Pricing Guide
Furnace Replacement Cost in Denver (2026-2027)
A new gas furnace installed in Denver costs $5,400 to $8,600 for an 80% AFUE single-stage model and $7,500 to $11,200 for a 97% AFUE condensing model, equipment and labor included.
Updated October 13, 2026•By Editorial Staff
Gas furnace installed in Denver: $5,400 to $8,600 for an 80% AFUE single-stage model, $7,500 to $11,200 for a 97% AFUE condensing model. Xcel pays $225 on a qualifying 95%+ AFUE gas furnace through its Whole Home Efficiency program, for installs through 2026.
How much does a new furnace cost in Denver?
A new gas furnace installed in Denver costs $5,400 to $8,600 for an 80% AFUE single-stage model and $7,500 to $11,200 for a 97% AFUE condensing model, equipment and labor included.
Total cost depends on the furnace type (gas vs electric), efficiency rating (80% vs 97% AFUE), BTU capacity for your home's square footage, and installation complexity. High-efficiency models cost more upfront.
For the install itself, brands, and process, see our furnace installation in Denver service page.
Furnace Replacement Cost
Rough estimates for the cost of installing a new furnace:
- 80% AFUE single-stage gas furnace: $5,400 to $8,600 for equipment and installation.
- 97% AFUE condensing gas furnace: $7,500 to $11,200 for equipment and installation, plus $899 to $1,965 for PVC flue if switching from an 80% furnace.
- Electric furnace: $6,100 to $11,200 for the unit and installation, plus $562 to $1,965 for a 220V circuit if converting from gas.
These are estimates and may vary depending on your specific situation. Larger homes or more complex ductwork will increase the installation cost.
Furnace cost by size
- System Size
- 40K BTU Furnace & Installation
- Cost Range
- $5,650 to $8,600
- System Size
- 60K BTU Furnace & Installation
- Cost Range
- $6,100 to $8,950
- System Size
- 80K BTU Furnace & Installation
- Cost Range
- $6,850 to $10,100
- System Size
- 100K BTU Furnace & Installation
- Cost Range
- $7,300 to $10,350
- System Size
- 120K BTU Furnace & Installation
- Cost Range
- $7,700 to $11,200
What's Included in Furnace Installation Cost?
A furnace installation quote from a licensed Denver HVAC contractor typically includes four cost components:
What's in your installation quote
- Equipment (40-60%): The furnace unit. Standard 80% AFUE single-stage gas runs $2,400 to $3,900. 97% AFUE condensing models run $3,550 to $6,100.
- Labor (25-35%): Removal of the old furnace, installation, gas line connections, electrical wiring, and thermostat setup. Typical labor runs $3,000 to $6,900 depending on complexity.
- Materials and supplies (5-15%): PVC venting for high-efficiency units ($899 to $1,965 if upgrading from standard efficiency), gas piping, electrical connections, sheet metal transitions, and mounting hardware.
- Permits and inspection: Denver metro building permits for furnace replacement run $80 to $150. Required for gas line work and new installations.
Not included in most quotes: ductwork modification ($1,600 to $5,550+), electrical panel upgrades ($4,400 to $6,400 if needed for electric furnaces), or thermostat upgrades ($150 to $500). Ask your contractor for a detailed line-item breakdown before signing.
Crawl space and attic furnaces
We no longer take projects where the furnace or air handler sits in an attic or crawl space. A lot of Denver-area homes without basements, ranches especially, have the furnace tucked into one of those spaces, and that placement changes the price with any contractor who still takes the work. Figure on a crawl space adding $400 to $800 and an attic adding $500 to $1,200 on top of the ranges above. Tight clearances slow down every step: demo, venting, gas and condensate runs, and the inspection.
Attics are also a seasonal problem. Front Range attics regularly pass 130 degrees on summer afternoons, hot enough that many companies will not put crews in them during summer at all. That heat risk is a big part of why we stopped doing attic work entirely. If your furnace lives in an attic, line up bids for spring or fall and budget for the access premium.
What size furnace do I need?
Several factors determine the right furnace size for a home:
Furnace sizing factors
- Square footage: Larger spaces need more BTUs. A 1,000 sq ft home needs 40,000 BTUs; a 3,000+ sq ft home needs 120,000 BTUs.
- Climate: Denver's altitude and cold winters (below 0°F nights) mean sizing runs higher than national averages for comparable square footage.
- Insulation: A well-insulated home requires a smaller furnace. Older Denver homes with minimal insulation typically need the higher end of the BTU range.
- Number of windows: Large or older single-pane windows increase heat loss, pushing BTU requirements up.
- Number of floors: Multi-story homes require more BTU capacity to maintain consistent temperature across all levels.
