Cost to Replace a 4-Ton AC Unit and Furnace: Complete Guide

The cost to replace a 4-ton AC unit and furnace is a common concern for homeowners planning a HVAC upgrade or a full system replacement. This guide breaks down typical price ranges, installation variables, efficiency impacts, and financing options to help make an informed decision. It emphasizes key cost drivers and practical tips to manage expenses while ensuring comfort and code compliance.

Component	Typical Cost Range (Installed)	Notes
4-Ton Air Conditioner (Condenser + Coil)	$3,500 – $7,500	Depends on SEER rating and brand
Furnace (Gas, 80% – 98% AFUE)	$2,500 – $7,000	Higher AFUE raises price
Full System Replacement (Matched)	$6,000 – $14,000+	Includes ductwork, permits, labor
Additional Costs	$300 – $4,000+	Duct repair, electrical, permits, thermostat

How Replacement Costs Are Calculated

HVAC contractors price a 4-ton AC unit and furnace replacement using material, labor, and overhead as base components. Material includes equipment, accessories, and replacement parts such as coils, disconnects, and thermostats. Labor covers removal, installation, testing, and cleanup. Overhead and profit cover contractor operational costs. Local market conditions and demand also affect labor rates and lead times.

Typical Price Ranges For A 4-Ton AC Unit And Furnace

Typical installed prices for a matched 4-ton air conditioner and furnace system vary widely. A basic, entry-level setup might cost around $6,000 to $8,000, while mid-range systems typically sit between $8,000 and $11,000. High-efficiency, variable-capacity systems with advanced features can exceed $12,000 to $16,000 installed. Geography, brand, and installation complexity are major determinants.

Breakdown: 4-Ton AC Unit Costs

A 4-ton outdoor condenser and matched indoor coil typically range from $2,200 for a basic unit to $6,000+ for a high-efficiency model before labor. Higher SEER (Seasonal Energy Efficiency Ratio) ratings command premium prices. Variable-speed compressors and two-stage units increase upfront cost but reduce operating expense. Matching manufacturer components helps warranty coverage and long-term reliability.

Breakdown: Furnace Costs

Furnaces vary by fuel type and efficiency. A basic gas furnace with 80% AFUE often ranges $1,800 to $3,500 installed. Mid-efficiency furnaces (90%+) are commonly $3,000 to $5,500. High-efficiency modulating gas furnaces (95%–98% AFUE) typically cost $4,500 to $7,000 or more. Electric furnaces or heat pumps have different cost structures and incentives.

Labor, Permits, And Additional Fees

Labor for replacing a 4-ton AC unit and furnace can represent 30%–50% of the total installed cost. Typical labor charges vary by region and complexity, often $1,000 to $3,000. Permits, inspections, and disposal fees add $100 to $800. Complex installations requiring structural changes, roof-hoisting, or long duct runs increase labor substantially.

Common Additional Costs To Expect

• Ductwork Repair Or Replacement: $500 to $4,000 depending on scope.
• Electrical Upgrades: $200 to $1,500 if new breakers or wiring are required.
• Gas Line Work: $200 to $1,200 for line replacement or relocations.
• Thermostat Upgrades: $100 to $600 for smart thermostats and controls.
• Refrigerant Retrofits: $200 to $1,200 if older refrigerants require conversion.

How Efficiency And Equipment Choice Affect Long-Term Cost

Higher efficiency equipment reduces energy bills, but the payback period depends on local energy prices and usage. Upgrading from 13 SEER to 16–18 SEER or switching to a high-AFUE furnace lowers operating costs. Variable-speed and two-stage systems provide improved comfort and humidity control, often justifying higher initial investment through energy savings and longer equipment life.

When Ductwork Changes Impact Total Cost

Poor duct design or leakage can negate the benefit of a new 4-ton AC unit and furnace. Sealing and insulating ducts improves system efficiency. Full duct replacement or rerouting can significantly increase costs. Contractors should provide a duct assessment; expect additional quotes for major ductwork remediation.

