Germany booked their Brazil berth on Friday with a 3-0 win over a battling Republic of Ireland in Köln with goals by Real Madrid's Sami Khedira, Chelsea's Andre Schürrle and Arsenal's Mesut Özil.
"We're obviously very happy to qualify, but it probably won't sink in until next year," said Germany vice-captain Bastian Schweinsteiger.
Goal-scorer Schürrle admitted it had been a tough night against Noel King's battling Irish.
"We knew the Irish would play defensively, we had to be patient until we eventually found holes in their wall," said the Chelsea winger as Germany enjoyed 75 percent possession.
Second-placed Sweden's 2-1 win at home to Austria leaves Group C winners Germany five points clear ahead of their final qualifier against the Swedes in Stockholm and the Germans want revenge.
When the sides last met in Berlin last October, Germany raced into a 4-0 lead only for Zlatan Ibrahimovic to spark a fight back as the Swedes scored four second-half goals and equalised in the 93rd minute.
"The (German) team has done well and we're happy to qualify, but we definitely have a score to settle against Sweden," said Löw.
"I'll see how the players come out of this match, I might switch things up depending on that, but we want to win in Sweden."
The win over Ireland leaves Germany unbeaten in their last 31 qualification matches for either a World Cup or European Championships dating back to their 3-0 defeat to the Czech Republic in October 2007.
Irish goalkeeper David Forde of Millwall had a busy night as Germany fired in 28 shots compared to the guests' 12.
With both strikers Miroslav Klose and Mario Gomez injured, Löw opted to start Özil up front and the central midfielder struggled on occasion before adding the late third goal.
"We experimented with him a little and he didn't have a lot of opportunities during the game, but took his chance well at the end," said Löw of Özil.
Chelsea winger Schürrle also made his mark with a well-taken goal after central midfielder Toni Kroos had chipped the defence to find Schürrle onside and the Chelsea winger fired past Forde on 58 minutes.
"I had told Andre before the game that I expect a bit more from him -- and he showed me that with his goal," said Löw.