Repair or Replace Your AC: The Numbers That Actually Drive the Decision

The Short Answer

If your repair quote is more than half what a new unit costs, and your AC is over 10 years old, replace it. That’s the core of it. Everything below is the reasoning behind that line.

The 5,000 Rule (and Why It Works)

Multiply the repair cost by the age of the unit in years. If that number exceeds $5,000, replacement is usually the better call financially. So a $400 repair on a 15-year-old system? $6,000. Replace. A $400 repair on a 4-year-old system? $1,600. Fix it.

This isn’t a law of physics, it’s a heuristic, but it holds up well in practice. The logic is simple: older equipment will keep needing repairs. You’re not paying $400 once, you’re paying $400 now and probably $600 next summer and $500 the summer after. At some point you’ve spent replacement money without getting a new unit.

Some HVAC professionals note that the $5,000 threshold has become more conservative given higher equipment costs in recent years. If you’re on the fence, get a full replacement quote before deciding.

Age matters independently too. Most central AC systems are designed for 15 to 20 years. If yours is pushing 12 to 15 and the compressor goes, that’s the heart of the system. Compressor replacements are expensive (often $1,500 to $3,000 or more depending on system size), and you’re putting that money into a unit that’s already most of the way through its life. The math rarely works out in favor of repair at that point.

What Actually Breaks, in Order of Likelihood

Not every breakdown means the same thing. Here’s roughly how repairs stack up by frequency and cost:

Capacitors and contactors. These are the most common failures on AC systems, and they’re relatively cheap to fix, typically in the $250-$500 range for parts and labor depending on your area. A bad capacitor is often what causes your unit to hum but not start, or to start slowly and trip breakers. If your system is otherwise young and healthy, fix it without hesitation.

Refrigerant leaks. R-410A systems that are low on refrigerant almost always have a leak somewhere. Adding refrigerant without finding and fixing the leak just delays the problem. Leak repairs range widely, anywhere from a few hundred dollars to $1,000+ depending on where the leak is. If it’s at an evaporator coil and the coil needs replacing, the job gets expensive fast. On older R-22 systems (pre-2010 equipment), refrigerant itself is now very costly because production and import were banned in 2020. That alone can tip the math toward replacement.

Evaporator or condenser coils. Coil replacement is mid-range to expensive work, often $600 to $2,000+ for evaporator coils and higher for condenser coils. On an older unit, it’s worth getting a full replacement quote before signing off on a coil job.

Compressor failure. As mentioned above, this is the expensive one. On any unit over 10 years old, a compressor failure usually means replacement is the right call unless you have a specific reason to extend that system’s life.

Control boards and electrical components. Variable, but usually mid-range. These are worth fixing on younger systems.

How a Tech Diagnoses the Decision

A good technician doesn’t just fix what’s broken in front of them. They should be looking at the whole picture: the age of the unit, the condition of the coils, refrigerant type, any history of repairs. If you’ve had the same tech out twice in two summers, they should be having this conversation with you proactively.

Ask specifically: “Is this a one-time fix, or is something else likely to follow?” An honest answer to that question is worth more than any rule of thumb.

Also worth asking: what’s the efficiency of your current unit? SEER ratings have increased significantly over the past decade. Newer systems use meaningfully less electricity than older ones. In the Bay Area, where cooling costs aren’t as severe as Phoenix but still add up over summer, that efficiency gap can translate to real savings over the life of the equipment.

Check These First (Before Calling Anyone)

A few things worth ruling out yourself before scheduling a visit:

• Air filter. A clogged filter restricts airflow and can cause the system to freeze up or short-cycle. Replace it. It’s free to fix and not worth a service call to discover.
• Thermostat settings and batteries. Sounds obvious. Still gets missed.
• Breaker. If the outdoor unit isn’t running, check that the disconnect and the breaker are both on.

That’s the list. Everything past that point needs a licensed tech. Refrigerant work requires EPA Section 608 certification. Electrical components inside the unit, especially capacitors, can hold a charge after power is cut. If the filter is clean and the breaker is on and the system still isn’t right, stop there and call.

When to Call Us

If the system isn’t cooling and you’ve already checked the basics, it needs hands-on diagnosis. Same goes for grinding or screeching from the outdoor unit, ice on the refrigerant lines, or the unit tripping breakers repeatedly. None of those are wait-and-see situations.

If you’ve got a repair quote and you’re trying to decide whether it makes sense, that’s worth a second opinion too. A tech who can look at your actual system will give you a more accurate read than any formula.

We serve the East Bay and Tri-Valley. Call (925) 999-4095 or book at bayareahvacservice.com. We’ll get you on the schedule fast, often same or next day when we can. If the repair isn’t worth it, we’ll tell you that up front.

Key takeaways

• Multiply repair cost by unit age in years. If the result exceeds $5,000, replacement usually wins.
• Compressor failure on a unit over 10 years old almost always tips the math toward replacement.
• R-22 refrigerant systems (pre-2010) are expensive to maintain because production and import were banned in 2020, making the refrigerant scarce and costly.
• Check filter, thermostat, and breaker yourself first. Everything else needs a licensed tech.

Related questions

Written by Andrew Kuznetsov. Andrew is the founder and owner of Bay Area HVAC Service (ADRIUM Service Solutions). He holds a California Contractor License (CSLB #1136642), EPA 608 certification, and completed factory training at the Daikin/Goodman plant in Houston in 2025. He writes from direct field experience, not marketing copy.

Further reading

• Mitsubishi Hyper-Heat (H2i): How It Keeps Putting Out Heat When It Gets Cold in the Bay Area , Most people think heat pumps quit when it gets cold. Mitsubishi's Hyper-Heat (H2i) line is built to keep working as temperatures drop, which matters more here than folks expect, especially on cold mornings and up in the East Bay hills.
• Mitsubishi Mini-Split Blinking a Fault Light? What It Means and What to Do , A blinking light on your Mitsubishi indoor head is the system telling you something is wrong. Here is what the blink pattern means, the checks you can safely do yourself, and when to bring in a factory-trained tech.
• Why Your Mitsubishi Mini-Split Is Leaking Water Inside (and How to Fix It) , A Mitsubishi mini-split dripping water inside almost always comes down to condensate that can't drain. Here's what causes it, the safe checks you can do yourself, and when to call a tech.