Permits, Code Compliance, And Warranty Considerations

Local building codes usually require permits for HVAC replacements. Permits ensure installations meet safety and efficiency standards. Proper permit handling protects homeowners and is a condition for many manufacturer warranties. Homeowners should confirm that the contractor will secure permits and provide warranty documentation.

Financing, Rebates, And Tax Incentives

Many homeowners finance HVAC replacements through contractor financing, personal loans, or home improvement loans. Federal and state incentives, utility rebates, and manufacturer promotions can lower net cost. Energy-efficient models often qualify for rebates or federal tax credits; verify eligibility and stackability before purchase to maximize savings.

Choosing The Right Contractor

Choose licensed HVAC professionals with experience installing matched systems. Obtain at least three detailed estimates that include equipment model numbers, SEER/AFUE ratings, warranty coverage, and labor scope. Request references and check online reviews and local licensing boards. A clear written contract reduces the risk of hidden charges.

Installation Best Practices And Quality Checks

Quality installation matters as much as equipment choice. Ensure refrigerant charge is measured and adjusted, airflow is verified, and combustion safety is tested for gas furnaces. Ask the installer to perform a startup checklist and provide a walkthrough of thermostat settings and maintenance tips. Proper commissioning improves performance and longevity.

Energy Savings And Payback Examples

Estimated savings vary with climate and usage. Replacing a 13 SEER AC with a 16 SEER model could yield 15%–23% cooling energy savings. Upgrading a 80% AFUE furnace to a 95% AFUE unit cuts heating fuel use by 15%–25% depending on climate. Calculate payback by dividing net incremental cost by annual energy savings in dollars to estimate years to recoup investment.

Tips To Lower Replacement Cost Without Sacrificing Performance

• Obtain multiple competitive bids and compare full scopes, not just price.
• Consider seasonal promotions in spring or fall when contractors offer discounts.
• Bundle equipment replacement (matched system) to reduce labor duplication.
• Explore utility rebates and federal tax incentives for high-efficiency systems.
• Match equipment sizing to load calculations rather than rule-of-thumb oversizing.

Signs It’s Time To Replace Instead Of Repair

Major indicators favoring replacement include frequent repairs, a system over 12–15 years old, rising energy bills, inconsistent comfort, and use of obsolete refrigerant. If repair costs approach 50% of the value of a new system, replacement typically makes financial sense. A professional load calculation and inspection help decide whether repair or replacement is best.

Checklist For Homeowners Before Scheduling Replacement

1. Request written estimates with equipment model numbers and detailed scope.
2. Confirm contractor licensing, insurance, and references.
3. Ask about permit handling and expected inspection steps.
4. Review warranty terms and what voids them.
5. Plan for timing and any temporary comfort measures during installation.

Frequently Asked Questions

How Long Does Installation Take?

Typical replacement of a 4-ton AC unit and furnace takes one to three days depending on complexity, ductwork, and whether gas or electrical upgrades are needed.

Is It Better To Replace Both Units At The Same Time?

Replacing the AC and furnace as a matched system optimizes efficiency, performance, and warranty coverage and often reduces total labor cost compared to staggered replacements.

Will A Bigger Tonnage Unit Cool Faster?

Oversizing a 4-ton AC unit can lead to short cycling, poor humidity control, and higher operating costs. Properly sized equipment based on a Manual J load calculation is recommended.

How Often Should New Equipment Be Serviced?

Annual preventive maintenance for each system—one visit for the AC and one for the furnace—is advised to maintain efficiency, preserve warranty, and extend equipment life.

Key Takeaways For Budgeting

Budgeting for a 4-ton AC unit and furnace replacement requires accounting for equipment, labor, permits, and potential ductwork or electrical upgrades. Expect a broad installed price range of $6,000 to $14,000+ depending on efficiency, complexity, and region. Prioritize quality installation and proper sizing to protect investment and reduce long-term costs.

For tailored estimates, homeowners should request on-site evaluations from multiple licensed contractors, verify incentives, and review full written proposals before proceeding with replacement.