If your window air conditioner has a heat mode but isn’t blowing warm air, try the steps below before requesting service. These steps help reset the unit and make sure it’s set up correctly.

Before You Start

Make sure the unit is securely installed and plugged directly into a working wall outlet (no extension cords or power strips).

Check that the plug and outlet show no signs of damage or burning. If they do, unplug the unit immediately and contact an electrician.

Step-by-Step Troubleshooting

1. Power reset the unit
Unplug the AC from the wall outlet and leave it unplugged for 5 minutes.
This allows the internal controls to reset.

2. Reset the safety plug
After 5 minutes, plug the unit back into the outlet.
On the plug, press both the RESET and TEST buttons (in the order recommended by your product’s label, if shown).
This helps make sure the safety device on the plug is properly engaged.

3. Select Heat mode
On the AC’s control panel or remote:

• Press the Mode button repeatedly
• Stop when the Heat mode indicator lights up
• This confirms that the unit is set to heating, not cooling or fan-only.

4. Set your desired temperature
Press the Up (▲) button to set the temperature higher than the current room temperature.
If the set temperature is too low, the unit may not turn the heater on.

5. Give the unit time to start
After setting the unit to Heat:

• Wait up to 2 minutes for the fan and heating system to start.
  Some models have a built-in delay to protect internal components, so the fan may not start immediately.

6. Check for progress
After a couple of minutes, check:

• Is the fan running?
• Is warm air coming out of the front of the unit?
• Does the display still show Heat mode and your selected temperature?
• If the unit begins to blow warm air, you’re all set. Let it run for a while to warm up the room.
• If there is still no warm air or the unit will not turn on:
• Confirm the outlet has power by testing it with another device (like a lamp).
• Make sure no error codes are showing on the display (if your model has them).
• If everything appears correct and there’s still no heat, the unit may need service.

Important Note for Portable AC Units with Heat

If you’re using a portable AC with a heat function instead of a window unit:

• The exhaust hose must be connected and attached to the window slider kit so the unit can properly expel air while operating.
• If the hose or window kit is not installed correctly, the unit may not heat or cool effectively.