The general consensus these days is actually that if you're using Windows, you should stick with Windows Defender as third party antivirus programs use some weird tricks to hook in to the OS's system calls which actually introduce a bunch of different attack vectors.

This Twitter thread between some AV guy and Google's head of desktop security is pretty enlightening:
https://twitter.com/justinschuh/status/802491391121260544

Essentially the AV industry grew out of Microsoft not taking the whole issue very seriously, which is no longer the case and they respond incredibly quickly to responsible disclosure of vulnerabilities (for context here, Tavis Ormandy is from Google Project Zero and is like the grim reaper of 0-days): https://twitter.com/taviso/status/861751140437839872

tl;dr: be careful - a lot of AV is badly written and can cause more harm than good