The former AS Roma defender made the move last summer.
"I have been happy since I arrived in the league. For me that was very, very important," said the German defender to Deutschen Presse-Agentur.
"It is a completely different football than in Italy. But I think I've done well so far.
"Everyone knows the Premier League, in England it's physically another level. My game is also shaped by the physique, so I met that."
Rudiger also addressed claims that racism inside Italian football drove him to join Chelsea.
"I do not run away from anything. I want to make that clear. I did not run away from racism. I left because I wanted to fulfill the dream of playing in the Premier League.
"Anyone who knows me well knows that I felt 100 percent comfortable in Italy. I respect the country, I respect the people. I also felt very comfortable in Rome."