Key takeaways
- Short answer: Replace your AC if it's over 12–15 years old, uses R-22 refrigerant, needs a compressor, or the repair costs more than half the price of a new unit.
- Under 10 years old + simple part → repair
- Over 12–15 years or R-22 → replace
- Repair cost > 50% of new unit → replace
- Typical hvac cost: $7,000–$12,000 for a combined AC and furnace replacement.
The quick math
Use the $5,000 rule: multiply the unit's age by the repair quote. A 12-year-old AC with a $500 repair scores 6,000 — above 5,000, so replacement usually wins.
| Repair | Typical cost | Usually worth it? |
|---|---|---|
| Capacitor | $100–$400 | Yes, at almost any age |
| Refrigerant leak | $200–$1,500 | Depends on age and leak location |
| Evaporator coil | $400–$2,700 | If under about 8–10 years |
| Compressor | $600–$3,000 | Rarely on systems over 10 years |
When replacement pays off
A new unit can cut cooling costs noticeably if your old system is well below today's SEER2 minimums. The savings are biggest in hot climates where the AC runs for months.
Related questions
Is it worth fixing a 20-year-old AC?
Only for a very cheap repair like a capacitor, and only as a stopgap. At 20 years, plan to replace soon.
How much does a new AC unit cost?
A central AC replacement typically costs $2,500–$9,000 installed, depending on size and efficiency.
Can I just recharge refrigerant instead of fixing a leak?
Recharging without fixing the leak wastes money because the refrigerant leaks out again. A proper repair finds and fixes the leak first.
Other hvac questions homeowners ask
Should I replace my AC and furnace at the same time?
Often yes when both are over 12–15 years old. A matched system runs more efficiently, and you pay for one installation visit and one permit instead of two.
How much does a new AC unit cost for a 2,000 sq ft house?
Most 2,000 sq ft homes need a 3–4 ton system. A central AC replacement alone typically runs $2,500–$9,000 nationally, and replacing both the AC and furnace costs about $7,000–$12,000.
Is it worth repairing a 15-year-old AC?
Usually not. Use the $5,000 rule: multiply the unit's age by the repair cost. If the result is over $5,000, replacing is usually the better value. A $400 repair on a 15-year-old unit scores $6,000.
How long does an HVAC system last?
Furnaces typically last 15–20 years, and central air conditioners and heat pumps 10–15 years. Long cooling seasons and skipped maintenance shorten those lives.
What size AC do I need for my house?
A rough rule is one ton of cooling per 500–600 square feet, but insulation, windows, climate and ductwork change that. Ask for a Manual J load calculation instead of a square-footage guess.
Why is my AC running but not cooling?
The usual causes are a clogged filter, a frozen evaporator coil, a tripped outdoor unit, a failed capacitor or low refrigerant from a leak. Replace the filter and check the breaker first; if that doesn't fix it, call a technician.
How much does an AC tune-up cost?
A tune-up typically costs about $75–$200 per visit. Many companies offer maintenance plans that bundle a spring AC and fall furnace check.
Are there rebates for a new heat pump?
Federal energy tax credits changed in 2025, so check current IRS guidance. Utilities and some states still offer rebates for high-efficiency heat pumps, so ask installers which programs apply.
HVAC at a glance
Timeline
Most AC or furnace swaps take one day. A full system with new ductwork takes 2–5 days.
Permits
Replacing an AC, heat pump or furnace usually needs a mechanical permit, and the installer normally pulls it.
DIY or pro?
Filters, clearing debris from the outdoor unit and flushing the condensate line are safe DIY jobs. Refrigerant, gas and electrical work need a licensed technician.
What HVAC repair and replacement costs
Replacing a central AC and furnace together typically costs $7,000–$12,000 installed. An AC alone runs about $2,500–$9,000 and a furnace $2,000–$6,900, depending on size, efficiency and brand. Most single repairs cost $250–$700.