クーラー

クーラー is from English "cooler" and refers to air conditioning units, specifically for cooling.

COMMON EXPRESSIONS:

• クーラーをつける: to turn on the AC
• クーラーを消(け)す: to turn off the AC
• クーラーが効(き)く: the AC works/is effective
• クーラーが効(き)きすぎる: the AC is too strong

RELATED VOCABULARY:

• エアコン: air conditioner (can heat and cool)
• 冷房(れいぼう): cooling, air conditioning (formal)
• 暖房(だんぼう): heating
• 扇風機(せんぷうき): electric fan

NUANCE:
クーラー emphasizes cooling function, while エアコン (air conditioner) is the more general term for units that can both heat and cool.