Today I tested a 20KW combustion heater.
I must admit that the equipment works very well.
The workmanship is satisfactory in relation to the price.

You can buy a similar heater here: https://s.click.aliexpress.com/e/_DBI...

See also:

Chinese webasto 12V:    • Chinese garage webasto 12V 8KW Test U...  
Sunny Gas radiator:    • "Słoneczko" gas heater test Is it wor...