How Much Does It Cost to Replace a Boiler With a Furnace

Replacing a boiler with a furnace is a major home heating upgrade that affects comfort, efficiency, and expenses. This article explains typical costs, factors that drive price variation, installation steps, efficiency and fuel comparisons, potential incentives, and how to budget for the project so homeowners can make an informed decision.

Item	Typical Range (U.S.)
Furnace Unit (Gas, Mid-Efficiency)	$1,200 – $3,500
Furnace Unit (High-Efficiency Gas)	$2,500 – $6,000
Installation Labor & Materials	$2,000 – $7,000
Boiler Decommissioning & Removal	$300 – $1,200
Ductwork Installation/Retrofit	$1,500 – $10,000+
Complete Conversion Typical Total	$6,000 – $25,000+

Why Homeowners Replace A Boiler With A Furnace

Replacing a boiler with a forced-air furnace occurs for several reasons: homeowners seeking lower operating costs, compatibility with central air conditioning, improved temperature zoning, or to eliminate the safety and maintenance concerns associated with boilers. Modern furnaces often provide faster heating response and easier integration with ducted cooling systems.

Key Cost Components

Furnace Unit Price

Furnace prices vary by fuel type, efficiency rating, capacity, and brand. A basic mid-efficiency gas furnace can cost about $1,200 to $3,500. High-efficiency condensing models with AFUE ratings above 95% commonly range $2,500 to $6,000. Electric furnaces are cheaper to buy but more expensive to operate in many regions.

Installation Labor And Materials

Labor includes mounting the furnace, connecting gas and electrical lines, venting, thermostat setup, and safety checks. Typical labor costs range from $1,200 to $4,000 depending on complexity and local labor rates. Additional materials—venting, flues, gas line upgrades, condensate drains, and wiring—add to the bill.

Ductwork And Distribution System

If the home lacks existing ductwork, installing ducts is often the largest single expense. Basic duct retrofit can run $1,500 to $5,000 in smaller homes. Complex or hard-to-access installations can exceed $10,000. If ductwork exists but needs modification, expect $500 to $3,000 in upgrades.

Boiler Decommissioning And Removal

Removing an old boiler and capping or rerouting piping typically costs $300 to $1,200. Additional plumbing work—converting hydronic piping, removing radiators, or repurposing piping—can increase costs if significant modifications are required.

Permits, Inspections, And Additional Trades

Permits and inspections are required in most jurisdictions and add $100 to $800. If electrical upgrades, structural framing, or drywall repairs are necessary, subcontractors will increase the total project price.

Factors That Drive Cost Variation

Home Size And Heating Load

Heating load determines furnace capacity. Larger homes require higher-capacity units and more extensive ductwork. Accurate load calculations (Manual J) are essential; oversized or undersized furnaces lead to inefficiency and comfort problems.

Fuel Type And Availability

Natural gas furnaces are typically the most cost-effective choice where gas is available. Propane and oil-compatible furnaces are more expensive to operate. Electric furnaces have lower upfront cost but higher operating expense in many U.S. regions.

Conversion Complexity

Converting from a hydronic (boiler-based) system to forced air can require significant plumbing and structural changes. Removing radiators, sloping floors for ducts, or opening ceilings increases labor and repair costs.

Efficiency And Technology Features

High-efficiency condensing furnaces, variable-speed blowers, and two-stage or modulating burners cost more but can yield meaningful energy savings. Smart thermostat integration and zoning systems add to initial costs but improve comfort and efficiency.

Regional Labor Costs And Market Conditions

Labor rates vary widely across the U.S.; metropolitan areas typically see higher installation costs. Material lead times and supply chain issues can also affect pricing and schedule.

Typical Price Scenarios

Basic Replacement With Existing Ductwork

For a medium-sized home with existing ductwork and a straightforward gas hookup, homeowners often pay $4,000 to $8,000 for a mid-efficiency furnace and installation. This scenario assumes minimal duct modifications and no major plumbing work.

High-Efficiency Furnace With Minor Duct Upgrades

A homeowner choosing a high-efficiency 95%+ AFUE furnace with moderate duct improvements and a smart thermostat should expect $7,000 to $12,000. Energy savings and comfort improvements are typical selling points for this upgrade.

Full Conversion From Boiler To Furnace With New Ductwork

Converting a boiler-heated home without ducts commonly ranges from $10,000 to $25,000 or more. This includes furnace unit, full duct system design and installation, boiler removal, permit costs, and finishing work to conceal ducts or access points.

