Your AC is getting older, your bills are climbing, and you're not sure if it's time to replace it. Here's how to know — and what to expect when you do.
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There’s a point where patching an old AC stops making sense. Maybe the repair bills are stacking up. Maybe the house never quite gets comfortable during a heat wave, even when the system runs all day. Maybe your PG&E bill has crept up year after year and you’re not sure why.
If any of that sounds familiar, you’re probably already wondering whether it’s time to replace the unit entirely. We’ve helped hundreds of Santa Clara County homeowners make this decision. This guide gives you a straight answer — covering the signs, the process, the costs, and what to watch out for when choosing who does the work.
Most AC systems last between 10 and 15 years. With consistent maintenance, some push to 20. But age alone isn’t the deciding factor — it’s age combined with performance and repair history that tells the real story.
A useful rule of thumb the industry has settled on: multiply the age of your unit by the cost of the repair being quoted. If that number exceeds $5,000, replacement is almost always the smarter financial move. A 12-year-old system facing a $500 repair sits right at the edge. That same system facing a $600 compressor repair is past it.
There’s also the refrigerant question. Older systems running on R-22 — the refrigerant that was phased out of production in the U.S. — are expensive to recharge and impossible to service long-term. If your system still runs on R-22, that alone is a strong signal that replacement isn’t far off.
The most common trigger for a replacement search isn’t a sudden breakdown — it’s a slow decline that’s been easy to ignore. The system runs constantly but the house stays warm. Certain rooms are comfortable while others feel like a different climate entirely. The unit cycles on and off more frequently than it used to, or it makes sounds it never made before.
These aren’t random quirks. They’re symptoms. An AC that short-cycles — turning on and off in rapid intervals — is often oversized for the space, or it’s losing the ability to hold a full cooling cycle as key components wear down. Either way, it’s working harder than it should and delivering less than it used to.
Rising energy bills without a change in usage habits are another clear signal. When a system loses efficiency, it compensates by running longer to achieve the same result. That extra runtime shows up directly on your PG&E statement. In Santa Clara County, where electricity rates are already among the highest in the state, even a modest drop in efficiency translates to real money every month.
The humidity piece matters too, especially in the warmer inland areas of the county — parts of south San Jose, Gilroy, and Morgan Hill where summer temperatures regularly hit the mid-to-high 90s and beyond. A properly functioning AC removes moisture from the air as it cools. When the system starts to fail, humidity lingers. The house feels muggy even when the thermostat reads a reasonable number. That’s not a thermostat problem. That’s a system that’s no longer doing its full job.
If you’ve had two or more repairs in the past 18 months, or if you’re looking at a repair that costs more than a third of what a new system would run, the math usually favors replacement. Not because anyone is trying to sell you something — but because continuing to invest in a declining asset rarely pays off.
Here’s something that doesn’t get talked about enough: the single most common mistake in AC replacement isn’t choosing the wrong brand or skimping on efficiency — it’s installing the wrong size unit.
Bigger is not better when it comes to air conditioning. An oversized unit cools the space so quickly that it shuts off before completing a full cycle. That sounds efficient, but it’s the opposite. The system never runs long enough to pull humidity out of the air, so the house feels clammy. It cycles on and off constantly, which accelerates wear on the compressor. And it uses more energy than a properly sized unit would, because short, frequent cycles are far less efficient than longer, steady ones.
The right way to size a system is through a Manual J load calculation — the ACCA industry standard that accounts for your home’s square footage, ceiling height, insulation levels, window count and orientation, sun exposure, and local climate data. It’s not a guess, and it’s not just dividing square footage by a round number. It’s a real assessment that takes your specific home into account.
When we come out to evaluate a replacement, this is exactly what we do before recommending anything. We look at the home — not just the unit. That step is what separates a system that performs well for 15 years from one that causes problems from the first summer. For homeowners in neighborhoods like Willow Glen or Almaden Valley, where home layouts vary significantly and older construction sometimes has duct configurations that weren’t designed for modern equipment, getting this right from the start matters even more.
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Cost is usually the first question, and it deserves a straight answer. In Santa Clara County, a full a href=”https://www.allfreshtempca.com/services/ac-replacement/”>AC unit replacement typically runs between $3,500 and $12,000 for a home around 2,000 square feet. That’s a wide range, and the spread exists for real reasons — system type, efficiency rating, ductwork condition, and whether any electrical or structural work is needed all affect the final number.
