@Hau 

Hello, how many floors in total? 

Generally speaking, it is suggested to use powerline adapters under the same power circuit due to potential powerline noises; If you have purchased it already, you can give it a go, otherwise, it is not suggested to use them where there is a circuit breaker for each floor. 

Or if you do need boost the wifi signal and the other network expansion devices like range extender cannot satisfy your needs, you can order one powerline adapter first; but before that, please confirm the warranty policy, if it turns out that it does not work well, you can return them within certain time. 

May it help.