High-End Or Complicated Installations

Large homes with zoned systems, custom ductwork, or additional HVAC features (like ERVs, UV lights, or advanced filtration) can exceed $25,000. Historic homes with limited ceiling access often require creative and costly solutions.

Energy Savings And Operating Cost Comparison

Furnaces and boilers differ in efficiency metrics: AFUE for furnaces and boilers, and system-level efficiencies for hydronic radiant systems. Modern high-efficiency furnaces can exceed 95% AFUE, while efficient condensing boilers are also competitive.

Converting to a furnace may reduce energy use in homes where forced-air systems deliver more uniform and controllable heating, or where a single system can control both heating and cooling. Estimated annual savings depend on fuel costs, local climate, and system efficiencies; homeowners should request a comparative energy analysis from their contractor.

Incentives, Rebates, And Financing

Federal, state, and utility incentives often reduce the net cost of high-efficiency furnaces. Programs may offer rebates for ENERGY STAR units, high AFUE equipment, or integrated heat pump systems. Homeowners can check the Database of State Incentives for Renewables & Efficiency (DSIRE) and local utility websites.

Financing options include HVAC loans, home equity lines, and manufacturer or dealer financing. Some contractors offer deferred interest or low-interest plans to spread upfront costs.

Steps In The Replacement Process

1. Initial Assessment: A contractor performs a home evaluation and Manual J load calculation to size equipment and identify ductwork needs.
2. Estimate And Scope: Detailed written estimate outlining equipment, labor, permits, and timeline.
3. Permits And Scheduling: Contractor obtains permits and schedules work. Expect lead times for high-efficiency units or custom duct materials.
4. Removal And Preparation: Decommissioning the boiler, removing radiators if necessary, and preparing spaces for ducts and furnace placement.
5. Installation: Furnace placement, gas and electrical connections, venting, duct installation or modification, thermostat setup, and commissioning.
6. Inspection And Testing: Final code inspections, combustion safety checks, airflow balancing, and homeowner walkthrough.

Common Pitfalls And How To Avoid Them

Underestimating ductwork complexity is a frequent cost driver. Homeowners should get multiple bids and insist on a Manual J load calculation. Verify that the estimate includes permit fees, testing, and potential contingencies.

Avoid selecting a unit based solely on price; improper sizing leads to short cycling, reduced efficiency, and reduced equipment life. Confirm contractor credentials, ask for references, and check licensing and insurance.

Alternatives To Full Conversion

Hybrid Systems

A hybrid approach pairs a high-efficiency furnace with hydronic heating remaining in place for specific zones, preserving radiator warmth and adding forced-air comfort where needed. This reduces conversion scope and cost.

Mini-Split Heat Pumps

For homes without ducts, ductless mini-splits can provide heating and cooling without major renovations. Initial costs for multiple zones may be comparable to installing ducts but avoid structural disruption.

High-Efficiency Boiler Replacement

If the primary concern is efficiency, replacing the old boiler with a modern condensing boiler may meet goals at lower cost than a full conversion.

How To Budget And Plan

Homeowners should budget for the mid-to-high end of the estimate range to account for unexpected issues. Include a 10–20% contingency for structural or code-related surprises. Request itemized bids, timelines, and warranty details before committing.

Ask contractors about expected annual operating costs and provide fuel bills to help estimate payback on higher-efficiency equipment. Leverage available rebates to reduce net cost and consider financing if needed.

Questions To Ask Potential Contractors

• Will You Perform A Manual J Load Calculation?
• Is The Quote Itemized For Equipment, Labor, Ductwork, Permits, And Contingencies?
• Do You Handle Boiler Decommissioning And Radiator Removal?
• What Warranties Cover The Unit And Labor?
• Can You Provide References And Proof Of Licensing And Insurance?

Resources And Tools

Homeowners can use the ENERGY STAR product finder, DSIRE for incentives, and local utility efficiency programs for rebates. Independent HVAC websites provide guides on Manual J sizing and duct design to help evaluate contractor proposals.

Key Takeaway: Replacing a boiler with a furnace can range from a modest project under $8,000 when ductwork exists to a major conversion exceeding $25,000 for full duct installation and complex demolition. Accurate load calculations, multiple bids, and awareness of incentives help homeowners optimize cost and long-term performance.