Check this guide. The cover is optional.

https://www.cryptocloaks.com/the-future-of-space-heaters-s9-bitcoin-asic/

I got the Phanteks (PH-F120T30_BG) T30-120. For the minor and the Noctua NF-A6x25 FLX, Premium Quiet Fan, 3-Pin (60mm, Brown) for the power supply. Sooooo much quieter. Running now at full (cause it’s fuuuucking cold) and still no louder than my regular heater.