National averages often cited online tend to underrepresent California pricing. Labor costs are higher here, equipment that meets California’s Title 24 efficiency requirements costs more than baseline units sold in other states, and permits — which are required for every significant HVAC installation in the state — add to the total.
Understanding what drives cost helps you evaluate quotes honestly, rather than just picking the lowest number and hoping for the best.
Equipment is the largest single cost, but it’s rarely the whole story. Labor typically accounts for 25 to 35 percent of the total project cost. If your ductwork needs attention — and in roughly 70 percent of replacements, it does — that adds anywhere from $1,000 to $4,000 depending on the scope. Permits and inspections in California generally add $100 to $300, and if your electrical panel needs an upgrade to support a new system, that’s a separate line item.
California also has specific efficiency requirements that affect your equipment options. As of January 1, 2023, new AC installations in California must meet a minimum of 15.2 SEER2 — the updated efficiency standard that replaced the older SEER rating system. Any unit installed below that threshold won’t pass inspection. This isn’t optional, and any contractor suggesting you can skip it to save money is one to avoid.
The good news is that higher-efficiency systems qualify for rebates that can meaningfully offset the upfront cost. PG&E offers rebates based on the efficiency tier of your new system. TECH Clean California has incentives for heat pump installations. And the federal Inflation Reduction Act provides a tax credit of up to 30 percent of equipment cost — up to $600 for a standard AC system and up to $2,000 for a heat pump. These programs are real, they’re available to Santa Clara County homeowners right now, and we help our customers navigate them as part of the replacement process.
One thing worth saying plainly: the cheapest quote is rarely the best deal. A low bid that skips the load calculation, uses a mismatched indoor and outdoor unit, or avoids pulling permits will cost more in the long run — through higher energy bills, voided warranties, and repairs that shouldn’t have been necessary. When you’re comparing proposals, look at what’s included, not just the bottom line.
A lot of homeowners go into this process without knowing what to expect, and that uncertainty makes the whole thing feel bigger than it is. Here’s how it actually works when we do it right.
It starts with an in-home evaluation — not a phone quote, not a guess based on square footage alone. One of our technicians visits your home, assesses the existing system, inspects the ductwork, checks the electrical panel, and performs a load calculation before recommending any equipment. That visit is what makes the recommendation meaningful. Without it, you’re just being sold something.
Once the right system is selected, we handle the permit application with the relevant building department — whether that’s the City of San Jose, the City of Santa Clara, or another municipality in Santa Clara County. You don’t need to deal with that process. We do it, and we schedule the inspection as part of the project.
Installation itself typically takes one day for a standard central AC replacement. If ductwork modifications are needed, or if there’s electrical work involved, it may extend to two days. We test the system thoroughly before we leave — verifying refrigerant charge, airflow, electrical connections, and overall performance — so you’re not discovering a problem after we’re gone.
Because we also handle plumbing, roofing, and electrical work, we’re able to address anything that comes up during the replacement without you needing to coordinate a second contractor. If the condensate line needs rerouting, if a roof penetration needs sealing, or if the panel needs an upgrade to support the new equipment, we handle it. That matters more than it might seem — having one team responsible for the whole scope means nothing falls through the cracks between trades.
After installation, your new system comes with both a manufacturer’s equipment warranty and our workmanship guarantee. If something isn’t right, you call us — not a manufacturer’s hotline.
The equipment matters. The efficiency rating matters. But the contractor you choose matters just as much as any of it — because even a great system installed poorly will underperform, cost more to run, and fail earlier than it should.
Look for a contractor who holds a California C-20 HVAC license, pulls permits as standard practice, and performs a real load calculation before recommending a unit. Ask how long they’ve been working in your area specifically, not just how long the business has existed somewhere.
We’ve been doing this in Santa Clara County since 1985. That’s four decades of working in the same neighborhoods — Willow Glen, Almaden Valley, Campbell, North San Jose — through every climate shift, code update, and technology change the industry has seen. If you’re trying to figure out whether your system is worth saving or whether it’s time to move on, we’re happy to take a look and give you a straight answer. Reach out to All Fresh Temp and we’ll start with a real conversation about your home.
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