How Much Does a New Furnace and AC Cost?

How Much Does a New Furnace and AC Cost?

​If you’re asking “How much does a new furnace and AC cost?”, you’re looking for the total price of replacing both your heating and cooling systems — one of the most common and highest-intent HVAC searches.
👉 A full furnace + AC system replacement typically costs between $8,000 and $20,000 installed in the Thornton, Colorado area, depending on equipment type, efficiency ratings, size, and installation complexity.
Below is a clear, listicle breakdown of costs, what affects pricing, and tips to get the best value for your investment.

Quick Answer: How Much Does a New Furnace and AC Cost?

• Basic furnace + basic AC: $8,000 – $12,000 installed
  
• Mid-range furnace + AC: $12,000 – $16,000 installed
  
• High-efficiency furnace + high-efficiency AC: $16,000 – $20,000+ installed
  

These are typical total ranges for complete HVAC system replacements in Thornton.

1. Why Replace Both Furnace and AC Together?Replacing both systems at the same time can:

• Improve overall efficiency
  
• Reduce long-term repair costs
  
• Ensure matched components
  
• Increase comfort and indoor air quality
  
• Improve home resale value
  

Matched systems (brand + efficiency) perform better and last longer than mismatched or piecemeal replacements.

2. Furnace Costs (Breakdown Included)Gas Furnace$3,000 – $9,000 installed

• Standard efficiency (80-95% AFUE): Lower upfront cost
  
• High-efficiency (95%+ AFUE): Higher install cost, lower heating bills
  

In Colorado’s cold winters, higher AFUE furnaces often deliver the best value over the long term.
Electric Furnace$2,500 – $5,500 installed
Not as common for whole-home heating in Thornton, but an option in specific builds or supplemental zones.

3. Air Conditioner Costs (Breakdown Included)Central AC System$3,500 – $10,500 installed

• Standard SEER (14–15): More affordable
  
• Mid-efficiency (16–18 SEER): Balanced value
  
• High-efficiency (20+ SEER): Best long-term savings
  

Higher SEER units cost more upfront but can lower cooling bills significantly in hot Colorado summers.

4. How System Size Affects CostHVAC systems must be properly sized for your home:
Home SizeFurnace SizeAC SizeTypical Installed Cost~1,000 sq ft60–80 k BTU1.5–2 tons$8,000 – $10,000
1,500 sq ft80–100 k BTU2.5–3 tons$10,000 – $14,000
2,000 sq ft100–120 k BTU3.5–4 tons$12,000 – $18,000
2,500+ sq ft120 k BTU+4+ tons$15,000 – $20,000+A proper Manual J load calculation is essential — oversized or undersized systems waste energy and shorten lifespan.

5. What Installation Costs IncludeA complete furnace + AC replacement typically includes:

• System removal and disposal
  
• New furnace and AC installation
  
• Refrigerant lines and connections
  
• Thermostat installation and calibration
  
• Electrical and gas line work (if needed)
  
• System startup, testing, and safety checks
  
• Permit and inspection fees
  

Labor costs range $2,000 – $5,000+ of the total, depending on complexity.

6. Additional Costs That Affect Total PriceDuctwork Repair or Replacement$500 – $5,000+
Leaky or poorly sized ducts reduce comfort and efficiency.
Electrical or Gas Line Upgrades$200 – $1,500
Older homes often require modern wiring or gas shutoff upgrades.
Smart Thermostat or Zoning$100 – $1,000+
Thermostat upgrades and multi-zone controls improve comfort and can reduce bills.

7. Efficiency Ratings and Long-Term SavingsFurnace Efficiency (AFUE):

• 80–85% = lower cost, higher utility bills
  
• 90–95% = balanced choice
  
• 95%+ = best efficiency and savings
  

AC Efficiency (SEER):

• 14–15 SEER = standard
  
• 16–18 SEER = best value
  
• 20+ SEER = top performance
  

Higher efficiency usually costs more upfront but saves more on utilities — especially in areas with large temperature swings like Thornton.

8. Rebates, Incentives & FinancingColorado utilities and manufacturers often offer:

• Energy efficiency rebates
  
• Federal tax credits
  
• 0% financing plans
  
• Monthly payment options
  

These can significantly lower upfront out-of-pocket costs.
Ask your HVAC Thornton Pros technician about available programs before installation.

9. Replacement vs RepairIf your furnace is over 15 years old or your AC is over 12 years old, replacement may save you money in the long run — even if a repair seems cheaper.
Signs it’s time to replace both systems:

• Frequent breakdowns
  
• Rising energy bills
  
• Uneven comfort
  
• Leaks or corrosion
  
• Old refrigerant (R-22)
  

10. Is a New System Worth It?A new furnace + AC system is worth it if you:

• Want lower energy bills
  
• Need reliable comfort
  
• Plan to stay in your home long-term
  
• Want better air quality and humidity control
  
• Need peace of mind and fewer unexpected repairs
  

Properly installed modern systems often pay back part of their cost in energy savings over their lifespan.

Frequently Asked QuestionsHow much does a new furnace and AC cost installed?A full replacement typically ranges $8,000 – $20,000+ installed, depending on system type, efficiency, size, and installation complexity.
Does replacing both systems at once save money?Yes — it often costs less per system than separate replacements and ensures matched performance and efficiency.
What affects the total cost the most?System size, efficiency ratings (AFUE and SEER), ductwork condition, and labor complexity are the biggest cost drivers.
Should I replace an old HVAC system before it fails?If your system is near the end of its lifespan (furnace ~15 years, AC ~12 years), proactive replacement can save on emergency repair costs.