Repair or replace your central AC?
Is your AC blowing warm air or making odd sounds? Here is how to decide between a fix and a new unit.
Quick answer
Fix it if it is young. Think new if it is old and needs a big repair.
Central AC tends to last 7 to 15 years[2]. A common repair costs about $400[1]. A new AC averages $5,978[1].
An AC that struggles on a hot day is stressful. But not every problem means a new unit.
Some fixes are cheap. Some signs mean the end is near. This guide helps you tell them apart.
Signs your AC needs help
- Warm air from the vents. It could be a part, low coolant, or a dirty filter.
- Weak airflow. A clogged filter or leaky ducts may be to blame.
- Loud grinding or squealing. A motor or belt may be wearing out.
- Water near the indoor unit. The drain line may be blocked.
- Power bills creep up. An old unit may be working harder to keep up.
Check these first
- Is the thermostat set to cool, and below the room heat?
- Is the filter clean? A dirty one can choke the air flow.
- Is the breaker for the AC on?
- Is the outdoor unit clear of leaves, weeds and junk?
If those all look fine, it is time to call a licensed pro.
How long AC parts last
| Part | Typical life |
|---|---|
| Central air conditioner | 7 to 15 years |
| Outdoor condenser | 8 to 20 years |
| Heat pump | 10 to 15 years |
| Ducts | 60 to 100 years |
Source: InterNACHI[2]. Salt air, heavy use and skipped care can shorten these.
Fix it or replace it?
Fix it when...
- The unit is young.
- One part failed, like a fan motor or valve.
- The ducts just need sealing ($200 to $1,000).
Replace it when...
- It is over 15 years old[3].
- The big part, like the compressor, failed.
- It breaks down every summer.
- Some rooms never get cool.
A common repair costs about $400[1]. The average new AC costs about 15 times that. So one repair on a young unit is often the smart call.
What the new rules mean for you
Since 2023, new AC units must meet a SEER2 score. In the North, the floor is 13[4]. In the Southeast and Southwest it is 14[4] for most home units[4].
You do not have to tear out a working unit. The rule is for new ones. But if you replace it, the new unit must meet the rule where you live.
Ready to price it? Try the AC calculator or read the full central AC cost guide.
Example: a 14-year-old AC
Picture a hot July day and an AC that just quit. The home is made up. The price ranges are real.
The AC is 14 years old. Home inspectors say central units last 7 to 15 years[2]. So this one is near the end. It stops cooling on a hot day.
The pro finds a bad part. A common repair is about $400[1]. A new installed unit is about $5,978[1] on average.
The repair is much cheaper today. But the unit is old, and more parts may fail soon. DOE's guide lists replacing the outside unit as an option once it is past 15 years[3] old[3]. So the owner fixes it now and gets prices for a new unit before next summer.
Checks before you call
Some "broken" ACs just need a small fix. Try these first. They are safe and quick.
- Is the thermostat set to cool, and lower than the room?
- Is the air filter clean? A clogged one can block air.
- Did a breaker trip? Look in your panel.
- Is the outside box covered in leaves or dirt?
Do not open the outside box or touch the wires. Leave that to a pro.
What to ask the HVAC pro
- What part failed, and why?
- Is the system low on coolant? If so, where is the leak?
- What would a repair cost, and what would a new unit cost?
- Is any of this still under warranty?
Florida notes
Florida is in DOE's Southeast region. A new split unit under 45,000 BTU there must reach SEER2 14[4][4]. Before you hire, look up the license on the state DBPR site[5].
Mistakes to avoid
- Buying the same size by habit. Your home may have changed. Ask the pro to check the size.
- Swapping only half the system. A new outside unit with an old coil inside may not match. Ask about both.
- Waiting for a heat wave. Pros are busiest then. Shop in spring or fall if you can.
- Skipping the ducts. Leaky ducts waste cool air. A duct fix runs $200 to $1,000.
A new system tends to come with a parts warranty of 5 to 10 years[1]. Ask what it covers before you sign.
Expert sources we relied on
These are public building codes, laws, license boards, and trade and maker guides. We used them for the rules on this page. None of these groups has looked at or backed Home Repair Report. We just point to what they published.
