Troubleshooting2 min read

What To Do When Your AC Is Not Blowing Cold Air

Frozen coils, dirty filters, and refrigerant issues are common reasons cool air stops reaching your vents. Here is what to check and when to call a pro.

Frost on air conditioner coils — frozen evaporator troubleshooting

When the AC runs but the house does not cool, start with the basics before assuming the worst.

Check the thermostat and mode

Confirm the mode is Cool, the setpoint is below room temperature, and the fan is on Auto unless your installer recommended continuous fan for IAQ equipment.

Inspect the filter

A severely clogged filter chokes airflow across the indoor coil. That can drive coil temperature low enough to freeze condensation into ice. Replace the filter, then leave the fan on with cooling off until the ice melts if you see frost.

Outdoor unit clearance

Weeds, mulch, or furniture pressed against the condenser reduce heat rejection. Clear a few feet around the cabinet and rinse the coil gently if it is packed with debris.

When to call Sub Zero Temp Control

If ice returns after a fresh filter, you hear hissing (possible leak), or the breaker trips, stop cycling the equipment and schedule service. We diagnose refrigerant charge, metering devices, blower performance, and controls so repairs address the root cause.

Need an honest second opinion?

Every option, not just the expensive one.

If you’ve been told your AC or furnace needs replacement and want a thorough, no-pressure diagnosis, give us a call. We serve Vancouver, WA and all of Clark County. We’ll tell you exactly what’s wrong, show you the numbers, and give you every option.

What neighbors say

Neighbors, in their words.

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I highly recommend this honest business! Our hallway control panel went completely dark, and the repairman quickly found a loose wire behind the drywall, restoring our heat in minutes.

WWilliam P.Google · Oct 2026
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My central air completely froze over with ice during a humid weekend, but the tech from Sub Zero came out fast to thaw and fix the refrigerant leak. Everything is running perfectly now, and the house is finally comfortable again!

OOwen P.Google · Oct 2026
★★★★★

Our air stopped working completely and we panicked. The repair guy came over quickly and figured out the wall thermostat just needed new batteries. He swapped them out, checked the rest of the system to be safe, and didn't overcharge us. Very honest and simple service. Highly recommend!

IIan U.Google · Oct 2026

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