You can fix this
Likely cause: a blocked outdoor unit
The outdoor unit has to shed the heat it pulls from your house. Leaves, grass and shrubs packed around it trap that heat.
Why this happens
Trane lists a dirty condenser coil among the causes of warm air and recommends keeping plants about 2 feet away from the outdoor unit. When the coil fins are blocked, the system can't release heat outside, so it can't cool inside. This Old House says to make sure the unit is completely powered off before you clean around it.
How to fix it
- Set the thermostat to Off, then switch off the disconnect box on the wall next to the outdoor unit.
- Pull leaves, grass clippings and sticks away from the outside of the unit by hand. Don't reach inside the fan grille.
- Trim shrubs and plants back about 2 feet on every side.
- Trane suggests gently hosing the outdoor coil fins from outside. Use a garden hose at low pressure, never a pressure washer.
- Switch the disconnect back on, set the thermostat to Cool, and check the air at a vent after several minutes.
When to stop. If fins are badly bent or crushed, or the unit still won't cool after clearing it, leave the rest to an HVAC technician.
If this does not fix it, tell the HVAC technician
- What was blocking the unit and how long it might have been there.
- Whether cooling improved after clearing it.
- Whether you hosed the coil from outside.
Build the full list: what to tell the HVAC technician.
Start this troubleshooter over
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