- Government, law or building code Measure Guideline: Air Conditioner Diagnostics, Maintenance, and Replacement (U.S. Department of Energy, Building America, March 2013; checked ; source [3])
What it supports here: the age at which a new outdoor unit becomes an option - Government, law or building code 2023 Energy Conservation Standards for Residential Central Air Conditioners and Heat Pumps: FAQ (U.S. Department of Energy, Oct 5, 2022 (standards in effect Jan 1, 2023); checked ; source [4])
What it supports here: what the 2023 SEER2 rules cover - Government, law or building code Construction Industry Licensing Board: license types (Florida Department of Business and Professional Regulation, Web page, as checked; checked ; source [5])
What it supports here: how to look up a Florida air conditioning contractor's license
Questions people ask
How long does central AC last?
Home inspectors list 7 to 15 years[2] for central air. The outdoor condenser can last 8 to 20 years[2].
When should I replace an old AC?
A DOE guide lists a new outdoor unit as an option once a system is over 15 years[3] old. Big repairs on an old unit also point toward new.
What does a common AC repair cost?
HomeAdvisor says a common repair, like a blower or valve, costs about $400[1].
Can I keep my old unit if it still works?
Yes. The SEER2 rules apply to new units only. You do not have to replace a working AC.
Is a tune-up worth it?
A basic tune-up costs about $100[1]. A full HVAC check costs $150[1] to $200[1]. It can catch small problems before they grow.
What does a common AC repair cost?
HomeAdvisor puts a common repair, like a blower or valve, at about $400[1].
How we made this page
A computer helper (AI) found the public data. It also wrote the first draft.
Then we checked each number against its source. Each number links to that source.
The AI did not make up any number. We did not make up any person or quote.
We do not show experts or reviewers. We show the math, so you can check it.
Read how we check numbers, our rules for writing and how we fix mistakes. See a mistake? Tell us.
Sources & how we calculated this
How we calculated this
Life spans come from the InterNACHI life chart. The age guide comes from a DOE measure guide for contractors. Repair and replacement prices are HomeAdvisor's published numbers. The cost ratio is our math: the average new AC divided by the common repair price.
The full method is on our methodology page. See a mistake? Read our corrections policy.
Every figure on this page (15), with its source and the date we checked it
| Figure | Value | Source | Checked |
|---|---|---|---|
| Typical life expectancy (InterNACHI): central air conditioner | 7 to 15 years | InterNACHI (International Association of Certified Home Inspectors) | |
| Common AC repair (blower, valve), about | $400 | HomeAdvisor (Angi) | |
| AC unit installed, national average cost | $5,978 | HomeAdvisor (Angi) | |
| Typical life expectancy (InterNACHI): condenser | 8 to 20 years | InterNACHI (International Association of Certified Home Inspectors) | |
| Typical life expectancy (InterNACHI): heat pump | 10 to 15 years | InterNACHI (International Association of Certified Home Inspectors) | |
| Typical life expectancy (InterNACHI): ducting | 60 to 100 years | InterNACHI (International Association of Certified Home Inspectors) | |
| Duct repairs, low | $200 | HomeAdvisor (Angi) | |
| Duct repairs, high | $1,000 | HomeAdvisor (Angi) | |
| Age past which DOE's guide lists replacing the condensing unit as an option | 15 years | U.S. Department of Energy, Building America | |
| Typical manufacturer parts warranty on an AC unit | 5 to 10 years | HomeAdvisor (Angi) | |
| Lowest SEER2 for a new split central AC in the North (from Jan 1, 2023) | 13 | U.S. Department of Energy | |
| Lowest SEER2 for a new split central AC under 45,000 BTU/hr in the Southeast and Southwest | 14 | U.S. Department of Energy | |
| Basic AC tune-up, average | $100 | HomeAdvisor (Angi) | |
| Full HVAC inspection, low | $150 | HomeAdvisor (Angi) | |
| Full HVAC inspection, high | $200 | HomeAdvisor (Angi) |
Sources
- HomeAdvisor (Angi). How Much Does an AC Unit Cost?. Sample/coverage: HomeAdvisor says it surveyed over 10,000 customers about their project costs (site-wide statement on the page).
- InterNACHI (International Association of Certified Home Inspectors). InterNACHI's Standard Estimated Life Expectancy Chart for Homes. Planning estimates under normal conditions, not warranties. InterNACHI notes hot climates sharply shorten asphalt shingle life.
- U.S. Department of Energy, Building America. Measure Guideline: Air Conditioner Diagnostics, Maintenance, and Replacement.
- U.S. Department of Energy. 2023 Energy Conservation Standards for Residential Central Air Conditioners and Heat Pumps: FAQ.
- Florida Department of Business and Professional Regulation. Construction Industry Licensing Board: license types.