Furnace capacity by home size
| Area Size | Blower Tonnage | Details |
|---|---|---|
| 1000 sq. ft. & below | 2 tons | |
| 1000 sq. ft. to 2000 sq. ft. | 3 to 4 tons | |
| 2000 sq. ft. to 3000 sq. ft. | 4 to 5 tons | |
| 3000 sq. ft. & above | 5 tons |
Why furnace sizing matters
An improperly sized furnace creates problems that compound over time:
Problems caused by wrong furnace size
- Inefficiency: An undersized furnace runs constantly without reaching setpoint, driving up energy bills. An oversized furnace short-cycles, turning on and off every few minutes, which is equally wasteful and hard on components.
- Comfort: Short-cycling leaves cold spots and temperature swings. The furnace never fully distributes heat before shutting off.
- Safety: An oversized furnace can shut off before completing a heating cycle, allowing unburnt fuel to accumulate, increasing carbon monoxide risk.
- Durability: Both undersized and oversized units face accelerated wear. Short-cycling and constant full-load operation shorten the system lifespan and increase repair frequency.
A proper Manual J load calculation accounts for your home's specific characteristics, square footage, insulation, window area, and orientation. Any contractor who quotes a furnace size without performing one is guessing.
Single-Stage vs Two-Stage vs Variable-Speed
Single-stage, two-stage, and variable-speed furnaces differ in how they modulate output, and that difference has real cost and comfort implications:
Single-stage furnace
→Full output or off
Runs at 100% capacity whenever it fires. Lowest upfront cost. Fine for smaller homes or mild climates, but tends to short-cycle in Denver's variable winters.
Two-stage furnace
→Low heat or high heat
Runs at ~65% capacity on mild days, switches to 100% when temperatures drop hard. More efficient than single-stage and quieter during the long low-demand runs.
Variable-speed furnace
→Continuously modulated
Adjusts output in small increments from roughly 40% to 100%. Most efficient type, quietest operation, best humidity control. Also the most expensive.
Two-stage and variable-speed furnaces cost more upfront but can reduce heating bills meaningfully over a 15-20 year lifespan. Your existing ductwork also matters, undersized ducts can negate the efficiency gains of a variable-speed system.
Should I convert my gas furnace to electric?
As solar and electrification become more common, many homeowners ask about converting to electric. A heat pump will better serve most electrification projects. It heats and cools, qualifies for up to $10,000 in rebates, and runs 2-3x more efficiently than an electric furnace. A straight electric furnace makes sense mainly when the home already has solar and cost is the primary concern. Our switchover calculator compares your net cost for each path with current Xcel rebates applied.
A dual-fuel system is the middle path: a heat pump outdoor unit paired with a new gas furnace and coil indoors. Cold-climate heat pumps heat well below zero. Gas takes over below a switchover temperature you and the installer set. The heat pump side of a dual-fuel project qualifies for Xcel's heat pump rebate: $1,500 per heating ton for cold-climate models and $600 per cooling ton for standard models.
Key cost factors for gas-to-electric conversion:
Gas-to-electric conversion considerations
- Electrical panel capacity: Most gas homes have a 100A or 150A panel. An electric furnace typically needs a 200A panel or at minimum a dedicated 240V circuit. Panel upgrades run $4,400 to $6,400.
- New circuit installation: Even with adequate panel capacity, you may need a 220V circuit run to the furnace location, typically $562 to $1,965 depending on distance and access.
- Capping gas lines: Existing gas lines need to be professionally capped or removed. Cost is modest ($56 to $241), but it must be permitted and inspected.
Gas-to-electric conversion costs
- Gas-to-Electric Conversion Costs
- Electrical Panel Upgrade (if required)
- Cost Range
- $4,400 to $6,400
- Gas-to-Electric Conversion Costs
- Adding Electrical Subpanel (if possible)
- Cost Range
- $1,950 to $3,350+
- Gas-to-Electric Conversion Costs
- 220v Circuit Installation
- Cost Range
- $562 to $1,965
- Gas-to-Electric Conversion Costs
- Capping Gas Lines
- Cost Range
- $56 to $241
What is furnace AFUE rating?
The annual fuel utilization efficiency (AFUE) rating measures how much of the fuel a furnace burns actually becomes heat in your home, expressed as a percentage. A 95% AFUE furnace converts 95 cents of every dollar of gas into heat; the remaining 5 cents exits through the flue.
- High-efficiency gas furnaces: 90% AFUE or higher
- Standard-efficiency gas furnaces: 80% to 89% AFUE
As AFUE increases, so does installation cost. Xcel pays $225 on a qualifying 95%+ AFUE gas furnace through its Whole Home Efficiency program, for installs through 2026. The federal 25C tax credit ended December 31, 2025. Rebate programs mostly focus on heat pumps and electrification.
