Completely useless. The power of the fan is like a light breeze. You have to sit right next to it to feel the heat. If you put your hand 10 centimeters away, you don't even notice a warm airflow.

Although I bought it for supplementary heating, I found that it heats up the space of a northern room of 25 sq.m. quite well, without insulation and with old aluminum windows that leak. Good construction overall and good quality plastics, which I did not expect for a Chinese device, to be honest. The only downside is that the rotary mechanism stopped working from the first hours of operation due to the grease that was applied during manufacturing. It was fixed by unscrewing the base and applying silicone oil to the moving parts.