A room air conditioner that sat unused through winter needs a short check before it carries a Houston summer. Most poor cooling comes from a dirty filter, a clogged coil or a leaky window seal, not a broken unit.
A ten-minute routine
- Filter. Slide it out, wash it in lukewarm water with mild soap and let it dry fully before it goes back in.
- Front and coil. Vacuum the grille and the visible fins with a soft brush. Fins bend easily, so go with the direction of the fins.
- Drain. Check that the drain path at the back is clear of debris and insect nests.
- Window seal. Look for gaps around the unit, torn foam or sagging side panels. Close gaps so hot air does not walk back in.
- Cord and plug. Check for damage and plug directly into a wall outlet.
Run a test
Set the unit to cool and the lowest temperature and let it run 15 minutes. The air from the vent should feel clearly cooler than the room. Listen for rattles. Water dripping outdoors is normal; dripping inside is not.
What cleaning cannot fix
If the fan runs but the air stays warm, a dirty filter does not explain it. Neither does a loud compressor or a unit that cycles on and off every few minutes. Those need a closer look. Right-sizing matters too: a unit too small for the room runs all day without catching up, and a repair will not change that.
Mini-split and ducted systems are not covered by this routine and need a licensed HVAC contractor.
For a unit that still does not cool, see the room air conditioner repair page and check the service area. We book three-hour windows, quote in writing and warrant labor for 30 days.