVAC Replacement Cost by System Type
| System Type | Standard Efficiency | High Efficiency | What's Included |
|---|---|---|---|
| Furnace Only | $4,000 - $6,000 | $5,500 - $8,500 | Gas furnace + install |
| Central AC Only | $5,000 - $7,500 | $6,500 - $10,000 | Condenser + coil + lineset |
| Furnace + AC (Full) | $8,000 - $12,000 | $11,000 - $16,000 | Complete matched split system |
| Heat Pump System | $8,000 - $11,000 | $11,000 - $15,000 | Heat + cool, no gas needed |
Common Add-Ons
| Add-On | Cost | Notes |
|---|---|---|
| New Ductwork | ~$3,500 | Replacing aged, leaky, or undersized ducts. |
| Multi-Zone System | ~$2,000 | Dampers & controls for independent room/floor temps. |
| Whole-Home Air Purifier | ~$800 | Media filter or UV/electronic air cleaner. |
| Smart Thermostat | ~$300 | Programmable/learning thermostat with app control. |
| Permit & Inspection | ~$350 | Required in most jurisdictions for HVAC replacement. |
How to Estimate Furnace & AC Replacement Cost Manually
A furnace and AC replacement is priced as a complete system, driven by home size, what's being replaced, efficiency tier, and ductwork condition. Here's how to estimate it yourself.
Step 1: Size the System to Your Home
HVAC equipment is sized by conditioned square footage and climate. A rough rule is one ton of AC per 500-600 sq ft, so a 2,000 sq ft home needs about a 3-3.5 ton system. Bigger homes need bigger equipment and cost more. (A professional load calculation — Manual J — is the accurate method, but square footage is a solid starting estimate.)
Step 2: Choose What to Replace
Decide on the system scope and base cost:
- Furnace Only: $4,000-$7,000 — gas furnace replacement
- Central AC Only: $5,000-$8,000 — condenser + evaporator coil
- Furnace + AC (Full System): $8,000-$13,000 — most common pairing
- Heat Pump System: $8,000-$12,000 — heats and cools, very efficient
Step 3: Pick Efficiency & Check Ductwork
Multiply the base by efficiency tier (standard 1.0×, high-efficiency 1.25×, premium variable-speed 1.55×). Then add ductwork costs: good existing ducts +$0, minor mods +$800, new ductwork +$3,500. Higher SEER2/AFUE costs more upfront but cuts monthly energy bills.
Step 4: Apply the Formula
(System Base × Size × Efficiency) + Ductwork + Add-ons = Total
Example: 2,000 sq ft full system ($9,000 base), standard efficiency, good ducts, plus a smart thermostat ($300): $9,000 × 1.0 × 1.0 + $300 = $9,300.
Frequently Asked Questions
How much does it cost to replace a furnace and AC together in 2026?
In 2026, replacing both a furnace and central AC as a complete system averages $8,000-$14,000 installed, with most homeowners paying around $10,000-$12,000 for a mid-efficiency system in an average-size home. Furnace-only replacement runs $4,000-$7,000, and AC-only runs $5,000-$8,000. Costs scale with home size (larger homes need higher-tonnage equipment), efficiency tier (high-efficiency and variable-speed units cost significantly more), and whether ductwork needs modification or replacement. Replacing both units at once is usually more economical than doing them separately, since you share labor, crane/lift, and permitting costs.
Should I replace my furnace and AC at the same time?
Often yes, especially if both units are aging (10-15+ years). Reasons to replace together: matched components run more efficiently and are designed to work as a system; you save on labor and trip costs by doing one project; modern AC units use refrigerant (R-454B/R-32) that may not pair well with an old coil; and you get a single warranty period. However, if one unit is much newer or still under warranty, replacing only the failed unit may make sense. A key consideration: if you replace just the AC, the new indoor coil must be compatible with your existing furnace's blower for proper airflow and efficiency.
What does SEER2 and AFUE mean?
