Why is my AC freezing up in summer

HVACUpdated March 2026

The answer to 'why is my AC freezing up in summer' is that your air conditioner is likely low on refrigerant or has a blocked airflow. This causes the coils to get too cold, leading to ice buildup that restricts airflow and makes the system freeze up.

Some common causes include a refrigerant leak, a dirty air filter, or a problem with the blower fan. If the coils freeze, it will prevent proper cooling and can eventually damage the compressor. To fix it, you'll need to identify and address the root cause.

Sources

ENERGY STAR— authority

HVAC.com— guide

Step-by-Step Guide

1
Check the air filter
Start by checking the air filter and replacing it if it's dirty. A clogged filter can restrict airflow and cause freezing.
2
Clear any blockages
Make sure there's nothing blocking airflow around the outdoor unit, like leaves or debris. This can also lead to freezing.

Frequently Asked Questions

How do I know if my AC is low on refrigerant?

Signs of a refrigerant leak include poor cooling performance, the outdoor unit running constantly, and ice buildup on the refrigerant lines or coils.

Can I fix a frozen AC unit myself?

Depending on the cause, some minor issues like a dirty air filter can be fixed DIY. But if the problem is a refrigerant leak or a more complex mechanical issue, it's best to call an HVAC professional.

Get help from a local pro

Connect with certified professionals in your area