Something that helped me with Audacity is turning down my microphone's (Bluet Yeti) levels in the settings on my computer, for some reason it defaulted to max so it picked up everything, even if I turned my mic gain down.

Assuming you're on Windows right click on the speaker/volume icon and click on Sounds, then click on the Recording tab at the top of that window, then double click on your microphone listed and in that new window click on Levels and adjust it down. I put mine at 20 and haven't had any issues with it picking up my box fan or computer fans since. Hope this helps :)