A complete gas HVAC system replacement typically costs $7,000-$15,000, with an average near $10,500 for a standard-size home. The gas HVAC system cost depends most on furnace capacity, air conditioner inclusion, duct condition, equipment efficiency, labor rates, and local code requirements.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Gas furnace replacement | $3,500 | $5,500 | $9,000 | Installed; existing ducts usable |
| Furnace and central AC | $7,000 | $10,500 | $15,000 | Typical 1,500-2,000 sq ft home |
| High-efficiency full system | $11,000 | $15,000 | $22,000 | May include duct or electrical work |
| Furnace equipment only | $1,200 | $2,500 | $5,000 | Before installation and accessories |
What a standard gas furnace and AC replacement costs
A gas furnace alone usually costs $3,500-$9,000 installed. Adding a compatible central air conditioner commonly brings the total to $7,000-$15,000. A larger home, difficult access, premium equipment, or duct repairs can push a complete project above $20,000. These figures assume a licensed contractor, standard equipment, and no extensive redesign.
Equipment is commonly sized around 40,000-100,000 BTU for a home furnace, but square footage alone does not determine capacity; insulation, windows, climate, and layout matter. A central AC system is often priced by ton, with installed equipment and labor commonly landing around $4,000-$8,000 for a 2-3 ton unit. Assumptions: standard access, existing ductwork in serviceable condition, and midrange equipment.
For a typical home replacing both systems, budgeting about $9,000-$13,000 is a practical starting point.
How furnace equipment, labor, and ductwork shape the quote
Quotes bundle equipment and installation differently, so ask contractors to identify what is included. The table shows common portions of a combined furnace-and-AC project; actual shares vary with equipment and site conditions.
| Cost component | Typical range | What changes the charge | Common unit |
|---|---|---|---|
| Furnace and AC equipment | $3,500-$8,000 | Capacity, efficiency, brand tier | $1,200-$5,000 per furnace |
| Installation labor | $2,000-$4,500 | Removal, access, system complexity | $75-$150 per crew-hour |
| Duct repairs or modifications | $500-$3,500 | Leaky runs, poor sizing, added returns | $10-$25 per linear ft |
| Permits and inspection | $100-$600 | City and county requirements | $100-$600 per job |
| Disposal and accessories | $150-$900 | Old equipment, new thermostat, venting | $50-$400 per item |
Labor charges reflect crew time, not necessarily one technician’s hours. Request an itemized quote that separates equipment, labor, ductwork, permits, and disposal.
Which BTU, efficiency, and duct conditions raise the price
Capacity and efficiency are major quote drivers. A furnace rated around 40,000-60,000 BTU may suit some smaller, well-insulated homes, while homes needing 80,000-100,000 BTU equipment generally require a larger unit and may cost more. Proper sizing should use a heating-load calculation rather than a simple square-foot rule.
Standard-efficiency gas furnaces often carry a lower upfront price than units rated 95% AFUE or higher. High-efficiency equipment can add roughly $1,000-$3,000, especially if new PVC venting, condensate drainage, or electrical changes are needed. Duct repairs add cost when leakage exceeds roughly 10%-15%, or when undersized returns restrict airflow. Replacing a furnace without addressing major duct problems may leave comfort issues unresolved.
Why gas HVAC quotes differ across U.S. regions
Installed prices tend to be higher in dense, high-wage metro areas and lower in many rural markets. Compared with a broad national estimate, labor-heavy urban markets such as the Northeast or coastal California may run 10%-25% higher; some lower-cost Midwest and Southern markets may be 5%-15% lower. Local permit fees and contractor availability can shift the total further.
Climate also affects the system selected. Colder regions may need greater heating capacity or more careful duct sealing, while hot, humid areas may place more emphasis on AC capacity and moisture control. Compare local quotes for the same capacity, efficiency rating, included accessories, and warranty.
How long installation takes and what labor covers
A straightforward furnace-only replacement often takes 6-10 hours with a two-person crew. A furnace-and-AC changeout commonly takes 1-2 days, or about 12-20 crew-hours, when existing wiring, lines, and ducts are usable. New ductwork, difficult attic or crawlspace access, or vent changes can extend the job by a day or more.
Labor typically covers disconnecting and removing old equipment, setting and connecting the new system, testing gas and electrical connections, and checking airflow and operation. Ask whether startup testing, thermostat setup, permit handling, and cleanup are included. A quote that omits commissioning or safety checks may not represent the full installation scope.
When venting, duct repairs, or removal add charges
Old equipment removal and disposal may add $100-$400 if not included. A new thermostat may cost $100-$500 installed, while a compatible smart model can cost more. Vent or flue changes can add $300-$1,500, and condensate drainage for a high-efficiency furnace may add $150-$600. These items should be specified rather than hidden in a broad “miscellaneous” fee.
Replacing damaged or poorly sized ductwork can be a substantial extra: partial repairs may run $500-$3,500, while a full duct replacement may reach $3,000-$8,000 or more, depending on home size and access. Have the contractor document why each proposed extra is needed and whether it is required by code or recommended for performance.
Three gas system quotes for different home sizes
A 1,200 sq ft home replacing only a 60,000 BTU furnace might receive a $4,800 quote, including about 8 crew-hours and standard vent connections. A 1,800 sq ft home replacing a furnace and 2.5-ton AC could total $10,200, with roughly 16 crew-hours and no major duct work. A 2,500 sq ft home installing a high-efficiency furnace and 4-ton AC with return-duct improvements could reach $17,500, including about 24 crew-hours.
These examples illustrate quote differences, not fixed national rates. They assume ordinary access and midrange equipment; regional labor, permit fees, and duct conditions can change each amount. Compare the system capacity and work scope before comparing totals.
How to lower the replacement price without cutting safety
Keep the project limited to needed work, but do not skip combustion safety, proper sizing, or required permits. If the AC system is relatively new and compatible, replacing only a failed furnace may avoid buying a complete system; confirm compatibility and warranty terms first. Choose a standard efficiency tier when the payback for a premium model is uncertain.
Get at least three written quotes with matching equipment capacity and efficiency, and compare warranties, labor, removal, permits, and startup testing. Scheduling outside peak heating or cooling emergencies may improve contractor availability, though savings are not guaranteed. Clear scope and comparable bids are usually more useful than choosing the lowest unexplained total.