Santa Rosa reached 109°F during the September 2022 heat wave, an all-time record for the city confirmed by the National Weather Service. When that happens, every HVAC company in the North Bay is booked solid, and homeowners who waited to address warning signs are left sweating through the hottest days of the year. The good news is that most AC systems give clear signals well before they fail, and catching them in May or early June means you still have time to act on your schedule, not the heat’s.
We’ve been serving Santa Rosa and the surrounding North Bay Area since 2010, and the pattern we see every summer is the same: the calls that are hardest to fit in are from homeowners who noticed something off weeks earlier but put it off. These are the signs worth taking seriously before the mercury climbs.
Your AC Is Older Than 10 Years
Central air conditioners typically last 15 to 20 years, but performance degrades meaningfully in the second decade, particularly under the heavy seasonal load that Sonoma County summers place on a system. An older unit running through back-to-back 100-degree days is working harder than it was designed to, and components that were marginal in spring won’t hold up by August.
If your system was manufactured before 2010, there’s an additional financial reality to consider: those units use R-22 refrigerant, which was phased out of U.S. production and import as of January 1, 2020. Recycled R-22 is still available, but as of 2024 it costs between $50 and $175 per pound. A typical recharge requires two to four pounds. A refrigerant leak that would have been a modest repair on a newer system can now run several hundred dollars on a pre-2010 unit, often with no guarantee the leak won’t recur.
A useful rule of thumb for the repair-vs.-replace decision: multiply the system’s age in years by the estimated repair cost. If that number exceeds $5,000, replacement is usually the smarter financial choice. A 14-year-old system facing a $400 repair clears that bar easily. A 12-year-old system facing a $600 compressor repair is much closer to the line.
It’s Short Cycling or Running Constantly
Short cycling is when your AC turns on, runs for a few minutes, shuts off before the thermostat reaches its setpoint, and then kicks on again. It’s one of the more telling symptoms of a system in trouble. The cause can be a low refrigerant charge, a failing compressor, an oversized system, or a thermostat that’s lost its calibration. Whatever the root cause, short cycling puts severe stress on the compressor, which is the single most expensive component in the system to replace.
The opposite problem is just as telling. A system that runs for hours without ever reaching the temperature on the thermostat is losing capacity. This usually points to a refrigerant leak, a dirty evaporator or condenser coil, or a compressor that’s losing compression. Either way, the system is working as hard as it can and failing to deliver. Left untreated through a full Sonoma County summer, both patterns tend to end the same way: a complete breakdown on the worst possible day.
Energy Bills Are Climbing Without Explanation
A meaningful jump in your summer electricity bill, without any change in usage habits or thermostat settings, is one of the earliest measurable signs of a system losing efficiency. It often shows up before any visible or audible symptom, which makes it worth paying attention to even when everything seems to be working fine.
Older systems are rated in SEER, or Seasonal Energy Efficiency Ratio, and efficiency drops as components age. A system operating well below its original SEER rating can use significantly more electricity than a modern unit doing the same work. If your bills have crept up year over year during summer months and you’ve ruled out utility rate increases, the system is working harder than it should to keep up.
Warm Air, Odd Sounds, or Moisture Problems
Warm air coming from the vents while the system is running is one of the more obvious red flags. Before calling for service, confirm the thermostat is set to cool mode and that the temperature setting is below the current indoor temperature. If those check out and the air is still warm, you’re likely looking at a refrigerant leak or a failing compressor.
Unusual sounds from the system are worth noting specifically. Banging or clanking typically means a loose or broken component inside the unit. Squealing or screeching points to a motor bearing or belt issue. Grinding sounds usually indicate a motor that’s failing. None of these get better on their own, and all of them tend to escalate under the sustained load of a summer heat wave.
Moisture issues are trickier to spot but just as important. Water pooling near the indoor air handler usually means the condensate drain is clogged, which is a straightforward fix when caught early. A more serious sign is when your home stays muggy and uncomfortable even though the AC is running: a properly functioning system removes humidity as it cools, and an evaporator coil that’s failing will cool air without drying it, leaving the indoor environment sticky and uncomfortable despite the unit running normally.
Why Timing Matters in Sonoma County
Sonoma County’s inland valleys, including Santa Rosa, are among the areas the county identifies as highest-risk during heat emergencies precisely because temperatures can climb so quickly and so high. The county activates cooling centers when conditions become dangerous, but those resources are for emergencies. A reliable home cooling system is the first line of defense.
What makes Sonoma County summers particularly unforgiving for aging HVAC systems is the combination of prolonged heat events and the surge in service demand they create. When the North Bay hits a multi-day heat event, HVAC companies book up fast. Same-day appointments become difficult to find. Homeowners who acted on warning signs in May get scheduled service. Those who waited get added to a waitlist.
If your system is showing any of these signs, now is the time to have it evaluated. Our team at Indoor Climate Control can assess whether your system needs a tune-up, a repair, or a conversation about replacement before the heat arrives. Reach out to us at (707) 683-8448 and we’ll get you scheduled while the calendar is still open.