When summer heat finally hits San Francisco and Marin County, many homeowners flip on their air conditioners only to find… the air isn’t cool. Because AC systems aren’t used year-round in our area, it’s common to discover problems just when you need cooling the most. If your AC is not cooling properly, here’s what might be going on- and what you can do about it.
Common Causes of AC Cooling Problems
1. Dirty or Clogged Air Filters
One of the most overlooked issues is also the easiest to fix. A clogged filter restricts airflow, forcing your AC to work harder and preventing cool air from reaching your rooms.
2. Incorrect Thermostat Settings
Sometimes the problem is simple: the thermostat is set to “fan” instead of “cool,” or the temperature is higher than expected. Double-check your settings before calling for help.
3. Refrigerant Issues
Low refrigerant levels or leaks can significantly reduce your AC’s cooling power. This requires a professional diagnosis and repair.
4. Blocked or Dirty Condenser Unit
Your outdoor unit needs space and airflow. Leaves, dirt, or debris can block the condenser, making it difficult for your AC to release heat.
5. Leaky Ductwork
In older San Francisco and Marin homes, ducts can develop leaks over time, sending cooled air into attics or crawlspaces instead of your living areas.
6. Aging Equipment
If your system is 12-15 years old, reduced performance may be a sign it’s time to consider a replacement or energy-efficient upgrade.
What You Can Check Yourself
Before calling for service, homeowners can safely check:
- Replace or clean the air filter.
- Confirm the thermostat is set correctly.
- Make sure supply and return vents are open and unblocked.
- Inspect the outdoor unit and clear away visible debris.
If you’ve gone through this checklist and the AC still isn’t cooling, it’s time for professional help.
When to Call a Professional
Some problems require more than a DIY fix. Call an HVAC technician if you notice:
- Warm air blowing despite correct thermostat settings.
- Strange noises or ice forming on the unit.
- Persistent weak airflow from vents.
- A sudden spike in energy bills.
Professional technicians can perform diagnostics, test refrigerant levels, inspect ductwork, and make safe repairs to restore comfort quickly.
Quick Diagnostics and Repair in San Francisco & Marin
At Bay Air Heating & Cooling, we know how frustrating it is when your AC won’t keep up on the hottest days. That’s why we provide fast diagnostics and repair services for homeowners across Marin County and San Francisco. Whether it’s a clogged filter, low refrigerant, or a more complex system issue, our licensed team is ready to help you stay cool.