Here is every number you need to make a fast, smart decision, even with sweat running down your back.
What Each Type of System Costs (Installed)
- Central AC unit only: $3,500-$8,000
- Gas furnace only: $2,500-$6,500
- Full system (furnace + AC together): $5,000-$12,000
- Heat pump (heats and cools): $4,500-$10,000
- Ductless mini-split (per zone): $2,000-$5,000
- New ductwork (full replacement): $2,000-$6,000
Replacing the furnace and AC at the same time almost always costs less than doing them separately. The crew is already there, the permits are already pulled, and matched equipment runs more efficiently.
SEER Ratings: The Efficiency Math That Actually Matters
SEER measures cooling efficiency. The legal minimum is now 14 to 15 depending on your region. Here is what stepping up costs and whether it pays back:
- 14-15 SEER (baseline): Cheapest upfront, most expensive to run. Fine for mild climates or if you plan to move within 5 years.
- 16-18 SEER (the sweet spot): About $1,000 to $2,500 more than baseline. In hot climates, the energy savings pay this back in 5 to 8 years.
- 20+ SEER (premium variable-speed): $3,000 to $5,000 premium. Worth it in places like Phoenix or Houston where the AC runs 8 months a year. Also noticeably quieter and better at dehumidifying.
Here is the honest math: in a mild climate, a 20 SEER unit may never pay back its premium before it wears out. Match the efficiency to your climate and how long you plan to stay.
Repair or Replace? Use This Rule
The $5,000 rule: multiply the repair quote by your unit's age in years. If the result is over $5,000, replace it. A $600 repair on a 10-year-old unit equals $6,000, which means replacement wins.
Replace now if any of these are true: the unit is 15 or more years old, it uses R-22 refrigerant (phased out and absurdly expensive to recharge), the compressor is dead ($1,500-$2,500 to fix on borrowed time), or your energy bills jumped 20 percent or more with no other explanation.
Repair it if: the unit is under 10 years old, the fix costs under $500 (capacitor, contactor, thermostat are common), and this is the first real problem it has had.
5 Surprise Costs to Ask About Before You Sign
- Electrical upgrades ($500-$2,000): If your panel cannot handle the new unit's draw, someone has to upgrade it.
- Refrigerant line replacement ($500-$1,500): Old R-22 line sets usually cannot be reused with new equipment.
- Thermostat ($150-$500): Your old thermostat may not communicate with a new variable-speed system.
- Permits ($100-$400): Required almost everywhere. If the quote does not mention permits, ask.
- Ductwork problems: The number one surprise cost in HVAC. Leaky, undersized, or collapsed ducts can add thousands. Get the ducts inspected before you sign, not after.
How to Get a Fair Price (Even in a Heatwave)
- Get 3 or more quotes from licensed HVAC contractors. Same equipment, same house, labor pricing varies wildly.
- Ask for AHRI-matched systems. This is what qualifies you for manufacturer rebates and federal tax credits.
- Check 2026 tax credits: qualifying heat pumps can get you up to $2,000 back under current federal provisions. Your contractor should know the paperwork.
- Schedule in spring or fall if you can wait. Shoulder-season discounts run 5 to 15 percent.
- Walk away from "today only" pricing. Legitimate contractors do not need countdown timers. High-pressure discounts are the clearest red flag in this industry.
Run Your Numbers Now
Our HVAC cost calculator gives you an instant range based on system type, home size, and efficiency tier. Then compare quotes from verified HVAC pros in your area. Going in with a number is the fastest way to kill the sales pressure.