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Window air conditioner · Repair Copilot

Window AC not cooling

A plug-in window air conditioner that runs but won't cool almost always has a clogged filter, iced coils, or a dirty condenser — this is the small window unit, NOT central HVAC. Those checks are all DIY. Show SightLine the unit and a friendly handyman persona walks you through getting the cold air back.

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Steps to fix window ac not cooling

  1. Unplug the unit before cleaning anything on it.
  2. Pull and wash the front air FILTER — a filter caked with dust is the #1 reason a window unit stops cooling; let it dry fully before reinserting.
  3. Check the coils: if the front coils are iced up, turn it to fan-only for an hour to melt the ice, then restart on cool.
  4. Clear leaves and dirt from the rear condenser fins and make sure the back of the unit has open airflow outside.
  5. Confirm it's sized for the room and sealed in the window — cold air leaking out around the unit makes it seem like it "won't cool."
  6. If the filter and coils are clean and it still blows warm, the sealed refrigerant system is low or the compressor is failing — that's a repair or a replacement, not DIY.

Safety first: if a step calls for gas, a main water or sewer line, a service panel or main breaker, or a sealed refrigerant system, stop and call a licensed pro — Repair Copilot will tell you when you're there.