HVAC Diagnostic Tool
Troubleshoot common HVAC problems with our interactive diagnostic tool. Get instant recommendations and determine if you need professional service.
How to Use the Diagnostic Tool
This interactive diagnostic tool walks you through troubleshooting common HVAC problems. Answer questions about what you're experiencing, and get instant recommendations on whether it's a simple fix or requires professional service.
What You'll Be Asked
- What type of system you have (AC, furnace, heat pump, etc.)
- Specific symptoms you're observing
- When the problem occurs
- Any unusual sounds, smells, or behaviors
- Recent changes or maintenance
What You'll Receive
- Likely cause of the problem
- DIY troubleshooting steps you can try safely
- When to call a professional
- Estimated urgency level
- Potential cost range for repairs
Common Bay Area HVAC Problems
These are the most frequent issues we see in Bay Area homes and what they typically mean:
System Won't Turn On
Most common causes: tripped breaker, dead thermostat batteries, switched-off furnace switch, or disconnected safety switch.
Try first: Check your electrical panel, replace thermostat batteries, verify furnace power switch is "ON."
Not Heating or Cooling Enough
Could be clogged air filter, dirty coils, low refrigerant, undersized system, or ductwork issues.
Try first: Replace air filter, check vents are open, ensure outdoor unit has clear airflow.
Strange Noises
Banging, squealing, or grinding sounds often indicate loose parts, worn belts, failing motors, or debris in the system.
Action needed: Turn system off and call for service - continued operation can cause more damage.
Short Cycling (Frequent On/Off)
System turns on and off repeatedly without completing a full cycle. Usually dirty filters, thermostat issues, or oversized equipment.
Try first: Replace filter, adjust thermostat settings. If continues, professional diagnosis needed.
High Energy Bills
Inefficient operation from old equipment, refrigerant leaks, duct leaks, poor insulation, or incorrectly sized system.
Action needed: Schedule energy efficiency assessment to identify specific causes.
Water Leaking
AC condensate drain clogs are common in humid weather. Furnace leaks may indicate cracked heat exchanger (serious).
Action needed: Turn off system and call for service - water damage can escalate quickly.
When to Call a Professional
Some problems are DIY-friendly, but others require professional expertise and tools. Here's how to know the difference:
Call Immediately (Emergency)
- Gas smell or carbon monoxide detector alarm
- Burning smell from furnace or electrical components
- Loud banging or metal-on-metal grinding sounds
- Complete system failure during extreme weather
- Frozen AC coils with system still running
Schedule Service Soon
- System cycles on/off frequently
- Uneven heating or cooling between rooms
- Higher than normal energy bills
- Yellow pilot light flame (should be blue)
- Ice buildup on refrigerant lines
Try DIY First
- System not responding (check breaker/batteries first)
- Weak airflow (check filter and vents)
- Thermostat not reading correctly (replace batteries)
- Outdoor unit not running (check disconnect switch)
Troubleshooting FAQs
How often should I replace my air filter?
In the Bay Area, replace standard 1-inch filters every 1-2 months during heavy use seasons. If you have pets, allergies, or run your system constantly, replace monthly. Thicker 4-5 inch media filters can last 6-12 months.
Is it normal for my heat pump to ice up in winter?
Light frost during defrost cycles is normal, especially in Oakland/Berkeley hills on cold mornings. But thick ice that doesn't melt within 60 minutes indicates a problem—low refrigerant, dirty coils, or faulty defrost controls. Turn off the system and call for service.
Why does my AC blow warm air sometimes?
Common causes: low refrigerant (leak), dirty evaporator coils, failed compressor, or frozen coils from airflow restriction. Start with a clean filter and clear vents. If the problem persists, you likely need refrigerant service or coil cleaning.
Can I fix HVAC problems myself to save money?
Simple maintenance—filters, batteries, clearing debris—is safe and encouraged. But refrigerant work, electrical repairs, gas connections, and internal component replacement require licensing, special tools, and safety equipment. DIY attempts on complex repairs often create bigger, more expensive problems.
What's the typical cost for common HVAC repairs?
In the Bay Area: Thermostat replacement $150-400, capacitor replacement $150-300, refrigerant recharge $300-800, blower motor $400-700, compressor replacement $1,200-2,500. Diagnostic visit typically $100-150 but often waived if you proceed with repairs. Get multiple quotes for major work.
Need Professional Help?
If your diagnostic results indicate a complex issue, our certified HVAC technicians are ready to help with expert repairs and maintenance.