These are the efficiency ratings for cooling and heating equipment. SEER2 (Seasonal Energy Efficiency Ratio 2) measures air conditioner and heat pump cooling efficiency — higher is better, ranging from about 14 (standard) to 20+ (premium). The 2023 update from SEER to SEER2 uses more realistic testing conditions. AFUE (Annual Fuel Utilization Efficiency) measures gas furnace efficiency as a percentage — an 80% AFUE furnace converts 80% of fuel to heat, while 90-98% AFUE 'condensing' furnaces are far more efficient. Higher ratings cost more upfront but reduce energy bills; the payback depends on your climate, energy prices, and how long you'll stay in the home.
What size HVAC system do I need for my home?
System size (measured in 'tons' for cooling, BTUs for heating) is based on your home's heat load, not just square footage. A common rule of thumb is one ton of cooling per 500-600 sq ft, so a 2,000 sq ft home typically needs 3-3.5 tons. However, proper sizing depends on many factors: climate zone, insulation quality, window area and orientation, ceiling height, and air leakage. Oversized systems short-cycle (turn on and off rapidly), wasting energy and failing to dehumidify; undersized systems run constantly and can't keep up. A professional should perform a Manual J load calculation for an accurate size — square footage alone is just a starting estimate.
Is a heat pump better than a furnace and AC?
It depends on your climate and energy situation. A heat pump both heats and cools using electricity (no gas), and modern cold-climate heat pumps work efficiently even in freezing temperatures. Advantages: very high efficiency (especially vs. electric resistance heat), a single system for year-round comfort, no combustion or carbon monoxide risk, and eligibility for significant federal tax credits and rebates in 2026. A traditional gas furnace + AC may be cheaper to operate where natural gas is inexpensive and winters are severe. Many homes use a 'dual-fuel' setup (heat pump + gas furnace backup) for the best of both. Heat pumps are increasingly favored for their efficiency and electrification incentives.
Are there rebates or tax credits for high-efficiency HVAC?
Yes — in 2026, federal incentives under the Inflation Reduction Act remain significant for qualifying high-efficiency equipment. The Energy Efficient Home Improvement Credit (25C) offers tax credits up to $600 for qualifying AC or furnace units and up to $2,000 for qualifying heat pumps. Income-based rebate programs (HEEHRA) can cover a substantial portion of heat pump costs for eligible households. Many states, utilities, and manufacturers also offer additional rebates. These incentives can offset much of the premium for high-efficiency equipment, improving the payback. Confirm current eligibility, equipment qualification (CEE tiers), and program availability with your installer and a tax professional, since program details change.
How long does HVAC replacement take?
A straightforward furnace and AC replacement using existing ductwork typically takes 1-2 days. A single furnace or AC swap can often be done in a day. Add time if ductwork needs modification or replacement (can extend to 3-5 days), if the system location is difficult to access (attic, tight crawlspace), or if electrical or gas line upgrades are required. The crew removes the old equipment, sets the new furnace and/or condenser and coil, connects refrigerant lines, electrical, and gas, modifies ducts/plenum as needed, and tests and commissions the system. Most homes are without heating/cooling only for the working hours of the changeover.
What are signs I need to replace rather than repair my HVAC?
Consider replacement when: the system is 12-15+ years old (AC) or 15-20+ years (furnace) and nearing end of life; repair costs approach 50% of replacement cost (the '$5,000 rule' — multiply the repair cost by the unit's age; if over $5,000, replace); the AC uses discontinued R-22 refrigerant (expensive and being phased out); energy bills are rising despite normal use; the system needs frequent repairs; rooms are unevenly heated/cooled; or the unit can't keep up on extreme days. A new high-efficiency system can cut energy use 20-40% versus an old one, which helps offset the replacement cost over time.
What's included in an HVAC replacement quote?
A standard furnace/AC replacement quote should include: the equipment (furnace, AC condenser, evaporator coil, or heat pump), removal and disposal of the old equipment, installation labor, a new refrigerant line set or flush (for AC), electrical and gas connections, condensate drainage, a new thermostat (sometimes), permits and inspection, and startup/commissioning. Items sometimes quoted separately: ductwork modification or replacement, electrical panel upgrades, gas line changes, a new concrete pad or rooftop curb, zoning systems, air purification, and extended labor warranties. Always get itemized quotes from at least three licensed HVAC contractors, confirm the equipment brand/model and efficiency ratings, and verify the warranty terms (parts and labor).