High efficiency vs standard efficiency: which is better?
Key differences between high-efficiency and standard-efficiency gas furnaces:
High-Efficiency (97% AFUE)
Best for most Denver homes
- 97% AFUE: less fuel wasted
- PVC venting runs horizontally through exterior wall, no chimney needed
- Lower monthly gas bills than an 80% furnace
- Fewer greenhouse gas emissions
- Higher upfront cost ($7,500 to $11,200 installed)
- PVC flue adds $899 to $1,965 when upgrading from standard
Standard Efficiency (80% AFUE)
Lower upfront, higher operating cost
- Lower installed cost ($5,400 to $8,600)
- Uses existing metal flue and chimney, a simpler retrofit
- Good option when replacing a standard-efficiency unit like-for-like
- 20% of every gas dollar exits through the flue
- Higher monthly heating bills over 15-20 year lifespan
Colorado's 2026 furnace rule
Since January 1, 2026, a new gas furnace sold in Colorado has to be Ultra-Low NOx or ENERGY STAR. Ultra-Low NOx means 14 nanograms of NOx per joule or less. ENERGY STAR in Colorado means 95% AFUE for furnaces built before July 31, 2026 and 97% for furnaces built on or after that date. The rule comes from HB23-1161 (C.R.S. 25-7-1504).
That leaves two kinds of new furnace: an 80% AFUE furnace that vents up your existing chimney, or a 97% condensing furnace that vents out the wall in PVC. We put in whichever your house allows.
Venting decides the price gap. A 97% condensing furnace needs a PVC run through an exterior wall, which adds $899 to $1,965 if your house doesn't already have one.
The rule only covers new furnaces. The one in your basement now doesn't have to change.
When to Replace Your Furnace
Most gas furnaces last 15-20 years with regular maintenance. In Denver's climate, where furnaces run heavily from October through April, expect the lower end of that range. Signs it's time for a replacement:
Replacement warning signs
- Age over 15 years: Furnaces lose efficiency as components wear. A 20-year-old furnace operating at 70% effective efficiency costs significantly more per heating season than a new 95% AFUE unit.
- Repair costs exceeding $500 per visit: If you're spending $500+ on repairs more than once per season, the total often exceeds the cost difference of a new furnace within 2-3 years.
- Rising energy bills: A sudden 15-25% increase in winter gas bills with no rate change from Xcel Energy usually indicates declining furnace efficiency.
- Uneven heating between rooms: Hot and cold spots often signal a furnace that can no longer maintain consistent output, especially in Denver homes with multiple floors.
- Frequent cycling or unusual noises: Banging, popping, or squealing, or a furnace turning on and off every few minutes, typically indicates worn components.
If your furnace is under 10 years old, repair is usually the better option. Between 10-15 years, compare the repair cost to roughly one-third the price of a new furnace, if the repair exceeds that threshold, replacement makes more financial sense.
If your furnace is old enough that repair no longer adds up, we give free estimates on a replacement.
Ready to install a new furnace?
Free estimate. Most installs are finished in one day.
Looking for furnace installation service in Denver? See our furnace installation page
Investment Options
Three tiers for every budget. All include installation, permits, and warranty.
80% AFUE Single-Stage
Standard efficiency gas furnace.
Single-stage gas furnace
- Lower upfront cost
- Metal flue venting
- Standard installation
- 1 year of labor included
Starting From
$5,400
Full range: $5,400 to $8,600
97% AFUE Condensing
High-efficiency gas furnace.
97% AFUE condensing gas furnace
- Less fuel wasted
- PVC venting (quieter)
- Qualifies for the $225 Xcel furnace rebate
- 1 year of labor included
Starting From
$7,500
Full range: $7,500 to $11,200
Electric Furnace
For electrification projects.
Electric furnace
- No gas required
- Works with solar
- Simpler equipment
- 1 year of labor included
Starting From
$6,100
Full range: $6,100 to $11,200
Prices based on typical home in Denver metro. Actual costs depend on home size, ductwork condition, and equipment selection.
Consider Also
Other systems that may fit your needs and budget.
Heat Pump Installation
Outdoor unit that pairs with a furnace and coil, or an air handler, indoors. Qualifies for Xcel rebates. Price shown is out of pocket after rebates.$14,800 to $18,200Pricing guide · Heat pump
AC Installation
Add cooling to your new furnace installation.$7,700 to $11,200Pricing guide · Cooling
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Frequently Asked Questions
Common questions about furnace installation costs in Denver.