🔍 Check these 5 things first
Air filter — when did you last change it?
A clogged filter blocks airflow and causes the system to run without cooling effectively. Pull the filter. If it's dark gray or you can't see through it, it's the culprit.
Fix: Replace with a new filter ($5–$20 at Home Depot). System often starts cooling within 30 minutes.
Thermostat — is it set to COOL or just FAN?
If someone switched the thermostat to FAN only, the blower runs but no cooling happens. Check the mode setting.
Fix: Set mode to COOL, set temperature 3–5° below current room temp, wait 5 minutes.
Circuit breaker — is the AC breaker tripped?
AC units trip breakers, especially at the start of hot weather. Go to your electrical panel and look for the AC breaker (usually a double breaker labeled AC or HVAC).
Fix: Switch it fully off then back to on. If it trips again immediately, call an HVAC tech — that's an electrical issue.
Outdoor unit — is it running? Is it iced over?
Go outside. Is the condenser unit running (fan spinning)? Is there ice visible on the copper pipes or the unit itself?
If iced over: turn AC off, leave fan running, let it defrost 2–3 hours, then replace the filter and restart.
If not running at all: could be a capacitor, contactor, or power issue — now you need a tech.
Vents — are they open and unblocked?
Closed or blocked supply vents cause uneven cooling and can freeze the coil. Check every vent in the home — especially in unused rooms.
Fix: Open all supply vents (at least 80% of them). Blocking vents doesn't save energy — it stresses the system.
Emergency HVAC costs in San Diego (2026)
If you do need to call, know what you're walking into:
- After-hours emergency visit fee: $150–$350 on top of repair cost
- Weekend / holiday rate: +$50–$150 added to labor
- Diagnostic fee (business hours): $75–$125, often applied to repair
- Capacitor replacement (most common emergency fix): $150–$300
- Refrigerant recharge: $200–$450
- Contactor replacement: $150–$350
Frequently asked questions
Why is my AC running but not cooling in San Diego?
Most common causes: dirty air filter blocking airflow, thermostat in fan-only mode, tripped circuit breaker, frozen evaporator coil, or low refrigerant. Check the filter and thermostat first — these solve the problem about 40% of the time without a service call.
What should I check before calling emergency HVAC in San Diego?
Check: (1) air filter — replace if dirty, (2) thermostat — set to COOL not FAN, (3) circuit breaker — reset if tripped, (4) outdoor unit — running and not iced over, (5) vents — open and unblocked. If none fix it, then call.
How much does emergency HVAC service cost in San Diego?
Emergency HVAC service costs $150–$350 for after-hours visit fees, plus repair costs. Many issues that trigger emergency calls can be resolved with a filter change or thermostat reset — worth checking before paying.
What does a frozen AC coil look like?
Ice buildup on the indoor unit's copper pipes or on the unit itself. Common cause: dirty filter or blocked airflow. Fix: turn AC off, let defrost 2–3 hours, replace the filter, then restart.
Checked everything and still stuck?
Text PJ a photo of your indoor unit, thermostat display, and outdoor unit. We'll tell you if it's something you can fix or if it's time to call an HVAC tech — and which questions to ask to avoid the upsell.
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