Why doesn’t my AC cool?

Three people are conversing in a modern kitchen with large windows, wood accents, and a center island. The environment appears relaxed and friendly.

Your air conditioning system isn’t magic. However, as you turn down the temperature, it makes the heat and humidity of summer disappear. Ta-da! So, what do you do if your expected blast of arctic air doesn’t appear on command? As much as your local Carrier HVAC contractor would love to hear from you, taking a few minutes to troubleshoot before you pick up the phone might save you a service call.

Check the thermostat

If the AC system fan is running but not blowing cold air, your thermostat might be set on constant fan instead of cooling. Check to see if it’s on “cool” or “auto” and adjust if needed. If you have a more sophisticated programmable thermostat, be sure it’s not on vacation mode or setback for warmer temperatures.

Check your air filter

A dirty air filter can block airflow and reduce cooling to your home. In more extreme cases it can cause the system to shut down completely. If the airflow is weaker than normal or just not as cool as it should be, locate your system’s air filter, turn the system off, inspect the filter and replace it if it’s dirty.

Check the outdoor unit

If your air conditioner is running but not cooling your home, one issue could be a dirty, clogged or obstructed outdoor unit. Dirt, grass, leaves and other airborne debris can accumulate on the unit’s coil leading to reduced cooling capacity or complete system shut down. Vacuum the coil with a brush attachment or rinse away the debris with a hose. If your system still isn’t cooling, it’s time to call a pro.

Check the indoor unit

Your central air conditioning system includes an indoor coil and air handler unit; typically either a furnace or a fan coil. Visually inspect the indoor unit for:

  • Frost forming on the copper refrigerant tubing coming from the cabinet
  • Excessive condensate drainage near the indoor unit

These are signs that your indoor coil may be frozen or excessively dirty and clogged and it’s time to contact an HVAC professional.

Undersized System

If your AC system keeps you comfortable under normal or moderate conditions but struggles when temperatures become more extreme, it may be undersized for your home. The best way to address sizing issues is to contact us for an accurate assessment of your home’s cooling needs.

Depending on the issue, you may not be able to solve your cooling conundrum yourself. However, understanding what to look for and doing a little troubleshooting on your own can help your us resolve the problem.

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