The 21-year-old prop, who has signed for the club along with Moray Low, is currently in his first season with Championship outfit London Scottish.
"The Championship has a reputation for its physicality and set-piece play," Francis is quoted as saying by the Exeter Express & Echo. "In the Premiership, both those areas are important, but so too are your skills and the pace of the game.
"This season has been tough, but I'm expecting next season to be even tougher. Moving into a Premiership club you know you have to raise your standards, so it's going to be a big challenge for me.
"I know what the coaches are expecting because when I met them they already had my games clipped and went through various points with me. If I'm honest, getting into the Premiership has come a lot quicker than I thought, but it's a great opportunity for me and one that I hope to take with both hands."
Exeter are ninth in the Premiership table.