Hello   @JorgeCardoso 

The speed will get reduced while signal being transmitted through house powerline, the real wired/ Wi-Fi speed is closely related to the powerline rate and also received speed coming from the router. You could download tpPLC Utliity to check the powerline rate between your powerline kit first, and refer FAQ to to see actual speed is in the resonable range:  Explanation about the Powerline Rate and Actual speed of the Powerline Adapters

Hope this helps.