hot wind; hot air
Refers to a blast or current of hot air, often from a heater, dryer, or natural phenomenon.
I dry my hair with the hot air from the hair dryer.
熱風が吹き付けて、外に出るのがつらかった。
A hot wind was blowing, making it hard to go outside.
熱風 is a hot, scorching wind, the direct opposite of the cool, refreshing 涼風.
hot-blast stove
Compound of 熱 (netsu, 'heat') and 風 (fū, 'wind'), with the reading ねっぷう resulting from a common sound change (netsu + fū → neppū).